diff --git a/exec.c b/exec.c
index 87c7ef3..1118587 100644
--- a/exec.c
+++ b/exec.c
@@ -1681,7 +1681,7 @@ static subpage_t *subpage_init(AddressSpace *as, hwaddr base)
 
     mmio->as = as;
     mmio->base = base;
-    memory_region_init_io(&mmio->iomem, &subpage_ops, mmio,
+    memory_region_init_io(&mmio->iomem, NULL, &subpage_ops, mmio,
                           "subpage", TARGET_PAGE_SIZE);
     mmio->iomem.subpage = true;
 #if defined(DEBUG_SUBPAGE)
@@ -1712,12 +1712,12 @@ MemoryRegion *iotlb_to_region(hwaddr index)
 
 static void io_mem_init(void)
 {
-    memory_region_init_io(&io_mem_rom, &unassigned_mem_ops, NULL, "rom", UINT64_MAX);
-    memory_region_init_io(&io_mem_unassigned, &unassigned_mem_ops, NULL,
+    memory_region_init_io(&io_mem_rom, NULL, &unassigned_mem_ops, NULL, "rom", UINT64_MAX);
+    memory_region_init_io(&io_mem_unassigned, NULL, &unassigned_mem_ops, NULL,
                           "unassigned", UINT64_MAX);
-    memory_region_init_io(&io_mem_notdirty, &notdirty_mem_ops, NULL,
+    memory_region_init_io(&io_mem_notdirty, NULL, &notdirty_mem_ops, NULL,
                           "notdirty", UINT64_MAX);
-    memory_region_init_io(&io_mem_watch, &watch_mem_ops, NULL,
+    memory_region_init_io(&io_mem_watch, NULL, &watch_mem_ops, NULL,
                           "watch", UINT64_MAX);
 }
 
@@ -1800,11 +1800,11 @@ void address_space_destroy_dispatch(AddressSpace *as)
 static void memory_map_init(void)
 {
     system_memory = g_malloc(sizeof(*system_memory));
-    memory_region_init(system_memory, "system", INT64_MAX);
+    memory_region_init(system_memory, NULL, "system", INT64_MAX);
     address_space_init(&address_space_memory, system_memory, "memory");
 
     system_io = g_malloc(sizeof(*system_io));
-    memory_region_init(system_io, "io", 65536);
+    memory_region_init(system_io, NULL, "io", 65536);
     address_space_init(&address_space_io, system_io, "I/O");
 
     memory_listener_register(&core_memory_listener, &address_space_memory);
diff --git a/hw/acpi/core.c b/hw/acpi/core.c
index 42eeace..7206e9c 100644
--- a/hw/acpi/core.c
+++ b/hw/acpi/core.c
@@ -419,7 +419,7 @@ void acpi_pm1_evt_init(ACPIREGS *ar, acpi_update_sci_fn update_sci,
                        MemoryRegion *parent)
 {
     ar->pm1.evt.update_sci = update_sci;
-    memory_region_init_io(&ar->pm1.evt.io, &acpi_pm_evt_ops, ar, "acpi-evt", 4);
+    memory_region_init_io(&ar->pm1.evt.io, NULL, &acpi_pm_evt_ops, ar, "acpi-evt", 4);
     memory_region_add_subregion(parent, 0, &ar->pm1.evt.io);
 }
 
@@ -481,7 +481,7 @@ void acpi_pm_tmr_init(ACPIREGS *ar, acpi_update_sci_fn update_sci,
 {
     ar->tmr.update_sci = update_sci;
     ar->tmr.timer = qemu_new_timer_ns(vm_clock, acpi_pm_tmr_timer, ar);
-    memory_region_init_io(&ar->tmr.io, &acpi_pm_tmr_ops, ar, "acpi-tmr", 4);
+    memory_region_init_io(&ar->tmr.io, NULL, &acpi_pm_tmr_ops, ar, "acpi-tmr", 4);
     memory_region_add_subregion(parent, 8, &ar->tmr.io);
 }
 
@@ -552,7 +552,7 @@ void acpi_pm1_cnt_init(ACPIREGS *ar, MemoryRegion *parent, uint8_t s4_val)
     ar->pm1.cnt.s4_val = s4_val;
     ar->wakeup.notify = acpi_notify_wakeup;
     qemu_register_wakeup_notifier(&ar->wakeup);
-    memory_region_init_io(&ar->pm1.cnt.io, &acpi_pm_cnt_ops, ar, "acpi-cnt", 2);
+    memory_region_init_io(&ar->pm1.cnt.io, NULL, &acpi_pm_cnt_ops, ar, "acpi-cnt", 2);
     memory_region_add_subregion(parent, 4, &ar->pm1.cnt.io);
 }
 
diff --git a/hw/acpi/ich9.c b/hw/acpi/ich9.c
index 4a17f32..8ce52e7 100644
--- a/hw/acpi/ich9.c
+++ b/hw/acpi/ich9.c
@@ -205,7 +205,7 @@ static void pm_powerdown_req(Notifier *n, void *opaque)
 void ich9_pm_init(PCIDevice *lpc_pci, ICH9LPCPMRegs *pm,
                   qemu_irq sci_irq)
 {
-    memory_region_init(&pm->io, "ich9-pm", ICH9_PMIO_SIZE);
+    memory_region_init(&pm->io, NULL, "ich9-pm", ICH9_PMIO_SIZE);
     memory_region_set_enabled(&pm->io, false);
     memory_region_add_subregion(pci_address_space_io(lpc_pci),
                                 0, &pm->io);
@@ -215,11 +215,11 @@ void ich9_pm_init(PCIDevice *lpc_pci, ICH9LPCPMRegs *pm,
     acpi_pm1_cnt_init(&pm->acpi_regs, &pm->io, 2);
 
     acpi_gpe_init(&pm->acpi_regs, ICH9_PMIO_GPE0_LEN);
-    memory_region_init_io(&pm->io_gpe, &ich9_gpe_ops, pm, "apci-gpe0",
+    memory_region_init_io(&pm->io_gpe, NULL, &ich9_gpe_ops, pm, "apci-gpe0",
                           ICH9_PMIO_GPE0_LEN);
     memory_region_add_subregion(&pm->io, ICH9_PMIO_GPE0_STS, &pm->io_gpe);
 
-    memory_region_init_io(&pm->io_smi, &ich9_smi_ops, pm, "apci-smi",
+    memory_region_init_io(&pm->io_smi, NULL, &ich9_smi_ops, pm, "apci-smi",
                           8);
     memory_region_add_subregion(&pm->io, ICH9_PMIO_SMI_EN, &pm->io_smi);
 
diff --git a/hw/acpi/piix4.c b/hw/acpi/piix4.c
index ff559c0..3b95c69 100644
--- a/hw/acpi/piix4.c
+++ b/hw/acpi/piix4.c
@@ -424,7 +424,7 @@ static int piix4_pm_initfn(PCIDevice *dev)
     memory_region_add_subregion(pci_address_space_io(dev),
                                 s->smb_io_base, &s->smb.io);
 
-    memory_region_init(&s->io, "piix4-pm", 64);
+    memory_region_init(&s->io, NULL, "piix4-pm", 64);
     memory_region_set_enabled(&s->io, false);
     memory_region_add_subregion(pci_address_space_io(dev),
                                 0, &s->io);
@@ -671,18 +671,18 @@ static int piix4_device_hotplug(DeviceState *qdev, PCIDevice *dev,
 static void piix4_acpi_system_hot_add_init(MemoryRegion *parent,
                                            PCIBus *bus, PIIX4PMState *s)
 {
-    memory_region_init_io(&s->io_gpe, &piix4_gpe_ops, s, "apci-gpe0",
+    memory_region_init_io(&s->io_gpe, NULL, &piix4_gpe_ops, s, "apci-gpe0",
                           GPE_LEN);
     memory_region_add_subregion(parent, GPE_BASE, &s->io_gpe);
 
-    memory_region_init_io(&s->io_pci, &piix4_pci_ops, s, "apci-pci-hotplug",
+    memory_region_init_io(&s->io_pci, NULL, &piix4_pci_ops, s, "apci-pci-hotplug",
                           PCI_HOTPLUG_SIZE);
     memory_region_add_subregion(parent, PCI_HOTPLUG_ADDR,
                                 &s->io_pci);
     pci_bus_hotplug(bus, piix4_device_hotplug, &s->dev.qdev);
 
     qemu_for_each_cpu(piix4_init_cpu_status, &s->gpe_cpu);
-    memory_region_init_io(&s->io_cpu, &cpu_hotplug_ops, s, "apci-cpu-hotplug",
+    memory_region_init_io(&s->io_cpu, NULL, &cpu_hotplug_ops, s, "apci-cpu-hotplug",
                           PIIX4_PROC_LEN);
     memory_region_add_subregion(parent, PIIX4_PROC_BASE, &s->io_cpu);
     s->cpu_added_notifier.notify = piix4_cpu_added_req;
diff --git a/hw/alpha/typhoon.c b/hw/alpha/typhoon.c
index 1ead187..26628cc 100644
--- a/hw/alpha/typhoon.c
+++ b/hw/alpha/typhoon.c
@@ -735,7 +735,7 @@ PCIBus *typhoon_init(ram_addr_t ram_size, ISABus **isa_bus,
 
     /* Main memory region, 0x00.0000.0000.  Real hardware supports 32GB,
        but the address space hole reserved at this point is 8TB.  */
-    memory_region_init_ram(&s->ram_region, "ram", ram_size);
+    memory_region_init_ram(&s->ram_region, NULL, "ram", ram_size);
     vmstate_register_ram_global(&s->ram_region);
     memory_region_add_subregion(addr_space, 0, &s->ram_region);
 
@@ -744,22 +744,22 @@ PCIBus *typhoon_init(ram_addr_t ram_size, ISABus **isa_bus,
        the flash ROM.  I'm not sure that we need to implement it at all.  */
 
     /* Pchip0 CSRs, 0x801.8000.0000, 256MB.  */
-    memory_region_init_io(&s->pchip.region, &pchip_ops, s, "pchip0", 256*MB);
+    memory_region_init_io(&s->pchip.region, NULL, &pchip_ops, s, "pchip0", 256*MB);
     memory_region_add_subregion(addr_space, 0x80180000000ULL,
                                 &s->pchip.region);
 
     /* Cchip CSRs, 0x801.A000.0000, 256MB.  */
-    memory_region_init_io(&s->cchip.region, &cchip_ops, s, "cchip0", 256*MB);
+    memory_region_init_io(&s->cchip.region, NULL, &cchip_ops, s, "cchip0", 256*MB);
     memory_region_add_subregion(addr_space, 0x801a0000000ULL,
                                 &s->cchip.region);
 
     /* Dchip CSRs, 0x801.B000.0000, 256MB.  */
-    memory_region_init_io(&s->dchip_region, &dchip_ops, s, "dchip0", 256*MB);
+    memory_region_init_io(&s->dchip_region, NULL, &dchip_ops, s, "dchip0", 256*MB);
     memory_region_add_subregion(addr_space, 0x801b0000000ULL,
                                 &s->dchip_region);
 
     /* Pchip0 PCI memory, 0x800.0000.0000, 4GB.  */
-    memory_region_init(&s->pchip.reg_mem, "pci0-mem", 4*GB);
+    memory_region_init(&s->pchip.reg_mem, NULL, "pci0-mem", 4*GB);
     memory_region_add_subregion(addr_space, 0x80000000000ULL,
                                 &s->pchip.reg_mem);
 
@@ -767,7 +767,7 @@ PCIBus *typhoon_init(ram_addr_t ram_size, ISABus **isa_bus,
     /* ??? Ideally we drop the "system" i/o space on the floor and give the
        PCI subsystem the full address space reserved by the chipset.
        We can't do that until the MEM and IO paths in memory.c are unified.  */
-    memory_region_init_io(&s->pchip.reg_io, &alpha_pci_bw_io_ops, NULL,
+    memory_region_init_io(&s->pchip.reg_io, NULL, &alpha_pci_bw_io_ops, NULL,
                           "pci0-io", 32*MB);
     memory_region_add_subregion(addr_space, 0x801fc000000ULL,
                                 &s->pchip.reg_io);
@@ -778,13 +778,13 @@ PCIBus *typhoon_init(ram_addr_t ram_size, ISABus **isa_bus,
     phb->bus = b;
 
     /* Pchip0 PCI special/interrupt acknowledge, 0x801.F800.0000, 64MB.  */
-    memory_region_init_io(&s->pchip.reg_iack, &alpha_pci_iack_ops, b,
+    memory_region_init_io(&s->pchip.reg_iack, NULL, &alpha_pci_iack_ops, b,
                           "pci0-iack", 64*MB);
     memory_region_add_subregion(addr_space, 0x801f8000000ULL,
                                 &s->pchip.reg_iack);
 
     /* Pchip0 PCI configuration, 0x801.FE00.0000, 16MB.  */
-    memory_region_init_io(&s->pchip.reg_conf, &alpha_pci_conf1_ops, b,
+    memory_region_init_io(&s->pchip.reg_conf, NULL, &alpha_pci_conf1_ops, b,
                           "pci0-conf", 16*MB);
     memory_region_add_subregion(addr_space, 0x801fe000000ULL,
                                 &s->pchip.reg_conf);
diff --git a/hw/arm/armv7m.c b/hw/arm/armv7m.c
index 93422bc..4b82bba 100644
--- a/hw/arm/armv7m.c
+++ b/hw/arm/armv7m.c
@@ -124,7 +124,7 @@ static int bitband_init(SysBusDevice *dev)
 {
     BitBandState *s = FROM_SYSBUS(BitBandState, dev);
 
-    memory_region_init_io(&s->iomem, &bitband_ops, &s->base, "bitband",
+    memory_region_init_io(&s->iomem, NULL, &bitband_ops, &s->base, "bitband",
                           0x02000000);
     sysbus_init_mmio(dev, &s->iomem);
     return 0;
@@ -203,11 +203,11 @@ qemu_irq *armv7m_init(MemoryRegion *address_space_mem,
 #endif
 
     /* Flash programming is done via the SCU, so pretend it is ROM.  */
-    memory_region_init_ram(flash, "armv7m.flash", flash_size);
+    memory_region_init_ram(flash, NULL, "armv7m.flash", flash_size);
     vmstate_register_ram_global(flash);
     memory_region_set_readonly(flash, true);
     memory_region_add_subregion(address_space_mem, 0, flash);
-    memory_region_init_ram(sram, "armv7m.sram", sram_size);
+    memory_region_init_ram(sram, NULL, "armv7m.sram", sram_size);
     vmstate_register_ram_global(sram);
     memory_region_add_subregion(address_space_mem, 0x20000000, sram);
     armv7m_bitband_init();
@@ -247,7 +247,7 @@ qemu_irq *armv7m_init(MemoryRegion *address_space_mem,
     /* Hack to map an additional page of ram at the top of the address
        space.  This stops qemu complaining about executing code outside RAM
        when returning from an exception.  */
-    memory_region_init_ram(hack, "armv7m.hack", 0x1000);
+    memory_region_init_ram(hack, NULL, "armv7m.hack", 0x1000);
     vmstate_register_ram_global(hack);
     memory_region_add_subregion(address_space_mem, 0xfffff000, hack);
 
diff --git a/hw/arm/exynos4210.c b/hw/arm/exynos4210.c
index 8186f14..216b9b7 100644
--- a/hw/arm/exynos4210.c
+++ b/hw/arm/exynos4210.c
@@ -241,20 +241,20 @@ Exynos4210State *exynos4210_init(MemoryRegion *system_mem,
     /*** Memory ***/
 
     /* Chip-ID and OMR */
-    memory_region_init_io(&s->chipid_mem, &exynos4210_chipid_and_omr_ops,
+    memory_region_init_io(&s->chipid_mem, NULL, &exynos4210_chipid_and_omr_ops,
         NULL, "exynos4210.chipid", sizeof(chipid_and_omr));
     memory_region_add_subregion(system_mem, EXYNOS4210_CHIPID_ADDR,
                                 &s->chipid_mem);
 
     /* Internal ROM */
-    memory_region_init_ram(&s->irom_mem, "exynos4210.irom",
+    memory_region_init_ram(&s->irom_mem, NULL, "exynos4210.irom",
                            EXYNOS4210_IROM_SIZE);
     vmstate_register_ram_global(&s->irom_mem);
     memory_region_set_readonly(&s->irom_mem, true);
     memory_region_add_subregion(system_mem, EXYNOS4210_IROM_BASE_ADDR,
                                 &s->irom_mem);
     /* mirror of iROM */
-    memory_region_init_alias(&s->irom_alias_mem, "exynos4210.irom_alias",
+    memory_region_init_alias(&s->irom_alias_mem, NULL, "exynos4210.irom_alias",
                              &s->irom_mem,
                              0,
                              EXYNOS4210_IROM_SIZE);
@@ -263,7 +263,7 @@ Exynos4210State *exynos4210_init(MemoryRegion *system_mem,
                                 &s->irom_alias_mem);
 
     /* Internal RAM */
-    memory_region_init_ram(&s->iram_mem, "exynos4210.iram",
+    memory_region_init_ram(&s->iram_mem, NULL, "exynos4210.iram",
                            EXYNOS4210_IRAM_SIZE);
     vmstate_register_ram_global(&s->iram_mem);
     memory_region_add_subregion(system_mem, EXYNOS4210_IRAM_BASE_ADDR,
@@ -272,14 +272,14 @@ Exynos4210State *exynos4210_init(MemoryRegion *system_mem,
     /* DRAM */
     mem_size = ram_size;
     if (mem_size > EXYNOS4210_DRAM_MAX_SIZE) {
-        memory_region_init_ram(&s->dram1_mem, "exynos4210.dram1",
+        memory_region_init_ram(&s->dram1_mem, NULL, "exynos4210.dram1",
                 mem_size - EXYNOS4210_DRAM_MAX_SIZE);
         vmstate_register_ram_global(&s->dram1_mem);
         memory_region_add_subregion(system_mem, EXYNOS4210_DRAM1_BASE_ADDR,
                 &s->dram1_mem);
         mem_size = EXYNOS4210_DRAM_MAX_SIZE;
     }
-    memory_region_init_ram(&s->dram0_mem, "exynos4210.dram0", mem_size);
+    memory_region_init_ram(&s->dram0_mem, NULL, "exynos4210.dram0", mem_size);
     vmstate_register_ram_global(&s->dram0_mem);
     memory_region_add_subregion(system_mem, EXYNOS4210_DRAM0_BASE_ADDR,
             &s->dram0_mem);
diff --git a/hw/arm/highbank.c b/hw/arm/highbank.c
index 4405dbd..c02afce 100644
--- a/hw/arm/highbank.c
+++ b/hw/arm/highbank.c
@@ -149,7 +149,7 @@ static int highbank_regs_init(SysBusDevice *dev)
     HighbankRegsState *s = FROM_SYSBUS(HighbankRegsState, dev);
 
     s->iomem = g_new(MemoryRegion, 1);
-    memory_region_init_io(s->iomem, &hb_mem_ops, s->regs, "highbank_regs",
+    memory_region_init_io(s->iomem, NULL, &hb_mem_ops, s->regs, "highbank_regs",
                           0x1000);
     sysbus_init_mmio(dev, s->iomem);
 
@@ -227,12 +227,12 @@ static void highbank_init(QEMUMachineInitArgs *args)
 
     sysmem = get_system_memory();
     dram = g_new(MemoryRegion, 1);
-    memory_region_init_ram(dram, "highbank.dram", ram_size);
+    memory_region_init_ram(dram, NULL, "highbank.dram", ram_size);
     /* SDRAM at address zero.  */
     memory_region_add_subregion(sysmem, 0, dram);
 
     sysram = g_new(MemoryRegion, 1);
-    memory_region_init_ram(sysram, "highbank.sysram", 0x8000);
+    memory_region_init_ram(sysram, NULL, "highbank.sysram", 0x8000);
     memory_region_add_subregion(sysmem, 0xfff88000, sysram);
     if (bios_name != NULL) {
         sysboot_filename = qemu_find_file(QEMU_FILE_TYPE_BIOS, bios_name);
diff --git a/hw/arm/integratorcp.c b/hw/arm/integratorcp.c
index cca2971..436d89b 100644
--- a/hw/arm/integratorcp.c
+++ b/hw/arm/integratorcp.c
@@ -249,10 +249,10 @@ static int integratorcm_init(SysBusDevice *dev)
     }
     memcpy(integrator_spd + 73, "QEMU-MEMORY", 11);
     s->cm_init = 0x00000112;
-    memory_region_init_ram(&s->flash, "integrator.flash", 0x100000);
+    memory_region_init_ram(&s->flash, NULL, "integrator.flash", 0x100000);
     vmstate_register_ram_global(&s->flash);
 
-    memory_region_init_io(&s->iomem, &integratorcm_ops, s,
+    memory_region_init_io(&s->iomem, NULL, &integratorcm_ops, s,
                           "integratorcm", 0x00800000);
     sysbus_init_mmio(dev, &s->iomem);
 
@@ -374,7 +374,7 @@ static int icp_pic_init(SysBusDevice *dev)
     qdev_init_gpio_in(&dev->qdev, icp_pic_set_irq, 32);
     sysbus_init_irq(dev, &s->parent_irq);
     sysbus_init_irq(dev, &s->parent_fiq);
-    memory_region_init_io(&s->iomem, &icp_pic_ops, s, "icp-pic", 0x00800000);
+    memory_region_init_io(&s->iomem, NULL, &icp_pic_ops, s, "icp-pic", 0x00800000);
     sysbus_init_mmio(dev, &s->iomem);
     return 0;
 }
@@ -424,7 +424,7 @@ static void icp_control_init(hwaddr base)
     MemoryRegion *io;
 
     io = (MemoryRegion *)g_malloc0(sizeof(MemoryRegion));
-    memory_region_init_io(io, &icp_control_ops, NULL,
+    memory_region_init_io(io, NULL, &icp_control_ops, NULL,
                           "control", 0x00800000);
     memory_region_add_subregion(get_system_memory(), base, io);
     /* ??? Save/restore.  */
@@ -463,14 +463,14 @@ static void integratorcp_init(QEMUMachineInitArgs *args)
         exit(1);
     }
 
-    memory_region_init_ram(ram, "integrator.ram", ram_size);
+    memory_region_init_ram(ram, NULL, "integrator.ram", ram_size);
     vmstate_register_ram_global(ram);
     /* ??? On a real system the first 1Mb is mapped as SSRAM or boot flash.  */
     /* ??? RAM should repeat to fill physical memory space.  */
     /* SDRAM at address zero*/
     memory_region_add_subregion(address_space_mem, 0, ram);
     /* And again at address 0x80000000 */
-    memory_region_init_alias(ram_alias, "ram.alias", ram, 0, ram_size);
+    memory_region_init_alias(ram_alias, NULL, "ram.alias", ram, 0, ram_size);
     memory_region_add_subregion(address_space_mem, 0x80000000, ram_alias);
 
     dev = qdev_create(NULL, "integrator_core");
diff --git a/hw/arm/kzm.c b/hw/arm/kzm.c
index cf90f5d..bd6c05c 100644
--- a/hw/arm/kzm.c
+++ b/hw/arm/kzm.c
@@ -98,14 +98,14 @@ static void kzm_init(QEMUMachineInitArgs *args)
 
     /* On a real system, the first 16k is a `secure boot rom' */
 
-    memory_region_init_ram(ram, "kzm.ram", ram_size);
+    memory_region_init_ram(ram, NULL, "kzm.ram", ram_size);
     vmstate_register_ram_global(ram);
     memory_region_add_subregion(address_space_mem, KZM_RAMADDRESS, ram);
 
-    memory_region_init_alias(ram_alias, "ram.alias", ram, 0, ram_size);
+    memory_region_init_alias(ram_alias, NULL, "ram.alias", ram, 0, ram_size);
     memory_region_add_subregion(address_space_mem, 0x88000000, ram_alias);
 
-    memory_region_init_ram(sram, "kzm.sram", 0x4000);
+    memory_region_init_ram(sram, NULL, "kzm.sram", 0x4000);
     memory_region_add_subregion(address_space_mem, 0x1FFFC000, sram);
 
     cpu_pic = arm_pic_init_cpu(cpu);
diff --git a/hw/arm/mainstone.c b/hw/arm/mainstone.c
index 260e314..8e5fc26 100644
--- a/hw/arm/mainstone.c
+++ b/hw/arm/mainstone.c
@@ -113,7 +113,7 @@ static void mainstone_common_init(MemoryRegion *address_space_mem,
 
     /* Setup CPU & memory */
     mpu = pxa270_init(address_space_mem, mainstone_binfo.ram_size, cpu_model);
-    memory_region_init_ram(rom, "mainstone.rom", MAINSTONE_ROM);
+    memory_region_init_ram(rom, NULL, "mainstone.rom", MAINSTONE_ROM);
     vmstate_register_ram_global(rom);
     memory_region_set_readonly(rom, true);
     memory_region_add_subregion(address_space_mem, 0, rom);
diff --git a/hw/arm/musicpal.c b/hw/arm/musicpal.c
index fbaf2be..bca8fdf 100644
--- a/hw/arm/musicpal.c
+++ b/hw/arm/musicpal.c
@@ -389,7 +389,7 @@ static int mv88w8618_eth_init(SysBusDevice *dev)
     sysbus_init_irq(dev, &s->irq);
     s->nic = qemu_new_nic(&net_mv88w8618_info, &s->conf,
                           object_get_typename(OBJECT(dev)), dev->qdev.id, s);
-    memory_region_init_io(&s->iomem, &mv88w8618_eth_ops, s, "mv88w8618-eth",
+    memory_region_init_io(&s->iomem, NULL, &mv88w8618_eth_ops, s, "mv88w8618-eth",
                           MP_ETH_SIZE);
     sysbus_init_mmio(dev, &s->iomem);
     return 0;
@@ -612,7 +612,7 @@ static int musicpal_lcd_init(SysBusDevice *dev)
 
     s->brightness = 7;
 
-    memory_region_init_io(&s->iomem, &musicpal_lcd_ops, s,
+    memory_region_init_io(&s->iomem, NULL, &musicpal_lcd_ops, s,
                           "musicpal-lcd", MP_LCD_SIZE);
     sysbus_init_mmio(dev, &s->iomem);
 
@@ -740,7 +740,7 @@ static int mv88w8618_pic_init(SysBusDevice *dev)
 
     qdev_init_gpio_in(&dev->qdev, mv88w8618_pic_set_irq, 32);
     sysbus_init_irq(dev, &s->parent_irq);
-    memory_region_init_io(&s->iomem, &mv88w8618_pic_ops, s,
+    memory_region_init_io(&s->iomem, NULL, &mv88w8618_pic_ops, s,
                           "musicpal-pic", MP_PIC_SIZE);
     sysbus_init_mmio(dev, &s->iomem);
     return 0;
@@ -905,7 +905,7 @@ static int mv88w8618_pit_init(SysBusDevice *dev)
         mv88w8618_timer_init(dev, &s->timer[i], 1000000);
     }
 
-    memory_region_init_io(&s->iomem, &mv88w8618_pit_ops, s,
+    memory_region_init_io(&s->iomem, NULL, &mv88w8618_pit_ops, s,
                           "musicpal-pit", MP_PIT_SIZE);
     sysbus_init_mmio(dev, &s->iomem);
     return 0;
@@ -999,7 +999,7 @@ static int mv88w8618_flashcfg_init(SysBusDevice *dev)
     mv88w8618_flashcfg_state *s = FROM_SYSBUS(mv88w8618_flashcfg_state, dev);
 
     s->cfgr0 = 0xfffe4285; /* Default as set by U-Boot for 8 MB flash */
-    memory_region_init_io(&s->iomem, &mv88w8618_flashcfg_ops, s,
+    memory_region_init_io(&s->iomem, NULL, &mv88w8618_flashcfg_ops, s,
                           "musicpal-flashcfg", MP_FLASHCFG_SIZE);
     sysbus_init_mmio(dev, &s->iomem);
     return 0;
@@ -1074,7 +1074,7 @@ static void musicpal_misc_init(Object *obj)
     SysBusDevice *sd = SYS_BUS_DEVICE(obj);
     MusicPalMiscState *s = MUSICPAL_MISC(obj);
 
-    memory_region_init_io(&s->iomem, &musicpal_misc_ops, NULL,
+    memory_region_init_io(&s->iomem, NULL, &musicpal_misc_ops, NULL,
                           "musicpal-misc", MP_MISC_SIZE);
     sysbus_init_mmio(sd, &s->iomem);
 }
@@ -1121,7 +1121,7 @@ static int mv88w8618_wlan_init(SysBusDevice *dev)
 {
     MemoryRegion *iomem = g_new(MemoryRegion, 1);
 
-    memory_region_init_io(iomem, &mv88w8618_wlan_ops, NULL,
+    memory_region_init_io(iomem, NULL, &mv88w8618_wlan_ops, NULL,
                           "musicpal-wlan", MP_WLAN_SIZE);
     sysbus_init_mmio(dev, iomem);
     return 0;
@@ -1327,7 +1327,7 @@ static int musicpal_gpio_init(SysBusDevice *dev)
 
     sysbus_init_irq(dev, &s->irq);
 
-    memory_region_init_io(&s->iomem, &musicpal_gpio_ops, s,
+    memory_region_init_io(&s->iomem, NULL, &musicpal_gpio_ops, s,
                           "musicpal-gpio", MP_GPIO_SIZE);
     sysbus_init_mmio(dev, &s->iomem);
 
@@ -1484,7 +1484,7 @@ static int musicpal_key_init(SysBusDevice *dev)
 {
     musicpal_key_state *s = FROM_SYSBUS(musicpal_key_state, dev);
 
-    memory_region_init(&s->iomem, "dummy", 0);
+    memory_region_init(&s->iomem, NULL, "dummy", 0);
     sysbus_init_mmio(dev, &s->iomem);
 
     s->kbd_extended = 0;
@@ -1564,11 +1564,11 @@ static void musicpal_init(QEMUMachineInitArgs *args)
     cpu_pic = arm_pic_init_cpu(cpu);
 
     /* For now we use a fixed - the original - RAM size */
-    memory_region_init_ram(ram, "musicpal.ram", MP_RAM_DEFAULT_SIZE);
+    memory_region_init_ram(ram, NULL, "musicpal.ram", MP_RAM_DEFAULT_SIZE);
     vmstate_register_ram_global(ram);
     memory_region_add_subregion(address_space_mem, 0, ram);
 
-    memory_region_init_ram(sram, "musicpal.sram", MP_SRAM_SIZE);
+    memory_region_init_ram(sram, NULL, "musicpal.sram", MP_SRAM_SIZE);
     vmstate_register_ram_global(sram);
     memory_region_add_subregion(address_space_mem, MP_SRAM_BASE, sram);
 
diff --git a/hw/arm/omap1.c b/hw/arm/omap1.c
index c06c642..19be5fc 100644
--- a/hw/arm/omap1.c
+++ b/hw/arm/omap1.c
@@ -264,7 +264,7 @@ static struct omap_mpu_timer_s *omap_mpu_timer_init(MemoryRegion *system_memory,
     omap_mpu_timer_reset(s);
     omap_timer_clk_setup(s);
 
-    memory_region_init_io(&s->iomem, &omap_mpu_timer_ops, s,
+    memory_region_init_io(&s->iomem, NULL, &omap_mpu_timer_ops, s,
                           "omap-mpu-timer", 0x100);
 
     memory_region_add_subregion(system_memory, base, &s->iomem);
@@ -392,7 +392,7 @@ static struct omap_watchdog_timer_s *omap_wd_timer_init(MemoryRegion *memory,
     omap_wd_timer_reset(s);
     omap_timer_clk_setup(&s->timer);
 
-    memory_region_init_io(&s->iomem, &omap_wd_timer_ops, s,
+    memory_region_init_io(&s->iomem, NULL, &omap_wd_timer_ops, s,
                           "omap-wd-timer", 0x100);
     memory_region_add_subregion(memory, base, &s->iomem);
 
@@ -498,7 +498,7 @@ static struct omap_32khz_timer_s *omap_os_timer_init(MemoryRegion *memory,
     omap_os_timer_reset(s);
     omap_timer_clk_setup(&s->timer);
 
-    memory_region_init_io(&s->iomem, &omap_os_timer_ops, s,
+    memory_region_init_io(&s->iomem, NULL, &omap_os_timer_ops, s,
                           "omap-os-timer", 0x800);
     memory_region_add_subregion(memory, base, &s->iomem);
 
@@ -731,7 +731,7 @@ static void omap_ulpd_pm_init(MemoryRegion *system_memory,
                 hwaddr base,
                 struct omap_mpu_state_s *mpu)
 {
-    memory_region_init_io(&mpu->ulpd_pm_iomem, &omap_ulpd_pm_ops, mpu,
+    memory_region_init_io(&mpu->ulpd_pm_iomem, NULL, &omap_ulpd_pm_ops, mpu,
                           "omap-ulpd-pm", 0x800);
     memory_region_add_subregion(system_memory, base, &mpu->ulpd_pm_iomem);
     omap_ulpd_pm_reset(mpu);
@@ -949,7 +949,7 @@ static void omap_pin_cfg_init(MemoryRegion *system_memory,
                 hwaddr base,
                 struct omap_mpu_state_s *mpu)
 {
-    memory_region_init_io(&mpu->pin_cfg_iomem, &omap_pin_cfg_ops, mpu,
+    memory_region_init_io(&mpu->pin_cfg_iomem, NULL, &omap_pin_cfg_ops, mpu,
                           "omap-pin-cfg", 0x800);
     memory_region_add_subregion(system_memory, base, &mpu->pin_cfg_iomem);
     omap_pin_cfg_reset(mpu);
@@ -1021,16 +1021,16 @@ static const MemoryRegionOps omap_id_ops = {
 
 static void omap_id_init(MemoryRegion *memory, struct omap_mpu_state_s *mpu)
 {
-    memory_region_init_io(&mpu->id_iomem, &omap_id_ops, mpu,
+    memory_region_init_io(&mpu->id_iomem, NULL, &omap_id_ops, mpu,
                           "omap-id", 0x100000000ULL);
-    memory_region_init_alias(&mpu->id_iomem_e18, "omap-id-e18", &mpu->id_iomem,
+    memory_region_init_alias(&mpu->id_iomem_e18, NULL, "omap-id-e18", &mpu->id_iomem,
                              0xfffe1800, 0x800);
     memory_region_add_subregion(memory, 0xfffe1800, &mpu->id_iomem_e18);
-    memory_region_init_alias(&mpu->id_iomem_ed4, "omap-id-ed4", &mpu->id_iomem,
+    memory_region_init_alias(&mpu->id_iomem_ed4, NULL, "omap-id-ed4", &mpu->id_iomem,
                              0xfffed400, 0x100);
     memory_region_add_subregion(memory, 0xfffed400, &mpu->id_iomem_ed4);
     if (!cpu_is_omap15xx(mpu)) {
-        memory_region_init_alias(&mpu->id_iomem_ed4, "omap-id-e20",
+        memory_region_init_alias(&mpu->id_iomem_ed4, NULL, "omap-id-e20",
                                  &mpu->id_iomem, 0xfffe2000, 0x800);
         memory_region_add_subregion(memory, 0xfffe2000, &mpu->id_iomem_e20);
     }
@@ -1115,7 +1115,7 @@ static void omap_mpui_reset(struct omap_mpu_state_s *s)
 static void omap_mpui_init(MemoryRegion *memory, hwaddr base,
                 struct omap_mpu_state_s *mpu)
 {
-    memory_region_init_io(&mpu->mpui_iomem, &omap_mpui_ops, mpu,
+    memory_region_init_io(&mpu->mpui_iomem, NULL, &omap_mpui_ops, mpu,
                           "omap-mpui", 0x100);
     memory_region_add_subregion(memory, base, &mpu->mpui_iomem);
 
@@ -1227,7 +1227,7 @@ static struct omap_tipb_bridge_s *omap_tipb_bridge_init(
     s->abort = abort_irq;
     omap_tipb_bridge_reset(s);
 
-    memory_region_init_io(&s->iomem, &omap_tipb_bridge_ops, s,
+    memory_region_init_io(&s->iomem, NULL, &omap_tipb_bridge_ops, s,
                           "omap-tipb-bridge", 0x100);
     memory_region_add_subregion(memory, base, &s->iomem);
 
@@ -1336,7 +1336,7 @@ static void omap_tcmi_reset(struct omap_mpu_state_s *mpu)
 static void omap_tcmi_init(MemoryRegion *memory, hwaddr base,
                 struct omap_mpu_state_s *mpu)
 {
-    memory_region_init_io(&mpu->tcmi_iomem, &omap_tcmi_ops, mpu,
+    memory_region_init_io(&mpu->tcmi_iomem, NULL, &omap_tcmi_ops, mpu,
                           "omap-tcmi", 0x100);
     memory_region_add_subregion(memory, base, &mpu->tcmi_iomem);
     omap_tcmi_reset(mpu);
@@ -1418,7 +1418,7 @@ static struct dpll_ctl_s  *omap_dpll_init(MemoryRegion *memory,
                            hwaddr base, omap_clk clk)
 {
     struct dpll_ctl_s *s = g_malloc0(sizeof(*s));
-    memory_region_init_io(&s->iomem, &omap_dpll_ops, s, "omap-dpll", 0x100);
+    memory_region_init_io(&s->iomem, NULL, &omap_dpll_ops, s, "omap-dpll", 0x100);
 
     s->dpll = clk;
     omap_dpll_reset(s);
@@ -1831,9 +1831,9 @@ static void omap_clkm_reset(struct omap_mpu_state_s *s)
 static void omap_clkm_init(MemoryRegion *memory, hwaddr mpu_base,
                 hwaddr dsp_base, struct omap_mpu_state_s *s)
 {
-    memory_region_init_io(&s->clkm_iomem, &omap_clkm_ops, s,
+    memory_region_init_io(&s->clkm_iomem, NULL, &omap_clkm_ops, s,
                           "omap-clkm", 0x100);
-    memory_region_init_io(&s->clkdsp_iomem, &omap_clkdsp_ops, s,
+    memory_region_init_io(&s->clkdsp_iomem, NULL, &omap_clkdsp_ops, s,
                           "omap-clkdsp", 0x1000);
 
     s->clkm.arm_idlect1 = 0x03ff;
@@ -2090,7 +2090,7 @@ static struct omap_mpuio_s *omap_mpuio_init(MemoryRegion *memory,
     s->in = qemu_allocate_irqs(omap_mpuio_set, s, 16);
     omap_mpuio_reset(s);
 
-    memory_region_init_io(&s->iomem, &omap_mpuio_ops, s,
+    memory_region_init_io(&s->iomem, NULL, &omap_mpuio_ops, s,
                           "omap-mpuio", 0x800);
     memory_region_add_subregion(memory, base, &s->iomem);
 
@@ -2281,7 +2281,7 @@ static struct omap_uwire_s *omap_uwire_init(MemoryRegion *system_memory,
     s->txdrq = dma;
     omap_uwire_reset(s);
 
-    memory_region_init_io(&s->iomem, &omap_uwire_ops, s, "omap-uwire", 0x800);
+    memory_region_init_io(&s->iomem, NULL, &omap_uwire_ops, s, "omap-uwire", 0x800);
     memory_region_add_subregion(system_memory, base, &s->iomem);
 
     return s;
@@ -2393,7 +2393,7 @@ static struct omap_pwl_s *omap_pwl_init(MemoryRegion *system_memory,
 
     omap_pwl_reset(s);
 
-    memory_region_init_io(&s->iomem, &omap_pwl_ops, s,
+    memory_region_init_io(&s->iomem, NULL, &omap_pwl_ops, s,
                           "omap-pwl", 0x800);
     memory_region_add_subregion(system_memory, base, &s->iomem);
 
@@ -2500,7 +2500,7 @@ static struct omap_pwt_s *omap_pwt_init(MemoryRegion *system_memory,
     s->clk = clk;
     omap_pwt_reset(s);
 
-    memory_region_init_io(&s->iomem, &omap_pwt_ops, s,
+    memory_region_init_io(&s->iomem, NULL, &omap_pwt_ops, s,
                           "omap-pwt", 0x800);
     memory_region_add_subregion(system_memory, base, &s->iomem);
     return s;
@@ -2919,7 +2919,7 @@ static struct omap_rtc_s *omap_rtc_init(MemoryRegion *system_memory,
 
     omap_rtc_reset(s);
 
-    memory_region_init_io(&s->iomem, &omap_rtc_ops, s,
+    memory_region_init_io(&s->iomem, NULL, &omap_rtc_ops, s,
                           "omap-rtc", 0x800);
     memory_region_add_subregion(system_memory, base, &s->iomem);
 
@@ -3452,7 +3452,7 @@ static struct omap_mcbsp_s *omap_mcbsp_init(MemoryRegion *system_memory,
     s->source_timer = qemu_new_timer_ns(vm_clock, omap_mcbsp_source_tick, s);
     omap_mcbsp_reset(s);
 
-    memory_region_init_io(&s->iomem, &omap_mcbsp_ops, s, "omap-mcbsp", 0x800);
+    memory_region_init_io(&s->iomem, NULL, &omap_mcbsp_ops, s, "omap-mcbsp", 0x800);
     memory_region_add_subregion(system_memory, base, &s->iomem);
 
     return s;
@@ -3627,7 +3627,7 @@ static struct omap_lpg_s *omap_lpg_init(MemoryRegion *system_memory,
 
     omap_lpg_reset(s);
 
-    memory_region_init_io(&s->iomem, &omap_lpg_ops, s, "omap-lpg", 0x800);
+    memory_region_init_io(&s->iomem, NULL, &omap_lpg_ops, s, "omap-lpg", 0x800);
     memory_region_add_subregion(system_memory, base, &s->iomem);
 
     omap_clk_adduser(clk, qemu_allocate_irqs(omap_lpg_clk_update, s, 1)[0]);
@@ -3666,7 +3666,7 @@ static const MemoryRegionOps omap_mpui_io_ops = {
 static void omap_setup_mpui_io(MemoryRegion *system_memory,
                                struct omap_mpu_state_s *mpu)
 {
-    memory_region_init_io(&mpu->mpui_io_iomem, &omap_mpui_io_ops, mpu,
+    memory_region_init_io(&mpu->mpui_io_iomem, NULL, &omap_mpui_io_ops, mpu,
                           "omap-mpui-io", 0x7fff);
     memory_region_add_subregion(system_memory, OMAP_MPUI_BASE,
                                 &mpu->mpui_io_iomem);
@@ -3747,7 +3747,7 @@ static void omap_setup_dsp_mapping(MemoryRegion *system_memory,
 
     for (; map->phys_dsp; map ++) {
         io = g_new(MemoryRegion, 1);
-        memory_region_init_alias(io, map->name,
+        memory_region_init_alias(io, NULL, map->name,
                                  system_memory, map->phys_mpu, map->size);
         memory_region_add_subregion(system_memory, map->phys_dsp, io);
     }
@@ -3851,10 +3851,10 @@ struct omap_mpu_state_s *omap310_mpu_init(MemoryRegion *system_memory,
     omap_clk_init(s);
 
     /* Memory-mapped stuff */
-    memory_region_init_ram(&s->emiff_ram, "omap1.dram", s->sdram_size);
+    memory_region_init_ram(&s->emiff_ram, NULL, "omap1.dram", s->sdram_size);
     vmstate_register_ram_global(&s->emiff_ram);
     memory_region_add_subregion(system_memory, OMAP_EMIFF_BASE, &s->emiff_ram);
-    memory_region_init_ram(&s->imif_ram, "omap1.sram", s->sram_size);
+    memory_region_init_ram(&s->imif_ram, NULL, "omap1.sram", s->sram_size);
     vmstate_register_ram_global(&s->imif_ram);
     memory_region_add_subregion(system_memory, OMAP_IMIF_BASE, &s->imif_ram);
 
diff --git a/hw/arm/omap2.c b/hw/arm/omap2.c
index 2ff4371..ec9610b 100644
--- a/hw/arm/omap2.c
+++ b/hw/arm/omap2.c
@@ -603,7 +603,7 @@ static struct omap_eac_s *omap_eac_init(struct omap_target_agent_s *ta,
 
     AUD_register_card("OMAP EAC", &s->codec.card);
 
-    memory_region_init_io(&s->iomem, &omap_eac_ops, s, "omap.eac",
+    memory_region_init_io(&s->iomem, NULL, &omap_eac_ops, s, "omap.eac",
                           omap_l4_region_size(ta, 0));
     omap_l4_attach(ta, 0, &s->iomem);
 
@@ -791,11 +791,11 @@ static struct omap_sti_s *omap_sti_init(struct omap_target_agent_s *ta,
 
     s->chr = chr ?: qemu_chr_new("null", "null", NULL);
 
-    memory_region_init_io(&s->iomem, &omap_sti_ops, s, "omap.sti",
+    memory_region_init_io(&s->iomem, NULL, &omap_sti_ops, s, "omap.sti",
                           omap_l4_region_size(ta, 0));
     omap_l4_attach(ta, 0, &s->iomem);
 
-    memory_region_init_io(&s->iomem_fifo, &omap_sti_fifo_ops, s,
+    memory_region_init_io(&s->iomem_fifo, NULL, &omap_sti_fifo_ops, s,
                           "omap.sti.fifo", 0x10000);
     memory_region_add_subregion(sysmem, channel_base, &s->iomem_fifo);
 
@@ -1809,9 +1809,9 @@ static struct omap_prcm_s *omap_prcm_init(struct omap_target_agent_s *ta,
     s->mpu = mpu;
     omap_prcm_coldreset(s);
 
-    memory_region_init_io(&s->iomem0, &omap_prcm_ops, s, "omap.pcrm0",
+    memory_region_init_io(&s->iomem0, NULL, &omap_prcm_ops, s, "omap.pcrm0",
                           omap_l4_region_size(ta, 0));
-    memory_region_init_io(&s->iomem1, &omap_prcm_ops, s, "omap.pcrm1",
+    memory_region_init_io(&s->iomem1, NULL, &omap_prcm_ops, s, "omap.pcrm1",
                           omap_l4_region_size(ta, 1));
     omap_l4_attach(ta, 0, &s->iomem0);
     omap_l4_attach(ta, 1, &s->iomem1);
@@ -2185,7 +2185,7 @@ static struct omap_sysctl_s *omap_sysctl_init(struct omap_target_agent_s *ta,
     s->mpu = mpu;
     omap_sysctl_reset(s);
 
-    memory_region_init_io(&s->iomem, &omap_sysctl_ops, s, "omap.sysctl",
+    memory_region_init_io(&s->iomem, NULL, &omap_sysctl_ops, s, "omap.sysctl",
                           omap_l4_region_size(ta, 0));
     omap_l4_attach(ta, 0, &s->iomem);
 
@@ -2267,10 +2267,10 @@ struct omap_mpu_state_s *omap2420_mpu_init(MemoryRegion *sysmem,
     omap_clk_init(s);
 
     /* Memory-mapped stuff */
-    memory_region_init_ram(&s->sdram, "omap2.dram", s->sdram_size);
+    memory_region_init_ram(&s->sdram, NULL, "omap2.dram", s->sdram_size);
     vmstate_register_ram_global(&s->sdram);
     memory_region_add_subregion(sysmem, OMAP2_Q2_BASE, &s->sdram);
-    memory_region_init_ram(&s->sram, "omap2.sram", s->sram_size);
+    memory_region_init_ram(&s->sram, NULL, "omap2.sram", s->sram_size);
     vmstate_register_ram_global(&s->sram);
     memory_region_add_subregion(sysmem, OMAP2_SRAM_BASE, &s->sram);
 
diff --git a/hw/arm/omap_sx1.c b/hw/arm/omap_sx1.c
index e421ece..05b0353 100644
--- a/hw/arm/omap_sx1.c
+++ b/hw/arm/omap_sx1.c
@@ -120,23 +120,23 @@ static void sx1_init(QEMUMachineInitArgs *args, const int version)
     mpu = omap310_mpu_init(address_space, sx1_binfo.ram_size, args->cpu_model);
 
     /* External Flash (EMIFS) */
-    memory_region_init_ram(flash, "omap_sx1.flash0-0", flash_size);
+    memory_region_init_ram(flash, NULL, "omap_sx1.flash0-0", flash_size);
     vmstate_register_ram_global(flash);
     memory_region_set_readonly(flash, true);
     memory_region_add_subregion(address_space, OMAP_CS0_BASE, flash);
 
-    memory_region_init_io(&cs[0], &static_ops, &cs0val,
+    memory_region_init_io(&cs[0], NULL, &static_ops, &cs0val,
                           "sx1.cs0", OMAP_CS0_SIZE - flash_size);
     memory_region_add_subregion(address_space,
                                 OMAP_CS0_BASE + flash_size, &cs[0]);
 
 
-    memory_region_init_io(&cs[2], &static_ops, &cs2val,
+    memory_region_init_io(&cs[2], NULL, &static_ops, &cs2val,
                           "sx1.cs2", OMAP_CS2_SIZE);
     memory_region_add_subregion(address_space,
                                 OMAP_CS2_BASE, &cs[2]);
 
-    memory_region_init_io(&cs[3], &static_ops, &cs3val,
+    memory_region_init_io(&cs[3], NULL, &static_ops, &cs3val,
                           "sx1.cs3", OMAP_CS3_SIZE);
     memory_region_add_subregion(address_space,
                                 OMAP_CS2_BASE, &cs[3]);
@@ -162,12 +162,12 @@ static void sx1_init(QEMUMachineInitArgs *args, const int version)
 
     if ((version == 1) &&
             (dinfo = drive_get(IF_PFLASH, 0, fl_idx)) != NULL) {
-        memory_region_init_ram(flash_1, "omap_sx1.flash1-0", flash1_size);
+        memory_region_init_ram(flash_1, NULL, "omap_sx1.flash1-0", flash1_size);
         vmstate_register_ram_global(flash_1);
         memory_region_set_readonly(flash_1, true);
         memory_region_add_subregion(address_space, OMAP_CS1_BASE, flash_1);
 
-        memory_region_init_io(&cs[1], &static_ops, &cs1val,
+        memory_region_init_io(&cs[1], NULL, &static_ops, &cs1val,
                               "sx1.cs1", OMAP_CS1_SIZE - flash1_size);
         memory_region_add_subregion(address_space,
                                 OMAP_CS1_BASE + flash1_size, &cs[1]);
@@ -182,7 +182,7 @@ static void sx1_init(QEMUMachineInitArgs *args, const int version)
         }
         fl_idx++;
     } else {
-        memory_region_init_io(&cs[1], &static_ops, &cs1val,
+        memory_region_init_io(&cs[1], NULL, &static_ops, &cs1val,
                               "sx1.cs1", OMAP_CS1_SIZE);
         memory_region_add_subregion(address_space,
                                 OMAP_CS1_BASE, &cs[1]);
diff --git a/hw/arm/palm.c b/hw/arm/palm.c
index b13d810..cdc3c3a 100644
--- a/hw/arm/palm.c
+++ b/hw/arm/palm.c
@@ -211,22 +211,22 @@ static void palmte_init(QEMUMachineInitArgs *args)
     mpu = omap310_mpu_init(address_space_mem, sdram_size, cpu_model);
 
     /* External Flash (EMIFS) */
-    memory_region_init_ram(flash, "palmte.flash", flash_size);
+    memory_region_init_ram(flash, NULL, "palmte.flash", flash_size);
     vmstate_register_ram_global(flash);
     memory_region_set_readonly(flash, true);
     memory_region_add_subregion(address_space_mem, OMAP_CS0_BASE, flash);
 
-    memory_region_init_io(&cs[0], &static_ops, &cs0val, "palmte-cs0",
+    memory_region_init_io(&cs[0], NULL, &static_ops, &cs0val, "palmte-cs0",
                           OMAP_CS0_SIZE - flash_size);
     memory_region_add_subregion(address_space_mem, OMAP_CS0_BASE + flash_size,
                                 &cs[0]);
-    memory_region_init_io(&cs[1], &static_ops, &cs1val, "palmte-cs1",
+    memory_region_init_io(&cs[1], NULL, &static_ops, &cs1val, "palmte-cs1",
                           OMAP_CS1_SIZE);
     memory_region_add_subregion(address_space_mem, OMAP_CS1_BASE, &cs[1]);
-    memory_region_init_io(&cs[2], &static_ops, &cs2val, "palmte-cs2",
+    memory_region_init_io(&cs[2], NULL, &static_ops, &cs2val, "palmte-cs2",
                           OMAP_CS2_SIZE);
     memory_region_add_subregion(address_space_mem, OMAP_CS2_BASE, &cs[2]);
-    memory_region_init_io(&cs[3], &static_ops, &cs3val, "palmte-cs3",
+    memory_region_init_io(&cs[3], NULL, &static_ops, &cs3val, "palmte-cs3",
                           OMAP_CS3_SIZE);
     memory_region_add_subregion(address_space_mem, OMAP_CS3_BASE, &cs[3]);
 
diff --git a/hw/arm/pxa2xx.c b/hw/arm/pxa2xx.c
index 24b03a0..d046edc 100644
--- a/hw/arm/pxa2xx.c
+++ b/hw/arm/pxa2xx.c
@@ -764,7 +764,7 @@ static int pxa2xx_ssp_init(SysBusDevice *dev)
 
     sysbus_init_irq(dev, &s->irq);
 
-    memory_region_init_io(&s->iomem, &pxa2xx_ssp_ops, s, "pxa2xx-ssp", 0x1000);
+    memory_region_init_io(&s->iomem, NULL, &pxa2xx_ssp_ops, s, "pxa2xx-ssp", 0x1000);
     sysbus_init_mmio(dev, &s->iomem);
     register_savevm(&dev->qdev, "pxa2xx_ssp", -1, 0,
                     pxa2xx_ssp_save, pxa2xx_ssp_load, s);
@@ -1131,7 +1131,7 @@ static int pxa2xx_rtc_init(SysBusDevice *dev)
 
     sysbus_init_irq(dev, &s->rtc_irq);
 
-    memory_region_init_io(&s->iomem, &pxa2xx_rtc_ops, s, "pxa2xx-rtc", 0x10000);
+    memory_region_init_io(&s->iomem, NULL, &pxa2xx_rtc_ops, s, "pxa2xx-rtc", 0x10000);
     sysbus_init_mmio(dev, &s->iomem);
 
     return 0;
@@ -1481,7 +1481,7 @@ static int pxa2xx_i2c_initfn(SysBusDevice *dev)
 
     s->bus = i2c_init_bus(&dev->qdev, "i2c");
 
-    memory_region_init_io(&s->iomem, &pxa2xx_i2c_ops, s,
+    memory_region_init_io(&s->iomem, NULL, &pxa2xx_i2c_ops, s,
                           "pxa2xx-i2x", s->region_size);
     sysbus_init_mmio(dev, &s->iomem);
     sysbus_init_irq(dev, &s->irq);
@@ -1720,7 +1720,7 @@ static PXA2xxI2SState *pxa2xx_i2s_init(MemoryRegion *sysmem,
 
     pxa2xx_i2s_reset(s);
 
-    memory_region_init_io(&s->iomem, &pxa2xx_i2s_ops, s,
+    memory_region_init_io(&s->iomem, NULL, &pxa2xx_i2s_ops, s,
                           "pxa2xx-i2s", 0x100000);
     memory_region_add_subregion(sysmem, base, &s->iomem);
 
@@ -1978,7 +1978,7 @@ static PXA2xxFIrState *pxa2xx_fir_init(MemoryRegion *sysmem,
 
     pxa2xx_fir_reset(s);
 
-    memory_region_init_io(&s->iomem, &pxa2xx_fir_ops, s, "pxa2xx-fir", 0x1000);
+    memory_region_init_io(&s->iomem, NULL, &pxa2xx_fir_ops, s, "pxa2xx-fir", 0x1000);
     memory_region_add_subregion(sysmem, base, &s->iomem);
 
     if (chr) {
@@ -2027,10 +2027,10 @@ PXA2xxState *pxa270_init(MemoryRegion *address_space,
     s->reset = qemu_allocate_irqs(pxa2xx_reset, s, 1)[0];
 
     /* SDRAM & Internal Memory Storage */
-    memory_region_init_ram(&s->sdram, "pxa270.sdram", sdram_size);
+    memory_region_init_ram(&s->sdram, NULL, "pxa270.sdram", sdram_size);
     vmstate_register_ram_global(&s->sdram);
     memory_region_add_subregion(address_space, PXA2XX_SDRAM_BASE, &s->sdram);
-    memory_region_init_ram(&s->internal, "pxa270.internal", 0x40000);
+    memory_region_init_ram(&s->internal, NULL, "pxa270.internal", 0x40000);
     vmstate_register_ram_global(&s->internal);
     memory_region_add_subregion(address_space, PXA2XX_INTERNAL_BASE,
                                 &s->internal);
@@ -2083,7 +2083,7 @@ PXA2xxState *pxa270_init(MemoryRegion *address_space,
     s->cm_base = 0x41300000;
     s->cm_regs[CCCR >> 2] = 0x02000210;	/* 416.0 MHz */
     s->clkcfg = 0x00000009;		/* Turbo mode active */
-    memory_region_init_io(&s->cm_iomem, &pxa2xx_cm_ops, s, "pxa2xx-cm", 0x1000);
+    memory_region_init_io(&s->cm_iomem, NULL, &pxa2xx_cm_ops, s, "pxa2xx-cm", 0x1000);
     memory_region_add_subregion(address_space, s->cm_base, &s->cm_iomem);
     vmstate_register(NULL, 0, &vmstate_pxa2xx_cm, s);
 
@@ -2093,12 +2093,12 @@ PXA2xxState *pxa270_init(MemoryRegion *address_space,
     s->mm_regs[MDMRS >> 2] = 0x00020002;
     s->mm_regs[MDREFR >> 2] = 0x03ca4000;
     s->mm_regs[MECR >> 2] = 0x00000001;	/* Two PC Card sockets */
-    memory_region_init_io(&s->mm_iomem, &pxa2xx_mm_ops, s, "pxa2xx-mm", 0x1000);
+    memory_region_init_io(&s->mm_iomem, NULL, &pxa2xx_mm_ops, s, "pxa2xx-mm", 0x1000);
     memory_region_add_subregion(address_space, s->mm_base, &s->mm_iomem);
     vmstate_register(NULL, 0, &vmstate_pxa2xx_mm, s);
 
     s->pm_base = 0x40f00000;
-    memory_region_init_io(&s->pm_iomem, &pxa2xx_pm_ops, s, "pxa2xx-pm", 0x100);
+    memory_region_init_io(&s->pm_iomem, NULL, &pxa2xx_pm_ops, s, "pxa2xx-pm", 0x100);
     memory_region_add_subregion(address_space, s->pm_base, &s->pm_iomem);
     vmstate_register(NULL, 0, &vmstate_pxa2xx_pm, s);
 
@@ -2158,10 +2158,10 @@ PXA2xxState *pxa255_init(MemoryRegion *address_space, unsigned int sdram_size)
     s->reset = qemu_allocate_irqs(pxa2xx_reset, s, 1)[0];
 
     /* SDRAM & Internal Memory Storage */
-    memory_region_init_ram(&s->sdram, "pxa255.sdram", sdram_size);
+    memory_region_init_ram(&s->sdram, NULL, "pxa255.sdram", sdram_size);
     vmstate_register_ram_global(&s->sdram);
     memory_region_add_subregion(address_space, PXA2XX_SDRAM_BASE, &s->sdram);
-    memory_region_init_ram(&s->internal, "pxa255.internal",
+    memory_region_init_ram(&s->internal, NULL, "pxa255.internal",
                            PXA2XX_INTERNAL_SIZE);
     vmstate_register_ram_global(&s->internal);
     memory_region_add_subregion(address_space, PXA2XX_INTERNAL_BASE,
@@ -2214,7 +2214,7 @@ PXA2xxState *pxa255_init(MemoryRegion *address_space, unsigned int sdram_size)
     s->cm_base = 0x41300000;
     s->cm_regs[CCCR >> 2] = 0x02000210;	/* 416.0 MHz */
     s->clkcfg = 0x00000009;		/* Turbo mode active */
-    memory_region_init_io(&s->cm_iomem, &pxa2xx_cm_ops, s, "pxa2xx-cm", 0x1000);
+    memory_region_init_io(&s->cm_iomem, NULL, &pxa2xx_cm_ops, s, "pxa2xx-cm", 0x1000);
     memory_region_add_subregion(address_space, s->cm_base, &s->cm_iomem);
     vmstate_register(NULL, 0, &vmstate_pxa2xx_cm, s);
 
@@ -2224,12 +2224,12 @@ PXA2xxState *pxa255_init(MemoryRegion *address_space, unsigned int sdram_size)
     s->mm_regs[MDMRS >> 2] = 0x00020002;
     s->mm_regs[MDREFR >> 2] = 0x03ca4000;
     s->mm_regs[MECR >> 2] = 0x00000001;	/* Two PC Card sockets */
-    memory_region_init_io(&s->mm_iomem, &pxa2xx_mm_ops, s, "pxa2xx-mm", 0x1000);
+    memory_region_init_io(&s->mm_iomem, NULL, &pxa2xx_mm_ops, s, "pxa2xx-mm", 0x1000);
     memory_region_add_subregion(address_space, s->mm_base, &s->mm_iomem);
     vmstate_register(NULL, 0, &vmstate_pxa2xx_mm, s);
 
     s->pm_base = 0x40f00000;
-    memory_region_init_io(&s->pm_iomem, &pxa2xx_pm_ops, s, "pxa2xx-pm", 0x100);
+    memory_region_init_io(&s->pm_iomem, NULL, &pxa2xx_pm_ops, s, "pxa2xx-pm", 0x100);
     memory_region_add_subregion(address_space, s->pm_base, &s->pm_iomem);
     vmstate_register(NULL, 0, &vmstate_pxa2xx_pm, s);
 
diff --git a/hw/arm/pxa2xx_gpio.c b/hw/arm/pxa2xx_gpio.c
index fa31575..abf41dc 100644
--- a/hw/arm/pxa2xx_gpio.c
+++ b/hw/arm/pxa2xx_gpio.c
@@ -283,7 +283,7 @@ static int pxa2xx_gpio_initfn(SysBusDevice *dev)
     qdev_init_gpio_in(&dev->qdev, pxa2xx_gpio_set, s->lines);
     qdev_init_gpio_out(&dev->qdev, s->handler, s->lines);
 
-    memory_region_init_io(&s->iomem, &pxa_gpio_ops, s, "pxa2xx-gpio", 0x1000);
+    memory_region_init_io(&s->iomem, NULL, &pxa_gpio_ops, s, "pxa2xx-gpio", 0x1000);
     sysbus_init_mmio(dev, &s->iomem);
     sysbus_init_irq(dev, &s->irq0);
     sysbus_init_irq(dev, &s->irq1);
diff --git a/hw/arm/pxa2xx_pic.c b/hw/arm/pxa2xx_pic.c
index 835d07c..042d422 100644
--- a/hw/arm/pxa2xx_pic.c
+++ b/hw/arm/pxa2xx_pic.c
@@ -278,7 +278,7 @@ DeviceState *pxa2xx_pic_init(hwaddr base, ARMCPU *cpu)
     qdev_init_gpio_in(dev, pxa2xx_pic_set_irq, PXA2XX_PIC_SRCS);
 
     /* Enable IC memory-mapped registers access.  */
-    memory_region_init_io(&s->iomem, &pxa2xx_pic_ops, s,
+    memory_region_init_io(&s->iomem, NULL, &pxa2xx_pic_ops, s,
                           "pxa2xx-pic", 0x00100000);
     sysbus_init_mmio(SYS_BUS_DEVICE(dev), &s->iomem);
     sysbus_mmio_map(SYS_BUS_DEVICE(dev), 0, base);
diff --git a/hw/arm/realview.c b/hw/arm/realview.c
index d6f47bf..1e6c1dd 100644
--- a/hw/arm/realview.c
+++ b/hw/arm/realview.c
@@ -114,18 +114,18 @@ static void realview_init(QEMUMachineInitArgs *args,
         /* Core tile RAM.  */
         low_ram_size = ram_size - 0x20000000;
         ram_size = 0x20000000;
-        memory_region_init_ram(ram_lo, "realview.lowmem", low_ram_size);
+        memory_region_init_ram(ram_lo, NULL, "realview.lowmem", low_ram_size);
         vmstate_register_ram_global(ram_lo);
         memory_region_add_subregion(sysmem, 0x20000000, ram_lo);
     }
 
-    memory_region_init_ram(ram_hi, "realview.highmem", ram_size);
+    memory_region_init_ram(ram_hi, NULL, "realview.highmem", ram_size);
     vmstate_register_ram_global(ram_hi);
     low_ram_size = ram_size;
     if (low_ram_size > 0x10000000)
       low_ram_size = 0x10000000;
     /* SDRAM at address zero.  */
-    memory_region_init_alias(ram_alias, "realview.alias",
+    memory_region_init_alias(ram_alias, NULL, "realview.alias",
                              ram_hi, 0, low_ram_size);
     memory_region_add_subregion(sysmem, 0, ram_alias);
     if (is_pb) {
@@ -318,7 +318,7 @@ static void realview_init(QEMUMachineInitArgs *args,
        startup code.  I guess this works on real hardware because the
        BootROM happens to be in ROM/flash or in memory that isn't clobbered
        until after Linux boots the secondary CPUs.  */
-    memory_region_init_ram(ram_hack, "realview.hack", 0x1000);
+    memory_region_init_ram(ram_hack, NULL, "realview.hack", 0x1000);
     vmstate_register_ram_global(ram_hack);
     memory_region_add_subregion(sysmem, SMP_BOOT_ADDR, ram_hack);
 
diff --git a/hw/arm/spitz.c b/hw/arm/spitz.c
index b5ed109..60ad30d 100644
--- a/hw/arm/spitz.c
+++ b/hw/arm/spitz.c
@@ -169,7 +169,7 @@ static int sl_nand_init(SysBusDevice *dev) {
     nand = drive_get(IF_MTD, 0, 0);
     s->nand = nand_init(nand ? nand->bdrv : NULL, s->manf_id, s->chip_id);
 
-    memory_region_init_io(&s->iomem, &sl_ops, s, "sl", 0x40);
+    memory_region_init_io(&s->iomem, NULL, &sl_ops, s, "sl", 0x40);
     sysbus_init_mmio(dev, &s->iomem);
 
     return 0;
@@ -896,7 +896,7 @@ static void spitz_common_init(QEMUMachineInitArgs *args,
 
     sl_flash_register(mpu, (model == spitz) ? FLASH_128M : FLASH_1024M);
 
-    memory_region_init_ram(rom, "spitz.rom", SPITZ_ROM);
+    memory_region_init_ram(rom, NULL, "spitz.rom", SPITZ_ROM);
     vmstate_register_ram_global(rom);
     memory_region_set_readonly(rom, true);
     memory_region_add_subregion(address_space_mem, 0, rom);
diff --git a/hw/arm/stellaris.c b/hw/arm/stellaris.c
index 2b61e3c..30e7b76 100644
--- a/hw/arm/stellaris.c
+++ b/hw/arm/stellaris.c
@@ -307,7 +307,7 @@ static int stellaris_gptm_init(SysBusDevice *dev)
     sysbus_init_irq(dev, &s->irq);
     qdev_init_gpio_out(&dev->qdev, &s->trigger, 1);
 
-    memory_region_init_io(&s->iomem, &gptm_ops, s,
+    memory_region_init_io(&s->iomem, NULL, &gptm_ops, s,
                           "gptm", 0x1000);
     sysbus_init_mmio(dev, &s->iomem);
 
@@ -669,7 +669,7 @@ static int stellaris_sys_init(uint32_t base, qemu_irq irq,
     s->user0 = macaddr[0] | (macaddr[1] << 8) | (macaddr[2] << 16);
     s->user1 = macaddr[3] | (macaddr[4] << 8) | (macaddr[5] << 16);
 
-    memory_region_init_io(&s->iomem, &ssys_ops, s, "ssys", 0x00001000);
+    memory_region_init_io(&s->iomem, NULL, &ssys_ops, s, "ssys", 0x00001000);
     memory_region_add_subregion(get_system_memory(), base, &s->iomem);
     ssys_reset(s);
     vmstate_register(NULL, -1, &vmstate_stellaris_sys, s);
@@ -862,7 +862,7 @@ static int stellaris_i2c_init(SysBusDevice * dev)
     bus = i2c_init_bus(&dev->qdev, "i2c");
     s->bus = bus;
 
-    memory_region_init_io(&s->iomem, &stellaris_i2c_ops, s,
+    memory_region_init_io(&s->iomem, NULL, &stellaris_i2c_ops, s,
                           "i2c", 0x1000);
     sysbus_init_mmio(dev, &s->iomem);
     /* ??? For now we only implement the master interface.  */
@@ -1145,7 +1145,7 @@ static int stellaris_adc_init(SysBusDevice *dev)
         sysbus_init_irq(dev, &s->irq[n]);
     }
 
-    memory_region_init_io(&s->iomem, &stellaris_adc_ops, s,
+    memory_region_init_io(&s->iomem, NULL, &stellaris_adc_ops, s,
                           "adc", 0x1000);
     sysbus_init_mmio(dev, &s->iomem);
     stellaris_adc_reset(s);
diff --git a/hw/arm/strongarm.c b/hw/arm/strongarm.c
index 4d49306..0f5a545 100644
--- a/hw/arm/strongarm.c
+++ b/hw/arm/strongarm.c
@@ -173,7 +173,7 @@ static int strongarm_pic_initfn(SysBusDevice *dev)
     StrongARMPICState *s = FROM_SYSBUS(StrongARMPICState, dev);
 
     qdev_init_gpio_in(&dev->qdev, strongarm_pic_set_irq, SA_PIC_SRCS);
-    memory_region_init_io(&s->iomem, &strongarm_pic_ops, s, "pic", 0x1000);
+    memory_region_init_io(&s->iomem, NULL, &strongarm_pic_ops, s, "pic", 0x1000);
     sysbus_init_mmio(dev, &s->iomem);
     sysbus_init_irq(dev, &s->irq);
     sysbus_init_irq(dev, &s->fiq);
@@ -383,7 +383,7 @@ static int strongarm_rtc_init(SysBusDevice *dev)
     sysbus_init_irq(dev, &s->rtc_irq);
     sysbus_init_irq(dev, &s->rtc_hz_irq);
 
-    memory_region_init_io(&s->iomem, &strongarm_rtc_ops, s, "rtc", 0x10000);
+    memory_region_init_io(&s->iomem, NULL, &strongarm_rtc_ops, s, "rtc", 0x10000);
     sysbus_init_mmio(dev, &s->iomem);
 
     return 0;
@@ -637,7 +637,7 @@ static int strongarm_gpio_initfn(SysBusDevice *dev)
     qdev_init_gpio_in(&dev->qdev, strongarm_gpio_set, 28);
     qdev_init_gpio_out(&dev->qdev, s->handler, 28);
 
-    memory_region_init_io(&s->iomem, &strongarm_gpio_ops, s, "gpio", 0x1000);
+    memory_region_init_io(&s->iomem, NULL, &strongarm_gpio_ops, s, "gpio", 0x1000);
 
     sysbus_init_mmio(dev, &s->iomem);
     for (i = 0; i < 11; i++) {
@@ -808,7 +808,7 @@ static int strongarm_ppc_init(SysBusDevice *dev)
     qdev_init_gpio_in(&dev->qdev, strongarm_ppc_set, 22);
     qdev_init_gpio_out(&dev->qdev, s->handler, 22);
 
-    memory_region_init_io(&s->iomem, &strongarm_ppc_ops, s, "ppc", 0x1000);
+    memory_region_init_io(&s->iomem, NULL, &strongarm_ppc_ops, s, "ppc", 0x1000);
 
     sysbus_init_mmio(dev, &s->iomem);
 
@@ -1204,7 +1204,7 @@ static int strongarm_uart_init(SysBusDevice *dev)
 {
     StrongARMUARTState *s = FROM_SYSBUS(StrongARMUARTState, dev);
 
-    memory_region_init_io(&s->iomem, &strongarm_uart_ops, s, "uart", 0x10000);
+    memory_region_init_io(&s->iomem, NULL, &strongarm_uart_ops, s, "uart", 0x10000);
     sysbus_init_mmio(dev, &s->iomem);
     sysbus_init_irq(dev, &s->irq);
 
@@ -1496,7 +1496,7 @@ static int strongarm_ssp_init(SysBusDevice *dev)
 
     sysbus_init_irq(dev, &s->irq);
 
-    memory_region_init_io(&s->iomem, &strongarm_ssp_ops, s, "ssp", 0x1000);
+    memory_region_init_io(&s->iomem, NULL, &strongarm_ssp_ops, s, "ssp", 0x1000);
     sysbus_init_mmio(dev, &s->iomem);
 
     s->bus = ssi_create_bus(&dev->qdev, "ssi");
@@ -1571,7 +1571,7 @@ StrongARMState *sa1110_init(MemoryRegion *sysmem,
         exit(1);
     }
 
-    memory_region_init_ram(&s->sdram, "strongarm.sdram", sdram_size);
+    memory_region_init_ram(&s->sdram, NULL, "strongarm.sdram", sdram_size);
     vmstate_register_ram_global(&s->sdram);
     memory_region_add_subregion(sysmem, SA_SDCS0, &s->sdram);
 
diff --git a/hw/arm/tosa.c b/hw/arm/tosa.c
index 47818a5..47d1f4f 100644
--- a/hw/arm/tosa.c
+++ b/hw/arm/tosa.c
@@ -222,7 +222,7 @@ static void tosa_init(QEMUMachineInitArgs *args)
 
     mpu = pxa255_init(address_space_mem, tosa_binfo.ram_size);
 
-    memory_region_init_ram(rom, "tosa.rom", TOSA_ROM);
+    memory_region_init_ram(rom, NULL, "tosa.rom", TOSA_ROM);
     vmstate_register_ram_global(rom);
     memory_region_set_readonly(rom, true);
     memory_region_add_subregion(address_space_mem, 0, rom);
diff --git a/hw/arm/versatilepb.c b/hw/arm/versatilepb.c
index 753757e..cc06165 100644
--- a/hw/arm/versatilepb.c
+++ b/hw/arm/versatilepb.c
@@ -154,7 +154,7 @@ static int vpb_sic_init(SysBusDevice *dev)
         sysbus_init_irq(dev, &s->parent[i]);
     }
     s->irq = 31;
-    memory_region_init_io(&s->iomem, &vpb_sic_ops, s, "vpb-sic", 0x1000);
+    memory_region_init_io(&s->iomem, NULL, &vpb_sic_ops, s, "vpb-sic", 0x1000);
     sysbus_init_mmio(dev, &s->iomem);
     return 0;
 }
@@ -193,7 +193,7 @@ static void versatile_init(QEMUMachineInitArgs *args, int board_id)
         fprintf(stderr, "Unable to find CPU definition\n");
         exit(1);
     }
-    memory_region_init_ram(ram, "versatile.ram", args->ram_size);
+    memory_region_init_ram(ram, NULL, "versatile.ram", args->ram_size);
     vmstate_register_ram_global(ram);
     /* ??? RAM should repeat to fill physical memory space.  */
     /* SDRAM at address zero.  */
diff --git a/hw/arm/vexpress.c b/hw/arm/vexpress.c
index a077c62..710413e 100644
--- a/hw/arm/vexpress.c
+++ b/hw/arm/vexpress.c
@@ -196,7 +196,7 @@ static void a9_daughterboard_init(const VEDBoardInfo *daughterboard,
         exit(1);
     }
 
-    memory_region_init_ram(ram, "vexpress.highmem", ram_size);
+    memory_region_init_ram(ram, NULL, "vexpress.highmem", ram_size);
     vmstate_register_ram_global(ram);
     low_ram_size = ram_size;
     if (low_ram_size > 0x4000000) {
@@ -206,7 +206,7 @@ static void a9_daughterboard_init(const VEDBoardInfo *daughterboard,
      * address space should in theory be remappable to various
      * things including ROM or RAM; we always map the RAM there.
      */
-    memory_region_init_alias(lowram, "vexpress.lowmem", ram, 0, low_ram_size);
+    memory_region_init_alias(lowram, NULL, "vexpress.lowmem", ram, 0, low_ram_size);
     memory_region_add_subregion(sysmem, 0x0, lowram);
     memory_region_add_subregion(sysmem, 0x60000000, ram);
 
@@ -323,7 +323,7 @@ static void a15_daughterboard_init(const VEDBoardInfo *daughterboard,
         }
     }
 
-    memory_region_init_ram(ram, "vexpress.highmem", ram_size);
+    memory_region_init_ram(ram, NULL, "vexpress.highmem", ram_size);
     vmstate_register_ram_global(ram);
     /* RAM is from 0x80000000 upwards; there is no low-memory alias for it. */
     memory_region_add_subregion(sysmem, 0x80000000, ram);
@@ -357,7 +357,7 @@ static void a15_daughterboard_init(const VEDBoardInfo *daughterboard,
     /* 0x2b060000: SP805 watchdog: not modelled */
     /* 0x2b0a0000: PL341 dynamic memory controller: not modelled */
     /* 0x2e000000: system SRAM */
-    memory_region_init_ram(sram, "vexpress.a15sram", 0x10000);
+    memory_region_init_ram(sram, NULL, "vexpress.a15sram", 0x10000);
     vmstate_register_ram_global(sram);
     memory_region_add_subregion(sysmem, 0x2e000000, sram);
 
@@ -491,12 +491,12 @@ static void vexpress_common_init(const VEDBoardInfo *daughterboard,
     }
 
     sram_size = 0x2000000;
-    memory_region_init_ram(sram, "vexpress.sram", sram_size);
+    memory_region_init_ram(sram, NULL, "vexpress.sram", sram_size);
     vmstate_register_ram_global(sram);
     memory_region_add_subregion(sysmem, map[VE_SRAM], sram);
 
     vram_size = 0x800000;
-    memory_region_init_ram(vram, "vexpress.vram", vram_size);
+    memory_region_init_ram(vram, NULL, "vexpress.vram", vram_size);
     vmstate_register_ram_global(vram);
     memory_region_add_subregion(sysmem, map[VE_VIDEORAM], vram);
 
diff --git a/hw/arm/xilinx_zynq.c b/hw/arm/xilinx_zynq.c
index 4602a6f..0dc0871 100644
--- a/hw/arm/xilinx_zynq.c
+++ b/hw/arm/xilinx_zynq.c
@@ -132,12 +132,12 @@ static void zynq_init(QEMUMachineInitArgs *args)
     }
 
     /* DDR remapped to address zero.  */
-    memory_region_init_ram(ext_ram, "zynq.ext_ram", ram_size);
+    memory_region_init_ram(ext_ram, NULL, "zynq.ext_ram", ram_size);
     vmstate_register_ram_global(ext_ram);
     memory_region_add_subregion(address_space_mem, 0, ext_ram);
 
     /* 256K of on-chip memory */
-    memory_region_init_ram(ocm_ram, "zynq.ocm_ram", 256 << 10);
+    memory_region_init_ram(ocm_ram, NULL, "zynq.ocm_ram", 256 << 10);
     vmstate_register_ram_global(ocm_ram);
     memory_region_add_subregion(address_space_mem, 0xFFFC0000, ocm_ram);
 
diff --git a/hw/audio/ac97.c b/hw/audio/ac97.c
index baf138b..47e6f19 100644
--- a/hw/audio/ac97.c
+++ b/hw/audio/ac97.c
@@ -1378,8 +1378,8 @@ static int ac97_initfn (PCIDevice *dev)
     c[PCI_INTERRUPT_LINE] = 0x00;      /* intr_ln interrupt line rw */
     c[PCI_INTERRUPT_PIN] = 0x01;      /* intr_pn interrupt pin ro */
 
-    memory_region_init_io (&s->io_nam, &ac97_io_nam_ops, s, "ac97-nam", 1024);
-    memory_region_init_io (&s->io_nabm, &ac97_io_nabm_ops, s, "ac97-nabm", 256);
+    memory_region_init_io (&s->io_nam, NULL, &ac97_io_nam_ops, s, "ac97-nam", 1024);
+    memory_region_init_io (&s->io_nabm, NULL, &ac97_io_nabm_ops, s, "ac97-nabm", 256);
     pci_register_bar (&s->dev, 0, PCI_BASE_ADDRESS_SPACE_IO, &s->io_nam);
     pci_register_bar (&s->dev, 1, PCI_BASE_ADDRESS_SPACE_IO, &s->io_nabm);
     qemu_register_reset (ac97_on_reset, s);
diff --git a/hw/audio/cs4231.c b/hw/audio/cs4231.c
index 2975336..fb9b700 100644
--- a/hw/audio/cs4231.c
+++ b/hw/audio/cs4231.c
@@ -144,7 +144,7 @@ static int cs4231_init1(SysBusDevice *dev)
 {
     CSState *s = FROM_SYSBUS(CSState, dev);
 
-    memory_region_init_io(&s->iomem, &cs_mem_ops, s, "cs4321", CS_SIZE);
+    memory_region_init_io(&s->iomem, NULL, &cs_mem_ops, s, "cs4321", CS_SIZE);
     sysbus_init_mmio(dev, &s->iomem);
     sysbus_init_irq(dev, &s->irq);
 
diff --git a/hw/audio/cs4231a.c b/hw/audio/cs4231a.c
index 605dad4..c31da2e 100644
--- a/hw/audio/cs4231a.c
+++ b/hw/audio/cs4231a.c
@@ -648,7 +648,7 @@ static void cs4231a_initfn (Object *obj)
 {
     CSState *s = CS4231A (obj);
 
-    memory_region_init_io (&s->ioports, &cs_ioport_ops, s, "cs4231a", 4);
+    memory_region_init_io (&s->ioports, NULL, &cs_ioport_ops, s, "cs4231a", 4);
 }
 
 static void cs4231a_realizefn (DeviceState *dev, Error **errp)
diff --git a/hw/audio/es1370.c b/hw/audio/es1370.c
index c1cd169..b953df2 100644
--- a/hw/audio/es1370.c
+++ b/hw/audio/es1370.c
@@ -1035,7 +1035,7 @@ static int es1370_initfn (PCIDevice *dev)
     c[PCI_MIN_GNT] = 0x0c;
     c[PCI_MAX_LAT] = 0x80;
 
-    memory_region_init_io (&s->io, &es1370_io_ops, s, "es1370", 256);
+    memory_region_init_io (&s->io, NULL, &es1370_io_ops, s, "es1370", 256);
     pci_register_bar (&s->dev, 0, PCI_BASE_ADDRESS_SPACE_IO, &s->io);
     qemu_register_reset (es1370_on_reset, s);
 
diff --git a/hw/audio/intel-hda.c b/hw/audio/intel-hda.c
index 3ac90d5..e94602f 100644
--- a/hw/audio/intel-hda.c
+++ b/hw/audio/intel-hda.c
@@ -1135,7 +1135,7 @@ static int intel_hda_init(PCIDevice *pci)
     /* HDCTL off 0x40 bit 0 selects signaling mode (1-HDA, 0 - Ac97) 18.1.19 */
     conf[0x40] = 0x01;
 
-    memory_region_init_io(&d->mmio, &intel_hda_mmio_ops, d,
+    memory_region_init_io(&d->mmio, NULL, &intel_hda_mmio_ops, d,
                           "intel-hda", 0x4000);
     pci_register_bar(&d->pci, 0, 0, &d->mmio);
     if (d->msi) {
diff --git a/hw/audio/marvell_88w8618.c b/hw/audio/marvell_88w8618.c
index c5d88a7..e04e932 100644
--- a/hw/audio/marvell_88w8618.c
+++ b/hw/audio/marvell_88w8618.c
@@ -244,7 +244,7 @@ static int mv88w8618_audio_init(SysBusDevice *dev)
 
     wm8750_data_req_set(s->wm, mv88w8618_audio_callback, s);
 
-    memory_region_init_io(&s->iomem, &mv88w8618_audio_ops, s,
+    memory_region_init_io(&s->iomem, NULL, &mv88w8618_audio_ops, s,
                           "audio", MP_AUDIO_SIZE);
     sysbus_init_mmio(dev, &s->iomem);
 
diff --git a/hw/audio/milkymist-ac97.c b/hw/audio/milkymist-ac97.c
index e08e9dc..79a00fd 100644
--- a/hw/audio/milkymist-ac97.c
+++ b/hw/audio/milkymist-ac97.c
@@ -300,7 +300,7 @@ static int milkymist_ac97_init(SysBusDevice *dev)
     s->voice_out = AUD_open_out(&s->card, s->voice_out,
             "mm_ac97.out", s, ac97_out_cb, &as);
 
-    memory_region_init_io(&s->regs_region, &ac97_mmio_ops, s,
+    memory_region_init_io(&s->regs_region, NULL, &ac97_mmio_ops, s,
             "milkymist-ac97", R_MAX * 4);
     sysbus_init_mmio(dev, &s->regs_region);
 
diff --git a/hw/audio/pcspk.c b/hw/audio/pcspk.c
index 5dde0e7..123793b 100644
--- a/hw/audio/pcspk.c
+++ b/hw/audio/pcspk.c
@@ -167,7 +167,7 @@ static void pcspk_initfn(Object *obj)
 {
     PCSpkState *s = PC_SPEAKER(obj);
 
-    memory_region_init_io(&s->ioport, &pcspk_io_ops, s, "elcr", 1);
+    memory_region_init_io(&s->ioport, NULL, &pcspk_io_ops, s, "elcr", 1);
 }
 
 static void pcspk_realizefn(DeviceState *dev, Error **errp)
diff --git a/hw/audio/pl041.c b/hw/audio/pl041.c
index 653ab4f..5dd18c7 100644
--- a/hw/audio/pl041.c
+++ b/hw/audio/pl041.c
@@ -543,7 +543,7 @@ static int pl041_init(SysBusDevice *dev)
     }
 
     /* Connect the device to the sysbus */
-    memory_region_init_io(&s->iomem, &pl041_ops, s, "pl041", 0x1000);
+    memory_region_init_io(&s->iomem, NULL, &pl041_ops, s, "pl041", 0x1000);
     sysbus_init_mmio(dev, &s->iomem);
     sysbus_init_irq(dev, &s->irq);
 
diff --git a/hw/block/fdc.c b/hw/block/fdc.c
index 930f191..1bec805 100644
--- a/hw/block/fdc.c
+++ b/hw/block/fdc.c
@@ -2149,7 +2149,7 @@ static int sysbus_fdc_init1(SysBusDevice *dev)
     FDCtrl *fdctrl = &sys->state;
     int ret;
 
-    memory_region_init_io(&fdctrl->iomem, &fdctrl_mem_ops, fdctrl, "fdc", 0x08);
+    memory_region_init_io(&fdctrl->iomem, NULL, &fdctrl_mem_ops, fdctrl, "fdc", 0x08);
     sysbus_init_mmio(dev, &fdctrl->iomem);
     sysbus_init_irq(dev, &fdctrl->irq);
     qdev_init_gpio_in(&dev->qdev, fdctrl_handle_tc, 1);
@@ -2165,7 +2165,7 @@ static int sun4m_fdc_init1(SysBusDevice *dev)
 {
     FDCtrl *fdctrl = &(FROM_SYSBUS(FDCtrlSysBus, dev)->state);
 
-    memory_region_init_io(&fdctrl->iomem, &fdctrl_mem_strict_ops, fdctrl,
+    memory_region_init_io(&fdctrl->iomem, NULL, &fdctrl_mem_strict_ops, fdctrl,
                           "fdctrl", 0x08);
     sysbus_init_mmio(dev, &fdctrl->iomem);
     sysbus_init_irq(dev, &fdctrl->irq);
diff --git a/hw/block/nvme.c b/hw/block/nvme.c
index 58b0d91..aa3d9a9 100644
--- a/hw/block/nvme.c
+++ b/hw/block/nvme.c
@@ -777,7 +777,7 @@ static int nvme_init(PCIDevice *pci_dev)
     n->sq = g_malloc0(sizeof(*n->sq)*n->num_queues);
     n->cq = g_malloc0(sizeof(*n->cq)*n->num_queues);
 
-    memory_region_init_io(&n->iomem, &nvme_mmio_ops, n, "nvme", n->reg_size);
+    memory_region_init_io(&n->iomem, NULL, &nvme_mmio_ops, n, "nvme", n->reg_size);
     pci_register_bar(&n->parent_obj, 0,
         PCI_BASE_ADDRESS_SPACE_MEMORY | PCI_BASE_ADDRESS_MEM_TYPE_64,
         &n->iomem);
diff --git a/hw/block/onenand.c b/hw/block/onenand.c
index 8b511a7..edbce3c 100644
--- a/hw/block/onenand.c
+++ b/hw/block/onenand.c
@@ -113,9 +113,9 @@ static void onenand_mem_setup(OneNANDState *s)
     /* XXX: We should use IO_MEM_ROMD but we broke it earlier...
      * Both 0x0000 ... 0x01ff and 0x8000 ... 0x800f can be used to
      * write boot commands.  Also take note of the BWPS bit.  */
-    memory_region_init(&s->container, "onenand", 0x10000 << s->shift);
+    memory_region_init(&s->container, NULL, "onenand", 0x10000 << s->shift);
     memory_region_add_subregion(&s->container, 0, &s->iomem);
-    memory_region_init_alias(&s->mapped_ram, "onenand-mapped-ram",
+    memory_region_init_alias(&s->mapped_ram, NULL, "onenand-mapped-ram",
                              &s->ram, 0x0200 << s->shift,
                              0xbe00 << s->shift);
     memory_region_add_subregion_overlap(&s->container,
@@ -768,7 +768,7 @@ static int onenand_initfn(SysBusDevice *dev)
     s->blockwp = g_malloc(s->blocks);
     s->density_mask = (s->id.dev & 0x08)
         ? (1 << (6 + ((s->id.dev >> 4) & 7))) : 0;
-    memory_region_init_io(&s->iomem, &onenand_ops, s, "onenand",
+    memory_region_init_io(&s->iomem, NULL, &onenand_ops, s, "onenand",
                           0x10000 << s->shift);
     if (!s->bdrv) {
         s->image = memset(g_malloc(size + (size >> 5)),
@@ -782,7 +782,7 @@ static int onenand_initfn(SysBusDevice *dev)
     }
     s->otp = memset(g_malloc((64 + 2) << PAGE_SHIFT),
                     0xff, (64 + 2) << PAGE_SHIFT);
-    memory_region_init_ram(&s->ram, "onenand.ram", 0xc000 << s->shift);
+    memory_region_init_ram(&s->ram, NULL, "onenand.ram", 0xc000 << s->shift);
     vmstate_register_ram_global(&s->ram);
     ram = memory_region_get_ram_ptr(&s->ram);
     s->boot[0] = ram + (0x0000 << s->shift);
diff --git a/hw/block/pc_sysfw.c b/hw/block/pc_sysfw.c
index 412d1b0..0669410 100644
--- a/hw/block/pc_sysfw.c
+++ b/hw/block/pc_sysfw.c
@@ -59,7 +59,7 @@ static void pc_isa_bios_init(MemoryRegion *rom_memory,
         isa_bios_size = 128 * 1024;
     }
     isa_bios = g_malloc(sizeof(*isa_bios));
-    memory_region_init_ram(isa_bios, "isa-bios", isa_bios_size);
+    memory_region_init_ram(isa_bios, NULL, "isa-bios", isa_bios_size);
     vmstate_register_ram_global(isa_bios);
     memory_region_add_subregion_overlap(rom_memory,
                                         0x100000 - isa_bios_size,
@@ -162,7 +162,7 @@ static void old_pc_system_rom_init(MemoryRegion *rom_memory, bool isapc_ram_fw)
         goto bios_error;
     }
     bios = g_malloc(sizeof(*bios));
-    memory_region_init_ram(bios, "pc.bios", bios_size);
+    memory_region_init_ram(bios, NULL, "pc.bios", bios_size);
     vmstate_register_ram_global(bios);
     if (!isapc_ram_fw) {
         memory_region_set_readonly(bios, true);
@@ -183,7 +183,7 @@ static void old_pc_system_rom_init(MemoryRegion *rom_memory, bool isapc_ram_fw)
         isa_bios_size = 128 * 1024;
     }
     isa_bios = g_malloc(sizeof(*isa_bios));
-    memory_region_init_alias(isa_bios, "isa-bios", bios,
+    memory_region_init_alias(isa_bios, NULL, "isa-bios", bios,
                              bios_size - isa_bios_size, isa_bios_size);
     memory_region_add_subregion_overlap(rom_memory,
                                         0x100000 - isa_bios_size,
diff --git a/hw/block/pflash_cfi01.c b/hw/block/pflash_cfi01.c
index 63d7c99..5d51e58 100644
--- a/hw/block/pflash_cfi01.c
+++ b/hw/block/pflash_cfi01.c
@@ -579,7 +579,8 @@ static int pflash_cfi01_init(SysBusDevice *dev)
 #endif
 
     memory_region_init_rom_device(
-        &pfl->mem, pfl->be ? &pflash_cfi01_ops_be : &pflash_cfi01_ops_le, pfl,
+        &pfl->mem, NULL,
+        pfl->be ? &pflash_cfi01_ops_be : &pflash_cfi01_ops_le, pfl,
         pfl->name, total_len);
     vmstate_register_ram(&pfl->mem, DEVICE(pfl));
     pfl->storage = memory_region_get_ram_ptr(&pfl->mem);
diff --git a/hw/block/pflash_cfi02.c b/hw/block/pflash_cfi02.c
index 5f25246..8c1d570 100644
--- a/hw/block/pflash_cfi02.c
+++ b/hw/block/pflash_cfi02.c
@@ -100,10 +100,10 @@ static void pflash_setup_mappings(pflash_t *pfl)
     unsigned i;
     hwaddr size = memory_region_size(&pfl->orig_mem);
 
-    memory_region_init(&pfl->mem, "pflash", pfl->mappings * size);
+    memory_region_init(&pfl->mem, NULL, "pflash", pfl->mappings * size);
     pfl->mem_mappings = g_new(MemoryRegion, pfl->mappings);
     for (i = 0; i < pfl->mappings; ++i) {
-        memory_region_init_alias(&pfl->mem_mappings[i], "pflash-alias",
+        memory_region_init_alias(&pfl->mem_mappings[i], NULL, "pflash-alias",
                                  &pfl->orig_mem, 0, size);
         memory_region_add_subregion(&pfl->mem, i * size, &pfl->mem_mappings[i]);
     }
@@ -600,7 +600,7 @@ static int pflash_cfi02_init(SysBusDevice *dev)
         return NULL;
 #endif
 
-    memory_region_init_rom_device(&pfl->orig_mem, pfl->be ?
+    memory_region_init_rom_device(&pfl->orig_mem, NULL, pfl->be ?
                                   &pflash_cfi02_ops_be : &pflash_cfi02_ops_le,
                                   pfl, pfl->name, chip_len);
     vmstate_register_ram(&pfl->orig_mem, DEVICE(pfl));
diff --git a/hw/char/cadence_uart.c b/hw/char/cadence_uart.c
index 205e125..36e8cd5 100644
--- a/hw/char/cadence_uart.c
+++ b/hw/char/cadence_uart.c
@@ -442,7 +442,7 @@ static int cadence_uart_init(SysBusDevice *dev)
 {
     UartState *s = FROM_SYSBUS(UartState, dev);
 
-    memory_region_init_io(&s->iomem, &uart_ops, s, "uart", 0x1000);
+    memory_region_init_io(&s->iomem, NULL, &uart_ops, s, "uart", 0x1000);
     sysbus_init_mmio(dev, &s->iomem);
     sysbus_init_irq(dev, &s->irq);
 
diff --git a/hw/char/debugcon.c b/hw/char/debugcon.c
index f254841..c62fead 100644
--- a/hw/char/debugcon.c
+++ b/hw/char/debugcon.c
@@ -103,7 +103,7 @@ static void debugcon_isa_realizefn(DeviceState *dev, Error **errp)
         error_propagate(errp, err);
         return;
     }
-    memory_region_init_io(&s->io, &debugcon_ops, s,
+    memory_region_init_io(&s->io, NULL, &debugcon_ops, s,
                           TYPE_ISA_DEBUGCON_DEVICE, 1);
     memory_region_add_subregion(isa_address_space_io(d),
                                 isa->iobase, &s->io);
diff --git a/hw/char/escc.c b/hw/char/escc.c
index c2cb07f..29ecbaa 100644
--- a/hw/char/escc.c
+++ b/hw/char/escc.c
@@ -886,7 +886,7 @@ static int escc_init1(SysBusDevice *dev)
     s->chn[0].otherchn = &s->chn[1];
     s->chn[1].otherchn = &s->chn[0];
 
-    memory_region_init_io(&s->mmio, &escc_mem_ops, s, "escc",
+    memory_region_init_io(&s->mmio, NULL, &escc_mem_ops, s, "escc",
                           ESCC_SIZE << s->it_shift);
     sysbus_init_mmio(dev, &s->mmio);
 
diff --git a/hw/char/etraxfs_ser.c b/hw/char/etraxfs_ser.c
index 11820f5..ffd9767 100644
--- a/hw/char/etraxfs_ser.c
+++ b/hw/char/etraxfs_ser.c
@@ -211,7 +211,7 @@ static int etraxfs_ser_init(SysBusDevice *dev)
     struct etrax_serial *s = FROM_SYSBUS(typeof (*s), dev);
 
     sysbus_init_irq(dev, &s->irq);
-    memory_region_init_io(&s->mmio, &ser_ops, s, "etraxfs-serial", R_MAX * 4);
+    memory_region_init_io(&s->mmio, NULL, &ser_ops, s, "etraxfs-serial", R_MAX * 4);
     sysbus_init_mmio(dev, &s->mmio);
 
     s->chr = qemu_char_get_next_serial();
diff --git a/hw/char/exynos4210_uart.c b/hw/char/exynos4210_uart.c
index 5751816..b879ba4 100644
--- a/hw/char/exynos4210_uart.c
+++ b/hw/char/exynos4210_uart.c
@@ -630,7 +630,7 @@ static int exynos4210_uart_init(SysBusDevice *dev)
     Exynos4210UartState *s = FROM_SYSBUS(Exynos4210UartState, dev);
 
     /* memory mapping */
-    memory_region_init_io(&s->iomem, &exynos4210_uart_ops, s, "exynos4210.uart",
+    memory_region_init_io(&s->iomem, NULL, &exynos4210_uart_ops, s, "exynos4210.uart",
                           EXYNOS4210_UART_REGS_MEM_SIZE);
     sysbus_init_mmio(dev, &s->iomem);
 
diff --git a/hw/char/grlib_apbuart.c b/hw/char/grlib_apbuart.c
index a64453f..a1587dc 100644
--- a/hw/char/grlib_apbuart.c
+++ b/hw/char/grlib_apbuart.c
@@ -242,7 +242,7 @@ static int grlib_apbuart_init(SysBusDevice *dev)
 
     sysbus_init_irq(dev, &uart->irq);
 
-    memory_region_init_io(&uart->iomem, &grlib_apbuart_ops, uart,
+    memory_region_init_io(&uart->iomem, NULL, &grlib_apbuart_ops, uart,
                           "uart", UART_REG_SIZE);
 
     sysbus_init_mmio(dev, &uart->iomem);
diff --git a/hw/char/imx_serial.c b/hw/char/imx_serial.c
index 2a2c230..9fa4da7 100644
--- a/hw/char/imx_serial.c
+++ b/hw/char/imx_serial.c
@@ -386,7 +386,7 @@ static int imx_serial_init(SysBusDevice *dev)
     IMXSerialState *s = FROM_SYSBUS(IMXSerialState, dev);
 
 
-    memory_region_init_io(&s->iomem, &imx_serial_ops, s, "imx-serial", 0x1000);
+    memory_region_init_io(&s->iomem, NULL, &imx_serial_ops, s, "imx-serial", 0x1000);
     sysbus_init_mmio(dev, &s->iomem);
     sysbus_init_irq(dev, &s->irq);
 
diff --git a/hw/char/lm32_uart.c b/hw/char/lm32_uart.c
index 99721ab..e8fdbe4 100644
--- a/hw/char/lm32_uart.c
+++ b/hw/char/lm32_uart.c
@@ -250,7 +250,7 @@ static int lm32_uart_init(SysBusDevice *dev)
 
     sysbus_init_irq(dev, &s->irq);
 
-    memory_region_init_io(&s->iomem, &uart_ops, s, "uart", R_MAX * 4);
+    memory_region_init_io(&s->iomem, NULL, &uart_ops, s, "uart", R_MAX * 4);
     sysbus_init_mmio(dev, &s->iomem);
 
     s->chr = qemu_char_get_next_serial();
diff --git a/hw/char/mcf_uart.c b/hw/char/mcf_uart.c
index 3ec4705..98fd44e 100644
--- a/hw/char/mcf_uart.c
+++ b/hw/char/mcf_uart.c
@@ -302,6 +302,6 @@ void mcf_uart_mm_init(MemoryRegion *sysmem,
     mcf_uart_state *s;
 
     s = mcf_uart_init(irq, chr);
-    memory_region_init_io(&s->iomem, &mcf_uart_ops, s, "uart", 0x40);
+    memory_region_init_io(&s->iomem, NULL, &mcf_uart_ops, s, "uart", 0x40);
     memory_region_add_subregion(sysmem, base, &s->iomem);
 }
diff --git a/hw/char/milkymist-uart.c b/hw/char/milkymist-uart.c
index cbc7d73..22faf4c 100644
--- a/hw/char/milkymist-uart.c
+++ b/hw/char/milkymist-uart.c
@@ -196,7 +196,7 @@ static int milkymist_uart_init(SysBusDevice *dev)
 
     sysbus_init_irq(dev, &s->irq);
 
-    memory_region_init_io(&s->regs_region, &uart_mmio_ops, s,
+    memory_region_init_io(&s->regs_region, NULL, &uart_mmio_ops, s,
             "milkymist-uart", R_MAX * 4);
     sysbus_init_mmio(dev, &s->regs_region);
 
diff --git a/hw/char/omap_uart.c b/hw/char/omap_uart.c
index 5bb36ed..0b91693 100644
--- a/hw/char/omap_uart.c
+++ b/hw/char/omap_uart.c
@@ -168,7 +168,7 @@ struct omap_uart_s *omap2_uart_init(MemoryRegion *sysmem,
     struct omap_uart_s *s = omap_uart_init(base, irq,
                     fclk, iclk, txdma, rxdma, label, chr);
 
-    memory_region_init_io(&s->iomem, &omap_uart_ops, s, "omap.uart", 0x100);
+    memory_region_init_io(&s->iomem, NULL, &omap_uart_ops, s, "omap.uart", 0x100);
 
     s->ta = ta;
 
diff --git a/hw/char/parallel.c b/hw/char/parallel.c
index caa9eb4..ad96ea5 100644
--- a/hw/char/parallel.c
+++ b/hw/char/parallel.c
@@ -587,7 +587,7 @@ bool parallel_mm_init(MemoryRegion *address_space,
     s->it_shift = it_shift;
     qemu_register_reset(parallel_reset, s);
 
-    memory_region_init_io(&s->iomem, &parallel_mm_ops, s,
+    memory_region_init_io(&s->iomem, NULL, &parallel_mm_ops, s,
                           "parallel", 8 << it_shift);
     memory_region_add_subregion(address_space, base, &s->iomem);
     return true;
diff --git a/hw/char/pl011.c b/hw/char/pl011.c
index 7079ef6..bd26e6d 100644
--- a/hw/char/pl011.c
+++ b/hw/char/pl011.c
@@ -265,7 +265,7 @@ static int pl011_init(SysBusDevice *dev, const unsigned char *id)
 {
     pl011_state *s = FROM_SYSBUS(pl011_state, dev);
 
-    memory_region_init_io(&s->iomem, &pl011_ops, s, "pl011", 0x1000);
+    memory_region_init_io(&s->iomem, NULL, &pl011_ops, s, "pl011", 0x1000);
     sysbus_init_mmio(dev, &s->iomem);
     sysbus_init_irq(dev, &s->irq);
     s->id = id;
diff --git a/hw/char/serial-isa.c b/hw/char/serial-isa.c
index e06a802..0bce75b 100644
--- a/hw/char/serial-isa.c
+++ b/hw/char/serial-isa.c
@@ -72,7 +72,7 @@ static void serial_isa_realizefn(DeviceState *dev, Error **errp)
     serial_realize_core(s, errp);
     qdev_set_legacy_instance_id(dev, isa->iobase, 3);
 
-    memory_region_init_io(&s->io, &serial_io_ops, s, "serial", 8);
+    memory_region_init_io(&s->io, NULL, &serial_io_ops, s, "serial", 8);
     isa_register_ioport(isadev, &s->io, isa->iobase);
 }
 
diff --git a/hw/char/serial-pci.c b/hw/char/serial-pci.c
index 3bec8eb..6adfbe6 100644
--- a/hw/char/serial-pci.c
+++ b/hw/char/serial-pci.c
@@ -63,7 +63,7 @@ static int serial_pci_init(PCIDevice *dev)
     pci->dev.config[PCI_INTERRUPT_PIN] = 0x01;
     s->irq = pci->dev.irq[0];
 
-    memory_region_init_io(&s->io, &serial_io_ops, s, "serial", 8);
+    memory_region_init_io(&s->io, NULL, &serial_io_ops, s, "serial", 8);
     pci_register_bar(&pci->dev, 0, PCI_BASE_ADDRESS_SPACE_IO, &s->io);
     return 0;
 }
@@ -102,7 +102,7 @@ static int multi_serial_pci_init(PCIDevice *dev)
     assert(pci->ports <= PCI_SERIAL_MAX_PORTS);
 
     pci->dev.config[PCI_INTERRUPT_PIN] = 0x01;
-    memory_region_init(&pci->iobar, "multiserial", 8 * pci->ports);
+    memory_region_init(&pci->iobar, NULL, "multiserial", 8 * pci->ports);
     pci_register_bar(&pci->dev, 0, PCI_BASE_ADDRESS_SPACE_IO, &pci->iobar);
     pci->irqs = qemu_allocate_irqs(multi_serial_irq_mux, pci,
                                    pci->ports);
@@ -118,7 +118,7 @@ static int multi_serial_pci_init(PCIDevice *dev)
         }
         s->irq = pci->irqs[i];
         pci->name[i] = g_strdup_printf("uart #%d", i+1);
-        memory_region_init_io(&s->io, &serial_io_ops, s, pci->name[i], 8);
+        memory_region_init_io(&s->io, NULL, &serial_io_ops, s, pci->name[i], 8);
         memory_region_add_subregion(&pci->iobar, 8 * i, &s->io);
     }
     return 0;
diff --git a/hw/char/serial.c b/hw/char/serial.c
index 6382f98..6025592 100644
--- a/hw/char/serial.c
+++ b/hw/char/serial.c
@@ -703,7 +703,7 @@ SerialState *serial_init(int base, qemu_irq irq, int baudbase,
 
     vmstate_register(NULL, base, &vmstate_serial, s);
 
-    memory_region_init_io(&s->io, &serial_io_ops, s, "serial", 8);
+    memory_region_init_io(&s->io, NULL, &serial_io_ops, s, "serial", 8);
     memory_region_add_subregion(system_io, base, &s->io);
 
     return s;
@@ -766,7 +766,7 @@ SerialState *serial_mm_init(MemoryRegion *address_space,
     }
     vmstate_register(NULL, base, &vmstate_serial, s);
 
-    memory_region_init_io(&s->io, &serial_mm_ops[end], s,
+    memory_region_init_io(&s->io, NULL, &serial_mm_ops[end], s,
                           "serial", 8 << it_shift);
     memory_region_add_subregion(address_space, base, &s->io);
 
diff --git a/hw/char/sh_serial.c b/hw/char/sh_serial.c
index b328643..6223a55 100644
--- a/hw/char/sh_serial.c
+++ b/hw/char/sh_serial.c
@@ -383,14 +383,14 @@ void sh_serial_init(MemoryRegion *sysmem,
 
     sh_serial_clear_fifo(s);
 
-    memory_region_init_io(&s->iomem, &sh_serial_ops, s,
+    memory_region_init_io(&s->iomem, NULL, &sh_serial_ops, s,
                           "serial", 0x100000000ULL);
 
-    memory_region_init_alias(&s->iomem_p4, "serial-p4", &s->iomem,
+    memory_region_init_alias(&s->iomem_p4, NULL, "serial-p4", &s->iomem,
                              0, 0x28);
     memory_region_add_subregion(sysmem, P4ADDR(base), &s->iomem_p4);
 
-    memory_region_init_alias(&s->iomem_a7, "serial-a7", &s->iomem,
+    memory_region_init_alias(&s->iomem_a7, NULL, "serial-a7", &s->iomem,
                              0, 0x28);
     memory_region_add_subregion(sysmem, A7ADDR(base), &s->iomem_a7);
 
diff --git a/hw/char/tpci200.c b/hw/char/tpci200.c
index 0170602..9174042 100644
--- a/hw/char/tpci200.c
+++ b/hw/char/tpci200.c
@@ -588,17 +588,17 @@ static int tpci200_initfn(PCIDevice *pci_dev)
     pci_set_long(c + 0x48, 0x00024C06);
     pci_set_long(c + 0x4C, 0x00000003);
 
-    memory_region_init_io(&s->mmio, &tpci200_cfg_ops,
+    memory_region_init_io(&s->mmio, NULL, &tpci200_cfg_ops,
                           s, "tpci200_mmio", 128);
-    memory_region_init_io(&s->io,   &tpci200_cfg_ops,
+    memory_region_init_io(&s->io, NULL,   &tpci200_cfg_ops,
                           s, "tpci200_io",   128);
-    memory_region_init_io(&s->las0, &tpci200_las0_ops,
+    memory_region_init_io(&s->las0, NULL, &tpci200_las0_ops,
                           s, "tpci200_las0", 256);
-    memory_region_init_io(&s->las1, &tpci200_las1_ops,
+    memory_region_init_io(&s->las1, NULL, &tpci200_las1_ops,
                           s, "tpci200_las1", 1024);
-    memory_region_init_io(&s->las2, &tpci200_las2_ops,
+    memory_region_init_io(&s->las2, NULL, &tpci200_las2_ops,
                           s, "tpci200_las2", 1024*1024*32);
-    memory_region_init_io(&s->las3, &tpci200_las3_ops,
+    memory_region_init_io(&s->las3, NULL, &tpci200_las3_ops,
                           s, "tpci200_las3", 1024*1024*16);
     pci_register_bar(&s->dev, 0, PCI_BASE_ADDRESS_SPACE_MEMORY, &s->mmio);
     pci_register_bar(&s->dev, 1, PCI_BASE_ADDRESS_SPACE_IO,     &s->io);
diff --git a/hw/char/xilinx_uartlite.c b/hw/char/xilinx_uartlite.c
index 3f7e989..241bf1f 100644
--- a/hw/char/xilinx_uartlite.c
+++ b/hw/char/xilinx_uartlite.c
@@ -199,7 +199,7 @@ static int xilinx_uartlite_init(SysBusDevice *dev)
     sysbus_init_irq(dev, &s->irq);
 
     uart_update_status(s);
-    memory_region_init_io(&s->mmio, &uart_ops, s, "xlnx.xps-uartlite",
+    memory_region_init_io(&s->mmio, NULL, &uart_ops, s, "xlnx.xps-uartlite",
                                                                 R_MAX * 4);
     sysbus_init_mmio(dev, &s->mmio);
 
diff --git a/hw/core/empty_slot.c b/hw/core/empty_slot.c
index 5234a4d..35e32f9 100644
--- a/hw/core/empty_slot.c
+++ b/hw/core/empty_slot.c
@@ -70,7 +70,7 @@ static int empty_slot_init1(SysBusDevice *dev)
 {
     EmptySlot *s = FROM_SYSBUS(EmptySlot, dev);
 
-    memory_region_init_io(&s->iomem, &empty_slot_ops, s,
+    memory_region_init_io(&s->iomem, NULL, &empty_slot_ops, s,
                           "empty-slot", s->size);
     sysbus_init_mmio(dev, &s->iomem);
     return 0;
diff --git a/hw/cpu/a15mpcore.c b/hw/cpu/a15mpcore.c
index 648656d..773c83a 100644
--- a/hw/cpu/a15mpcore.c
+++ b/hw/cpu/a15mpcore.c
@@ -68,7 +68,7 @@ static int a15mp_priv_init(SysBusDevice *dev)
      *  0x5000-0x5fff -- GIC virtual interface control (not modelled)
      *  0x6000-0x7fff -- GIC virtual CPU interface (not modelled)
      */
-    memory_region_init(&s->container, "a15mp-priv-container", 0x8000);
+    memory_region_init(&s->container, NULL, "a15mp-priv-container", 0x8000);
     memory_region_add_subregion(&s->container, 0x1000,
                                 sysbus_mmio_get_region(busdev, 0));
     memory_region_add_subregion(&s->container, 0x2000,
diff --git a/hw/cpu/a9mpcore.c b/hw/cpu/a9mpcore.c
index 0a1a10f..26a3858 100644
--- a/hw/cpu/a9mpcore.c
+++ b/hw/cpu/a9mpcore.c
@@ -71,7 +71,7 @@ static int a9mp_priv_init(SysBusDevice *dev)
      *
      * We should implement the global timer but don't currently do so.
      */
-    memory_region_init(&s->container, "a9mp-priv-container", 0x2000);
+    memory_region_init(&s->container, NULL, "a9mp-priv-container", 0x2000);
     memory_region_add_subregion(&s->container, 0,
                                 sysbus_mmio_get_region(scubusdev, 0));
     /* GIC CPU interface */
diff --git a/hw/cpu/arm11mpcore.c b/hw/cpu/arm11mpcore.c
index 90dcead..67e2828 100644
--- a/hw/cpu/arm11mpcore.c
+++ b/hw/cpu/arm11mpcore.c
@@ -87,8 +87,8 @@ static void mpcore_priv_map_setup(ARM11MPCorePriveState *s)
     SysBusDevice *gicbusdev = SYS_BUS_DEVICE(s->gic);
     SysBusDevice *timerbusdev = SYS_BUS_DEVICE(s->mptimer);
     SysBusDevice *wdtbusdev = SYS_BUS_DEVICE(s->wdtimer);
-    memory_region_init(&s->container, "mpcode-priv-container", 0x2000);
-    memory_region_init_io(&s->iomem, &mpcore_scu_ops, s, "mpcore-scu", 0x100);
+    memory_region_init(&s->container, NULL, "mpcode-priv-container", 0x2000);
+    memory_region_init_io(&s->iomem, NULL, &mpcore_scu_ops, s, "mpcore-scu", 0x100);
     memory_region_add_subregion(&s->container, 0, &s->iomem);
     /* GIC CPU interfaces: "current CPU" at 0x100, then specific CPUs
      * at 0x200, 0x300...
diff --git a/hw/cpu/icc_bus.c b/hw/cpu/icc_bus.c
index 73a1dc9..9e901e9 100644
--- a/hw/cpu/icc_bus.c
+++ b/hw/cpu/icc_bus.c
@@ -95,7 +95,7 @@ static void icc_bridge_init(Object *obj)
     /* Do not change order of registering regions,
      * APIC must be first registered region, board maps it by 0 index
      */
-    memory_region_init(&s->apic_container, "icc-apic-container",
+    memory_region_init(&s->apic_container, NULL, "icc-apic-container",
                        APIC_SPACE_SIZE);
     sysbus_init_mmio(sb, &s->apic_container);
     s->icc_bus.apic_address_space = &s->apic_container;
diff --git a/hw/cris/axis_dev88.c b/hw/cris/axis_dev88.c
index 7475671..9104d61 100644
--- a/hw/cris/axis_dev88.c
+++ b/hw/cris/axis_dev88.c
@@ -269,13 +269,13 @@ void axisdev88_init(QEMUMachineInitArgs *args)
     env = &cpu->env;
 
     /* allocate RAM */
-    memory_region_init_ram(phys_ram, "axisdev88.ram", ram_size);
+    memory_region_init_ram(phys_ram, NULL, "axisdev88.ram", ram_size);
     vmstate_register_ram_global(phys_ram);
     memory_region_add_subregion(address_space_mem, 0x40000000, phys_ram);
 
     /* The ETRAX-FS has 128Kb on chip ram, the docs refer to it as the 
        internal memory.  */
-    memory_region_init_ram(phys_intmem, "axisdev88.chipram", INTMEM_SIZE);
+    memory_region_init_ram(phys_intmem, NULL, "axisdev88.chipram", INTMEM_SIZE);
     vmstate_register_ram_global(phys_intmem);
     memory_region_add_subregion(address_space_mem, 0x38000000, phys_intmem);
 
@@ -283,13 +283,13 @@ void axisdev88_init(QEMUMachineInitArgs *args)
     nand = drive_get(IF_MTD, 0, 0);
     nand_state.nand = nand_init(nand ? nand->bdrv : NULL,
                                 NAND_MFR_STMICRO, 0x39);
-    memory_region_init_io(&nand_state.iomem, &nand_ops, &nand_state,
+    memory_region_init_io(&nand_state.iomem, NULL, &nand_ops, &nand_state,
                           "nand", 0x05000000);
     memory_region_add_subregion(address_space_mem, 0x10000000,
                                 &nand_state.iomem);
 
     gpio_state.nand = &nand_state;
-    memory_region_init_io(&gpio_state.iomem, &gpio_ops, &gpio_state,
+    memory_region_init_io(&gpio_state.iomem, NULL, &gpio_ops, &gpio_state,
                           "gpio", 0x5c);
     memory_region_add_subregion(address_space_mem, 0x3001a000,
                                 &gpio_state.iomem);
diff --git a/hw/display/cirrus_vga.c b/hw/display/cirrus_vga.c
index 0d9eee8..00ac9a3 100644
--- a/hw/display/cirrus_vga.c
+++ b/hw/display/cirrus_vga.c
@@ -2840,21 +2840,21 @@ static void cirrus_init_common(CirrusVGAState * s, int device_id, int is_pci,
     }
 
     /* Register ioport 0x3b0 - 0x3df */
-    memory_region_init_io(&s->cirrus_vga_io, &cirrus_vga_io_ops, s,
+    memory_region_init_io(&s->cirrus_vga_io, NULL, &cirrus_vga_io_ops, s,
                           "cirrus-io", 0x30);
     memory_region_add_subregion(system_io, 0x3b0, &s->cirrus_vga_io);
 
-    memory_region_init(&s->low_mem_container,
+    memory_region_init(&s->low_mem_container, NULL,
                        "cirrus-lowmem-container",
                        0x20000);
 
-    memory_region_init_io(&s->low_mem, &cirrus_vga_mem_ops, s,
+    memory_region_init_io(&s->low_mem, NULL, &cirrus_vga_mem_ops, s,
                           "cirrus-low-memory", 0x20000);
     memory_region_add_subregion(&s->low_mem_container, 0, &s->low_mem);
     for (i = 0; i < 2; ++i) {
         static const char *names[] = { "vga.bank0", "vga.bank1" };
         MemoryRegion *bank = &s->cirrus_bank[i];
-        memory_region_init_alias(bank, names[i], &s->vga.vram, 0, 0x8000);
+        memory_region_init_alias(bank, NULL, names[i], &s->vga.vram, 0, 0x8000);
         memory_region_set_enabled(bank, false);
         memory_region_add_subregion_overlap(&s->low_mem_container, i * 0x8000,
                                             bank, 1);
@@ -2866,13 +2866,13 @@ static void cirrus_init_common(CirrusVGAState * s, int device_id, int is_pci,
     memory_region_set_coalescing(&s->low_mem);
 
     /* I/O handler for LFB */
-    memory_region_init_io(&s->cirrus_linear_io, &cirrus_linear_io_ops, s,
+    memory_region_init_io(&s->cirrus_linear_io, NULL, &cirrus_linear_io_ops, s,
                           "cirrus-linear-io", s->vga.vram_size_mb
                                               * 1024 * 1024);
     memory_region_set_flush_coalesced(&s->cirrus_linear_io);
 
     /* I/O handler for LFB */
-    memory_region_init_io(&s->cirrus_linear_bitblt_io,
+    memory_region_init_io(&s->cirrus_linear_bitblt_io, NULL,
                           &cirrus_linear_bitblt_io_ops,
                           s,
                           "cirrus-bitblt-mmio",
@@ -2880,7 +2880,7 @@ static void cirrus_init_common(CirrusVGAState * s, int device_id, int is_pci,
     memory_region_set_flush_coalesced(&s->cirrus_linear_bitblt_io);
 
     /* I/O handler for memory-mapped I/O */
-    memory_region_init_io(&s->cirrus_mmio_io, &cirrus_mmio_io_ops, s,
+    memory_region_init_io(&s->cirrus_mmio_io, NULL, &cirrus_mmio_io_ops, s,
                           "cirrus-mmio", CIRRUS_PNPMMIO_SIZE);
     memory_region_set_flush_coalesced(&s->cirrus_mmio_io);
 
@@ -2965,7 +2965,7 @@ static int pci_cirrus_vga_initfn(PCIDevice *dev)
 
      /* setup PCI */
 
-    memory_region_init(&s->pci_bar, "cirrus-pci-bar0", 0x2000000);
+    memory_region_init(&s->pci_bar, NULL, "cirrus-pci-bar0", 0x2000000);
 
     /* XXX: add byte swapping apertures */
     memory_region_add_subregion(&s->pci_bar, 0, &s->cirrus_linear_io);
diff --git a/hw/display/exynos4210_fimd.c b/hw/display/exynos4210_fimd.c
index 0da00a9..d9088d9 100644
--- a/hw/display/exynos4210_fimd.c
+++ b/hw/display/exynos4210_fimd.c
@@ -1902,7 +1902,7 @@ static int exynos4210_fimd_init(SysBusDevice *dev)
     sysbus_init_irq(dev, &s->irq[1]);
     sysbus_init_irq(dev, &s->irq[2]);
 
-    memory_region_init_io(&s->iomem, &exynos4210_fimd_mmio_ops, s,
+    memory_region_init_io(&s->iomem, NULL, &exynos4210_fimd_mmio_ops, s,
             "exynos4210.fimd", FIMD_REGS_SIZE);
     sysbus_init_mmio(dev, &s->iomem);
     s->console = graphic_console_init(DEVICE(dev), &exynos4210_fimd_ops, s);
diff --git a/hw/display/g364fb.c b/hw/display/g364fb.c
index 2a4047e..79a0a50 100644
--- a/hw/display/g364fb.c
+++ b/hw/display/g364fb.c
@@ -486,8 +486,8 @@ static void g364fb_init(DeviceState *dev, G364State *s)
 
     s->con = graphic_console_init(dev, &g364fb_ops, s);
 
-    memory_region_init_io(&s->mem_ctrl, &g364fb_ctrl_ops, s, "ctrl", 0x180000);
-    memory_region_init_ram_ptr(&s->mem_vram, "vram",
+    memory_region_init_io(&s->mem_ctrl, NULL, &g364fb_ctrl_ops, s, "ctrl", 0x180000);
+    memory_region_init_ram_ptr(&s->mem_vram, NULL, "vram",
                                s->vram_size, s->vram);
     vmstate_register_ram(&s->mem_vram, dev);
     memory_region_set_coalescing(&s->mem_vram);
diff --git a/hw/display/jazz_led.c b/hw/display/jazz_led.c
index 52035fc..e6a508e 100644
--- a/hw/display/jazz_led.c
+++ b/hw/display/jazz_led.c
@@ -264,7 +264,7 @@ static int jazz_led_init(SysBusDevice *dev)
 {
     LedState *s = FROM_SYSBUS(LedState, dev);
 
-    memory_region_init_io(&s->iomem, &led_ops, s, "led", 1);
+    memory_region_init_io(&s->iomem, NULL, &led_ops, s, "led", 1);
     sysbus_init_mmio(dev, &s->iomem);
 
     s->con = graphic_console_init(DEVICE(dev), &jazz_led_ops, s);
diff --git a/hw/display/milkymist-tmu2.c b/hw/display/milkymist-tmu2.c
index b723a04..31da796 100644
--- a/hw/display/milkymist-tmu2.c
+++ b/hw/display/milkymist-tmu2.c
@@ -447,7 +447,7 @@ static int milkymist_tmu2_init(SysBusDevice *dev)
 
     sysbus_init_irq(dev, &s->irq);
 
-    memory_region_init_io(&s->regs_region, &tmu2_mmio_ops, s,
+    memory_region_init_io(&s->regs_region, NULL, &tmu2_mmio_ops, s,
             "milkymist-tmu2", R_MAX * 4);
     sysbus_init_mmio(dev, &s->regs_region);
 
diff --git a/hw/display/milkymist-vgafb.c b/hw/display/milkymist-vgafb.c
index 3828296..b1f9c16 100644
--- a/hw/display/milkymist-vgafb.c
+++ b/hw/display/milkymist-vgafb.c
@@ -279,7 +279,7 @@ static int milkymist_vgafb_init(SysBusDevice *dev)
 {
     MilkymistVgafbState *s = FROM_SYSBUS(typeof(*s), dev);
 
-    memory_region_init_io(&s->regs_region, &vgafb_mmio_ops, s,
+    memory_region_init_io(&s->regs_region, NULL, &vgafb_mmio_ops, s,
             "milkymist-vgafb", R_MAX * 4);
     sysbus_init_mmio(dev, &s->regs_region);
 
diff --git a/hw/display/omap_dss.c b/hw/display/omap_dss.c
index ea3afce..24ccbcc 100644
--- a/hw/display/omap_dss.c
+++ b/hw/display/omap_dss.c
@@ -1053,15 +1053,15 @@ struct omap_dss_s *omap_dss_init(struct omap_target_agent_s *ta,
     s->drq = drq;
     omap_dss_reset(s);
 
-    memory_region_init_io(&s->iomem_diss1, &omap_diss_ops, s, "omap.diss1",
+    memory_region_init_io(&s->iomem_diss1, NULL, &omap_diss_ops, s, "omap.diss1",
                           omap_l4_region_size(ta, 0));
-    memory_region_init_io(&s->iomem_disc1, &omap_disc_ops, s, "omap.disc1",
+    memory_region_init_io(&s->iomem_disc1, NULL, &omap_disc_ops, s, "omap.disc1",
                           omap_l4_region_size(ta, 1));
-    memory_region_init_io(&s->iomem_rfbi1, &omap_rfbi_ops, s, "omap.rfbi1",
+    memory_region_init_io(&s->iomem_rfbi1, NULL, &omap_rfbi_ops, s, "omap.rfbi1",
                           omap_l4_region_size(ta, 2));
-    memory_region_init_io(&s->iomem_venc1, &omap_venc_ops, s, "omap.venc1",
+    memory_region_init_io(&s->iomem_venc1, NULL, &omap_venc_ops, s, "omap.venc1",
                           omap_l4_region_size(ta, 3));
-    memory_region_init_io(&s->iomem_im3, &omap_im3_ops, s,
+    memory_region_init_io(&s->iomem_im3, NULL, &omap_im3_ops, s,
                           "omap.im3", 0x1000);
 
     omap_l4_attach(ta, 0, &s->iomem_diss1);
diff --git a/hw/display/omap_lcdc.c b/hw/display/omap_lcdc.c
index fb72ebe..c3b9b68 100644
--- a/hw/display/omap_lcdc.c
+++ b/hw/display/omap_lcdc.c
@@ -403,7 +403,7 @@ struct omap_lcd_panel_s *omap_lcdc_init(MemoryRegion *sysmem,
     s->sysmem = sysmem;
     omap_lcdc_reset(s);
 
-    memory_region_init_io(&s->iomem, &omap_lcdc_ops, s, "omap.lcdc", 0x100);
+    memory_region_init_io(&s->iomem, NULL, &omap_lcdc_ops, s, "omap.lcdc", 0x100);
     memory_region_add_subregion(sysmem, base, &s->iomem);
 
     s->con = graphic_console_init(NULL, &omap_ops, s);
diff --git a/hw/display/pl110.c b/hw/display/pl110.c
index f259955..15c2f38 100644
--- a/hw/display/pl110.c
+++ b/hw/display/pl110.c
@@ -453,7 +453,7 @@ static int pl110_init(SysBusDevice *dev)
 {
     pl110_state *s = FROM_SYSBUS(pl110_state, dev);
 
-    memory_region_init_io(&s->iomem, &pl110_ops, s, "pl110", 0x1000);
+    memory_region_init_io(&s->iomem, NULL, &pl110_ops, s, "pl110", 0x1000);
     sysbus_init_mmio(dev, &s->iomem);
     sysbus_init_irq(dev, &s->irq);
     qdev_init_gpio_in(&s->busdev.qdev, pl110_mux_ctrl_set, 1);
diff --git a/hw/display/pxa2xx_lcd.c b/hw/display/pxa2xx_lcd.c
index 3b68f26..990931a 100644
--- a/hw/display/pxa2xx_lcd.c
+++ b/hw/display/pxa2xx_lcd.c
@@ -1009,7 +1009,7 @@ PXA2xxLCDState *pxa2xx_lcdc_init(MemoryRegion *sysmem,
 
     pxa2xx_lcdc_orientation(s, graphic_rotate);
 
-    memory_region_init_io(&s->iomem, &pxa2xx_lcdc_ops, s,
+    memory_region_init_io(&s->iomem, NULL, &pxa2xx_lcdc_ops, s,
                           "pxa2xx-lcd-controller", 0x00100000);
     memory_region_add_subregion(sysmem, base, &s->iomem);
 
diff --git a/hw/display/qxl.c b/hw/display/qxl.c
index 937a402..bcfcce4 100644
--- a/hw/display/qxl.c
+++ b/hw/display/qxl.c
@@ -1981,18 +1981,18 @@ static int qxl_init_common(PCIQXLDevice *qxl)
     pci_set_byte(&config[PCI_INTERRUPT_PIN], 1);
 
     qxl->rom_size = qxl_rom_size();
-    memory_region_init_ram(&qxl->rom_bar, "qxl.vrom", qxl->rom_size);
+    memory_region_init_ram(&qxl->rom_bar, NULL, "qxl.vrom", qxl->rom_size);
     vmstate_register_ram(&qxl->rom_bar, &qxl->pci.qdev);
     init_qxl_rom(qxl);
     init_qxl_ram(qxl);
 
     qxl->guest_surfaces.cmds = g_new0(QXLPHYSICAL, qxl->ssd.num_surfaces);
-    memory_region_init_ram(&qxl->vram_bar, "qxl.vram", qxl->vram_size);
+    memory_region_init_ram(&qxl->vram_bar, NULL, "qxl.vram", qxl->vram_size);
     vmstate_register_ram(&qxl->vram_bar, &qxl->pci.qdev);
-    memory_region_init_alias(&qxl->vram32_bar, "qxl.vram32", &qxl->vram_bar,
+    memory_region_init_alias(&qxl->vram32_bar, NULL, "qxl.vram32", &qxl->vram_bar,
                              0, qxl->vram32_size);
 
-    memory_region_init_io(&qxl->io_bar, &qxl_io_ops, qxl,
+    memory_region_init_io(&qxl->io_bar, NULL, &qxl_io_ops, qxl,
                           "qxl-ioports", io_size);
     if (qxl->id == 0) {
         vga_dirty_log_start(&qxl->vga);
@@ -2093,7 +2093,7 @@ static int qxl_init_secondary(PCIDevice *dev)
 
     qxl->id = device_id++;
     qxl_init_ramsize(qxl);
-    memory_region_init_ram(&qxl->vga.vram, "qxl.vgavram", qxl->vga.vram_size);
+    memory_region_init_ram(&qxl->vga.vram, NULL, "qxl.vgavram", qxl->vga.vram_size);
     vmstate_register_ram(&qxl->vga.vram, &qxl->pci.qdev);
     qxl->vga.vram_ptr = memory_region_get_ram_ptr(&qxl->vga.vram);
     qxl->vga.con = graphic_console_init(DEVICE(dev), &qxl_ops, qxl);
diff --git a/hw/display/sm501.c b/hw/display/sm501.c
index f72e488..c75d6ac 100644
--- a/hw/display/sm501.c
+++ b/hw/display/sm501.c
@@ -1408,23 +1408,23 @@ void sm501_init(MemoryRegion *address_space_mem, uint32_t base,
     s->dc_crt_control = 0x00010000;
 
     /* allocate local memory */
-    memory_region_init_ram(&s->local_mem_region, "sm501.local",
+    memory_region_init_ram(&s->local_mem_region, NULL, "sm501.local",
                            local_mem_bytes);
     vmstate_register_ram_global(&s->local_mem_region);
     s->local_mem = memory_region_get_ram_ptr(&s->local_mem_region);
     memory_region_add_subregion(address_space_mem, base, &s->local_mem_region);
 
     /* map mmio */
-    memory_region_init_io(sm501_system_config, &sm501_system_config_ops, s,
+    memory_region_init_io(sm501_system_config, NULL, &sm501_system_config_ops, s,
                           "sm501-system-config", 0x6c);
     memory_region_add_subregion(address_space_mem, base + MMIO_BASE_OFFSET,
                                 sm501_system_config);
-    memory_region_init_io(sm501_disp_ctrl, &sm501_disp_ctrl_ops, s,
+    memory_region_init_io(sm501_disp_ctrl, NULL, &sm501_disp_ctrl_ops, s,
                           "sm501-disp-ctrl", 0x1000);
     memory_region_add_subregion(address_space_mem,
                                 base + MMIO_BASE_OFFSET + SM501_DC,
                                 sm501_disp_ctrl);
-    memory_region_init_io(sm501_2d_engine, &sm501_2d_engine_ops, s,
+    memory_region_init_io(sm501_2d_engine, NULL, &sm501_2d_engine_ops, s,
                           "sm501-2d-engine", 0x54);
     memory_region_add_subregion(address_space_mem,
                                 base + MMIO_BASE_OFFSET + SM501_2D_ENGINE,
diff --git a/hw/display/tc6393xb.c b/hw/display/tc6393xb.c
index 0cb87bc..3dd9b98 100644
--- a/hw/display/tc6393xb.c
+++ b/hw/display/tc6393xb.c
@@ -578,10 +578,10 @@ TC6393xbState *tc6393xb_init(MemoryRegion *sysmem, uint32_t base, qemu_irq irq)
     nand = drive_get(IF_MTD, 0, 0);
     s->flash = nand_init(nand ? nand->bdrv : NULL, NAND_MFR_TOSHIBA, 0x76);
 
-    memory_region_init_io(&s->iomem, &tc6393xb_ops, s, "tc6393xb", 0x10000);
+    memory_region_init_io(&s->iomem, NULL, &tc6393xb_ops, s, "tc6393xb", 0x10000);
     memory_region_add_subregion(sysmem, base, &s->iomem);
 
-    memory_region_init_ram(&s->vram, "tc6393xb.vram", 0x100000);
+    memory_region_init_ram(&s->vram, NULL, "tc6393xb.vram", 0x100000);
     vmstate_register_ram_global(&s->vram);
     s->vram_ptr = memory_region_get_ram_ptr(&s->vram);
     memory_region_add_subregion(sysmem, base + 0x100000, &s->vram);
diff --git a/hw/display/tcx.c b/hw/display/tcx.c
index 995641c..24b5478 100644
--- a/hw/display/tcx.c
+++ b/hw/display/tcx.c
@@ -528,7 +528,7 @@ static int tcx_init1(SysBusDevice *dev)
     int size;
     uint8_t *vram_base;
 
-    memory_region_init_ram(&s->vram_mem, "tcx.vram",
+    memory_region_init_ram(&s->vram_mem, NULL, "tcx.vram",
                            s->vram_size * (1 + 4 + 4));
     vmstate_register_ram_global(&s->vram_mem);
     vram_base = memory_region_get_ram_ptr(&s->vram_mem);
@@ -536,21 +536,21 @@ static int tcx_init1(SysBusDevice *dev)
     /* 8-bit plane */
     s->vram = vram_base;
     size = s->vram_size;
-    memory_region_init_alias(&s->vram_8bit, "tcx.vram.8bit",
+    memory_region_init_alias(&s->vram_8bit, NULL, "tcx.vram.8bit",
                              &s->vram_mem, vram_offset, size);
     sysbus_init_mmio(dev, &s->vram_8bit);
     vram_offset += size;
     vram_base += size;
 
     /* DAC */
-    memory_region_init_io(&s->dac, &tcx_dac_ops, s, "tcx.dac", TCX_DAC_NREGS);
+    memory_region_init_io(&s->dac, NULL, &tcx_dac_ops, s, "tcx.dac", TCX_DAC_NREGS);
     sysbus_init_mmio(dev, &s->dac);
 
     /* TEC (dummy) */
-    memory_region_init_io(&s->tec, &dummy_ops, s, "tcx.tec", TCX_TEC_NREGS);
+    memory_region_init_io(&s->tec, NULL, &dummy_ops, s, "tcx.tec", TCX_TEC_NREGS);
     sysbus_init_mmio(dev, &s->tec);
     /* THC: NetBSD writes here even with 8-bit display: dummy */
-    memory_region_init_io(&s->thc24, &dummy_ops, s, "tcx.thc24",
+    memory_region_init_io(&s->thc24, NULL, &dummy_ops, s, "tcx.thc24",
                           TCX_THC_NREGS_24);
     sysbus_init_mmio(dev, &s->thc24);
 
@@ -559,7 +559,7 @@ static int tcx_init1(SysBusDevice *dev)
         size = s->vram_size * 4;
         s->vram24 = (uint32_t *)vram_base;
         s->vram24_offset = vram_offset;
-        memory_region_init_alias(&s->vram_24bit, "tcx.vram.24bit",
+        memory_region_init_alias(&s->vram_24bit, NULL, "tcx.vram.24bit",
                                  &s->vram_mem, vram_offset, size);
         sysbus_init_mmio(dev, &s->vram_24bit);
         vram_offset += size;
@@ -569,14 +569,14 @@ static int tcx_init1(SysBusDevice *dev)
         size = s->vram_size * 4;
         s->cplane = (uint32_t *)vram_base;
         s->cplane_offset = vram_offset;
-        memory_region_init_alias(&s->vram_cplane, "tcx.vram.cplane",
+        memory_region_init_alias(&s->vram_cplane, NULL, "tcx.vram.cplane",
                                  &s->vram_mem, vram_offset, size);
         sysbus_init_mmio(dev, &s->vram_cplane);
 
         s->con = graphic_console_init(DEVICE(dev), &tcx24_ops, s);
     } else {
         /* THC 8 bit (dummy) */
-        memory_region_init_io(&s->thc8, &dummy_ops, s, "tcx.thc8",
+        memory_region_init_io(&s->thc8, NULL, &dummy_ops, s, "tcx.thc8",
                               TCX_THC_NREGS_8);
         sysbus_init_mmio(dev, &s->thc8);
 
diff --git a/hw/display/vga-isa-mm.c b/hw/display/vga-isa-mm.c
index ceeb92f..95707a8 100644
--- a/hw/display/vga-isa-mm.c
+++ b/hw/display/vga-isa-mm.c
@@ -105,13 +105,13 @@ static void vga_mm_init(ISAVGAMMState *s, hwaddr vram_base,
 
     s->it_shift = it_shift;
     s_ioport_ctrl = g_malloc(sizeof(*s_ioport_ctrl));
-    memory_region_init_io(s_ioport_ctrl, &vga_mm_ctrl_ops, s,
+    memory_region_init_io(s_ioport_ctrl, NULL, &vga_mm_ctrl_ops, s,
                           "vga-mm-ctrl", 0x100000);
     memory_region_set_flush_coalesced(s_ioport_ctrl);
 
     vga_io_memory = g_malloc(sizeof(*vga_io_memory));
     /* XXX: endianness? */
-    memory_region_init_io(vga_io_memory, &vga_mem_ops, &s->vga,
+    memory_region_init_io(vga_io_memory, NULL, &vga_mem_ops, &s->vga,
                           "vga-mem", 0x20000);
 
     vmstate_register(NULL, 0, &vmstate_vga_common, s);
diff --git a/hw/display/vga-pci.c b/hw/display/vga-pci.c
index cea8db7..23d5b56 100644
--- a/hw/display/vga-pci.c
+++ b/hw/display/vga-pci.c
@@ -157,10 +157,10 @@ static int pci_std_vga_initfn(PCIDevice *dev)
 
     /* mmio bar for vga register access */
     if (d->flags & (1 << PCI_VGA_FLAG_ENABLE_MMIO)) {
-        memory_region_init(&d->mmio, "vga.mmio", 4096);
-        memory_region_init_io(&d->ioport, &pci_vga_ioport_ops, d,
+        memory_region_init(&d->mmio, NULL, "vga.mmio", 4096);
+        memory_region_init_io(&d->ioport, NULL, &pci_vga_ioport_ops, d,
                               "vga ioports remapped", PCI_VGA_IOPORT_SIZE);
-        memory_region_init_io(&d->bochs, &pci_vga_bochs_ops, d,
+        memory_region_init_io(&d->bochs, NULL, &pci_vga_bochs_ops, d,
                               "bochs dispi interface", PCI_VGA_BOCHS_SIZE);
 
         memory_region_add_subregion(&d->mmio, PCI_VGA_IOPORT_OFFSET,
diff --git a/hw/display/vga.c b/hw/display/vga.c
index 21a108d..21e3763 100644
--- a/hw/display/vga.c
+++ b/hw/display/vga.c
@@ -198,7 +198,7 @@ static void vga_update_memory_access(VGACommonState *s)
         }
         base += isa_mem_base;
         region = g_malloc(sizeof(*region));
-        memory_region_init_alias(region, "vga.chain4", &s->vram, offset, size);
+        memory_region_init_alias(region, NULL, "vga.chain4", &s->vram, offset, size);
         memory_region_add_subregion_overlap(s->legacy_address_space, base,
                                             region, 2);
         s->chain4_alias = region;
@@ -2292,7 +2292,7 @@ void vga_common_init(VGACommonState *s)
     s->vram_size_mb = s->vram_size >> 20;
 
     s->is_vbe_vmstate = 1;
-    memory_region_init_ram(&s->vram, "vga.vram", s->vram_size);
+    memory_region_init_ram(&s->vram, NULL, "vga.vram", s->vram_size);
     vmstate_register_ram_global(&s->vram);
     xen_register_framebuffer(&s->vram);
     s->vram_ptr = memory_region_get_ram_ptr(&s->vram);
@@ -2343,7 +2343,7 @@ MemoryRegion *vga_init_io(VGACommonState *s,
     *vbe_ports = vbe_portio_list;
 
     vga_mem = g_malloc(sizeof(*vga_mem));
-    memory_region_init_io(vga_mem, &vga_mem_ops, s,
+    memory_region_init_io(vga_mem, NULL, &vga_mem_ops, s,
                           "vga-lowmem", 0x20000);
     memory_region_set_flush_coalesced(vga_mem);
 
@@ -2385,7 +2385,7 @@ void vga_init_vbe(VGACommonState *s, MemoryRegion *system_memory)
     /* With pc-0.12 and below we map both the PCI BAR and the fixed VBE region,
      * so use an alias to avoid double-mapping the same region.
      */
-    memory_region_init_alias(&s->vram_vbe, "vram.vbe",
+    memory_region_init_alias(&s->vram_vbe, NULL, "vram.vbe",
                              &s->vram, 0, memory_region_size(&s->vram));
     /* XXX: use optimized standard vga accesses */
     memory_region_add_subregion(system_memory,
diff --git a/hw/display/vmware_vga.c b/hw/display/vmware_vga.c
index ec41681..05be1fa 100644
--- a/hw/display/vmware_vga.c
+++ b/hw/display/vmware_vga.c
@@ -1194,7 +1194,7 @@ static void vmsvga_init(DeviceState *dev, struct vmsvga_state_s *s,
     s->vga.con = graphic_console_init(dev, &vmsvga_ops, s);
 
     s->fifo_size = SVGA_FIFO_SIZE;
-    memory_region_init_ram(&s->fifo_ram, "vmsvga.fifo", s->fifo_size);
+    memory_region_init_ram(&s->fifo_ram, NULL, "vmsvga.fifo", s->fifo_size);
     vmstate_register_ram_global(&s->fifo_ram);
     s->fifo_ptr = memory_region_get_ram_ptr(&s->fifo_ram);
 
@@ -1257,7 +1257,7 @@ static int pci_vmsvga_initfn(PCIDevice *dev)
     s->card.config[PCI_LATENCY_TIMER] = 0x40;           /* Latency timer */
     s->card.config[PCI_INTERRUPT_LINE] = 0xff;          /* End */
 
-    memory_region_init_io(&s->io_bar, &vmsvga_io_ops, &s->chip,
+    memory_region_init_io(&s->io_bar, NULL, &vmsvga_io_ops, &s->chip,
                           "vmsvga-io", 0x10);
     memory_region_set_flush_coalesced(&s->io_bar);
     pci_register_bar(&s->card, 0, PCI_BASE_ADDRESS_SPACE_IO, &s->io_bar);
diff --git a/hw/dma/etraxfs_dma.c b/hw/dma/etraxfs_dma.c
index 6a8c222..3599513 100644
--- a/hw/dma/etraxfs_dma.c
+++ b/hw/dma/etraxfs_dma.c
@@ -773,7 +773,7 @@ void *etraxfs_dmac_init(hwaddr base, int nr_channels)
 	ctrl->nr_channels = nr_channels;
 	ctrl->channels = g_malloc0(sizeof ctrl->channels[0] * nr_channels);
 
-	memory_region_init_io(&ctrl->mmio, &dma_ops, ctrl, "etraxfs-dma",
+	memory_region_init_io(&ctrl->mmio, NULL, &dma_ops, ctrl, "etraxfs-dma",
 			      nr_channels * 0x2000);
 	memory_region_add_subregion(get_system_memory(), base, &ctrl->mmio);
 
diff --git a/hw/dma/i8257.c b/hw/dma/i8257.c
index eb60d45..4490372 100644
--- a/hw/dma/i8257.c
+++ b/hw/dma/i8257.c
@@ -523,7 +523,7 @@ static void dma_init2(struct dma_cont *d, int base, int dshift,
     d->dshift = dshift;
     d->cpu_request_exit = cpu_request_exit;
 
-    memory_region_init_io(&d->channel_io, &channel_io_ops, d,
+    memory_region_init_io(&d->channel_io, NULL, &channel_io_ops, d,
                           "dma-chan", 8 << d->dshift);
     memory_region_add_subregion(isa_address_space_io(NULL),
                                 base, &d->channel_io);
@@ -535,7 +535,7 @@ static void dma_init2(struct dma_cont *d, int base, int dshift,
                                  "dma-pageh");
     }
 
-    memory_region_init_io(&d->cont_io, &cont_io_ops, d, "dma-cont",
+    memory_region_init_io(&d->cont_io, NULL, &cont_io_ops, d, "dma-cont",
                           8 << d->dshift);
     memory_region_add_subregion(isa_address_space_io(NULL),
                                 base + (8 << d->dshift), &d->cont_io);
diff --git a/hw/dma/omap_dma.c b/hw/dma/omap_dma.c
index 184fcee..a81ffc4 100644
--- a/hw/dma/omap_dma.c
+++ b/hw/dma/omap_dma.c
@@ -1663,7 +1663,7 @@ struct soc_dma_s *omap_dma_init(hwaddr base, qemu_irq *irqs,
     omap_dma_reset(s->dma);
     omap_dma_clk_update(s, 0, 1);
 
-    memory_region_init_io(&s->iomem, &omap_dma_ops, s, "omap.dma", memsize);
+    memory_region_init_io(&s->iomem, NULL, &omap_dma_ops, s, "omap.dma", memsize);
     memory_region_add_subregion(sysmem, base, &s->iomem);
 
     mpu->drq = s->dma->drq;
@@ -2085,7 +2085,7 @@ struct soc_dma_s *omap_dma4_init(hwaddr base, qemu_irq *irqs,
     omap_dma_reset(s->dma);
     omap_dma_clk_update(s, 0, !!s->dma->freq);
 
-    memory_region_init_io(&s->iomem, &omap_dma4_ops, s, "omap.dma4", 0x1000);
+    memory_region_init_io(&s->iomem, NULL, &omap_dma4_ops, s, "omap.dma4", 0x1000);
     memory_region_add_subregion(sysmem, base, &s->iomem);
 
     mpu->drq = s->dma->drq;
diff --git a/hw/dma/pl080.c b/hw/dma/pl080.c
index 00b66b4..588c7b2 100644
--- a/hw/dma/pl080.c
+++ b/hw/dma/pl080.c
@@ -359,7 +359,7 @@ static int pl08x_init(SysBusDevice *dev, int nchannels)
 {
     pl080_state *s = FROM_SYSBUS(pl080_state, dev);
 
-    memory_region_init_io(&s->iomem, &pl080_ops, s, "pl080", 0x1000);
+    memory_region_init_io(&s->iomem, NULL, &pl080_ops, s, "pl080", 0x1000);
     sysbus_init_mmio(dev, &s->iomem);
     sysbus_init_irq(dev, &s->irq);
     s->nchannels = nchannels;
diff --git a/hw/dma/pl330.c b/hw/dma/pl330.c
index 044c087..b366f8a 100644
--- a/hw/dma/pl330.c
+++ b/hw/dma/pl330.c
@@ -1528,7 +1528,7 @@ static void pl330_realize(DeviceState *dev, Error **errp)
     PL330State *s = PL330(dev);
 
     sysbus_init_irq(SYS_BUS_DEVICE(dev), &s->irq_abort);
-    memory_region_init_io(&s->iomem, &pl330_ops, s, "dma", PL330_IOMEM_SIZE);
+    memory_region_init_io(&s->iomem, NULL, &pl330_ops, s, "dma", PL330_IOMEM_SIZE);
     sysbus_init_mmio(SYS_BUS_DEVICE(dev), &s->iomem);
 
     s->timer = qemu_new_timer_ns(vm_clock, pl330_exec_cycle_timer, s);
diff --git a/hw/dma/puv3_dma.c b/hw/dma/puv3_dma.c
index 32844b5..787e9a1 100644
--- a/hw/dma/puv3_dma.c
+++ b/hw/dma/puv3_dma.c
@@ -80,7 +80,7 @@ static int puv3_dma_init(SysBusDevice *dev)
         s->reg_CFG[i] = 0x0;
     }
 
-    memory_region_init_io(&s->iomem, &puv3_dma_ops, s, "puv3_dma",
+    memory_region_init_io(&s->iomem, NULL, &puv3_dma_ops, s, "puv3_dma",
             PUV3_REGS_OFFSET);
     sysbus_init_mmio(dev, &s->iomem);
 
diff --git a/hw/dma/pxa2xx_dma.c b/hw/dma/pxa2xx_dma.c
index b60569f..43e2dc3 100644
--- a/hw/dma/pxa2xx_dma.c
+++ b/hw/dma/pxa2xx_dma.c
@@ -465,7 +465,7 @@ static int pxa2xx_dma_init(SysBusDevice *dev)
 
     qdev_init_gpio_in(&dev->qdev, pxa2xx_dma_request, PXA2XX_DMA_NUM_REQUESTS);
 
-    memory_region_init_io(&s->iomem, &pxa2xx_dma_ops, s,
+    memory_region_init_io(&s->iomem, NULL, &pxa2xx_dma_ops, s,
                           "pxa2xx.dma", 0x00010000);
     sysbus_init_mmio(dev, &s->iomem);
     sysbus_init_irq(dev, &s->irq);
diff --git a/hw/dma/rc4030.c b/hw/dma/rc4030.c
index 03f92f1..4ec433f 100644
--- a/hw/dma/rc4030.c
+++ b/hw/dma/rc4030.c
@@ -814,10 +814,10 @@ void *rc4030_init(qemu_irq timer, qemu_irq jazz_bus,
     register_savevm(NULL, "rc4030", 0, 2, rc4030_save, rc4030_load, s);
     rc4030_reset(s);
 
-    memory_region_init_io(&s->iomem_chipset, &rc4030_ops, s,
+    memory_region_init_io(&s->iomem_chipset, NULL, &rc4030_ops, s,
                           "rc4030.chipset", 0x300);
     memory_region_add_subregion(sysmem, 0x80000000, &s->iomem_chipset);
-    memory_region_init_io(&s->iomem_jazzio, &jazzio_ops, s,
+    memory_region_init_io(&s->iomem_jazzio, NULL, &jazzio_ops, s,
                           "rc4030.jazzio", 0x00001000);
     memory_region_add_subregion(sysmem, 0xf0000000, &s->iomem_jazzio);
 
diff --git a/hw/dma/sparc32_dma.c b/hw/dma/sparc32_dma.c
index fd21533..4abb024 100644
--- a/hw/dma/sparc32_dma.c
+++ b/hw/dma/sparc32_dma.c
@@ -274,7 +274,7 @@ static int sparc32_dma_init1(SysBusDevice *dev)
     sysbus_init_irq(dev, &s->irq);
 
     reg_size = s->is_ledma ? DMA_ETH_SIZE : DMA_SIZE;
-    memory_region_init_io(&s->iomem, &dma_mem_ops, s, "dma", reg_size);
+    memory_region_init_io(&s->iomem, NULL, &dma_mem_ops, s, "dma", reg_size);
     sysbus_init_mmio(dev, &s->iomem);
 
     qdev_init_gpio_in(&dev->qdev, dma_set_irq, 1);
diff --git a/hw/dma/sun4m_iommu.c b/hw/dma/sun4m_iommu.c
index 8312bff..eafb991 100644
--- a/hw/dma/sun4m_iommu.c
+++ b/hw/dma/sun4m_iommu.c
@@ -349,7 +349,7 @@ static int iommu_init1(SysBusDevice *dev)
 
     sysbus_init_irq(dev, &s->irq);
 
-    memory_region_init_io(&s->iomem, &iommu_mem_ops, s, "iommu",
+    memory_region_init_io(&s->iomem, NULL, &iommu_mem_ops, s, "iommu",
                           IOMMU_NREGS * sizeof(uint32_t));
     sysbus_init_mmio(dev, &s->iomem);
 
diff --git a/hw/dma/xilinx_axidma.c b/hw/dma/xilinx_axidma.c
index 50054cf..bdce635 100644
--- a/hw/dma/xilinx_axidma.c
+++ b/hw/dma/xilinx_axidma.c
@@ -590,7 +590,7 @@ static void xilinx_axidma_init(Object *obj)
     sysbus_init_irq(sbd, &s->streams[0].irq);
     sysbus_init_irq(sbd, &s->streams[1].irq);
 
-    memory_region_init_io(&s->iomem, &axidma_ops, s,
+    memory_region_init_io(&s->iomem, NULL, &axidma_ops, s,
                           "xlnx.axi-dma", R_MAX * 4 * 2);
     sysbus_init_mmio(sbd, &s->iomem);
 }
diff --git a/hw/gpio/omap_gpio.c b/hw/gpio/omap_gpio.c
index f5eeaea..13399f9 100644
--- a/hw/gpio/omap_gpio.c
+++ b/hw/gpio/omap_gpio.c
@@ -677,7 +677,7 @@ static int omap_gpio_init(SysBusDevice *dev)
     qdev_init_gpio_in(&dev->qdev, omap_gpio_set, 16);
     qdev_init_gpio_out(&dev->qdev, s->omap1.handler, 16);
     sysbus_init_irq(dev, &s->omap1.irq);
-    memory_region_init_io(&s->iomem, &omap_gpio_ops, &s->omap1,
+    memory_region_init_io(&s->iomem, NULL, &omap_gpio_ops, &s->omap1,
                           "omap.gpio", 0x1000);
     sysbus_init_mmio(dev, &s->iomem);
     return 0;
@@ -692,7 +692,7 @@ static int omap2_gpio_init(SysBusDevice *dev)
     }
     if (s->mpu_model < omap3430) {
         s->modulecount = (s->mpu_model < omap2430) ? 4 : 5;
-        memory_region_init_io(&s->iomem, &omap2_gpif_top_ops, s,
+        memory_region_init_io(&s->iomem, NULL, &omap2_gpif_top_ops, s,
                               "omap2.gpio", 0x1000);
         sysbus_init_mmio(dev, &s->iomem);
     } else {
@@ -712,7 +712,7 @@ static int omap2_gpio_init(SysBusDevice *dev)
         sysbus_init_irq(dev, &m->irq[0]); /* mpu irq */
         sysbus_init_irq(dev, &m->irq[1]); /* dsp irq */
         sysbus_init_irq(dev, &m->wkup);
-        memory_region_init_io(&m->iomem, &omap2_gpio_module_ops, m,
+        memory_region_init_io(&m->iomem, NULL, &omap2_gpio_module_ops, m,
                               "omap.gpio-module", 0x1000);
         sysbus_init_mmio(dev, &m->iomem);
     }
diff --git a/hw/gpio/pl061.c b/hw/gpio/pl061.c
index 74bc109..d0dd636 100644
--- a/hw/gpio/pl061.c
+++ b/hw/gpio/pl061.c
@@ -276,7 +276,7 @@ static int pl061_init(SysBusDevice *dev, const unsigned char *id)
 {
     pl061_state *s = FROM_SYSBUS(pl061_state, dev);
     s->id = id;
-    memory_region_init_io(&s->iomem, &pl061_ops, s, "pl061", 0x1000);
+    memory_region_init_io(&s->iomem, NULL, &pl061_ops, s, "pl061", 0x1000);
     sysbus_init_mmio(dev, &s->iomem);
     sysbus_init_irq(dev, &s->irq);
     qdev_init_gpio_in(&dev->qdev, pl061_set_irq, 8);
diff --git a/hw/gpio/puv3_gpio.c b/hw/gpio/puv3_gpio.c
index 5bab97e..333c920 100644
--- a/hw/gpio/puv3_gpio.c
+++ b/hw/gpio/puv3_gpio.c
@@ -112,7 +112,7 @@ static int puv3_gpio_init(SysBusDevice *dev)
     sysbus_init_irq(dev, &s->irq[PUV3_IRQS_GPIOLOW7]);
     sysbus_init_irq(dev, &s->irq[PUV3_IRQS_GPIOHIGH]);
 
-    memory_region_init_io(&s->iomem, &puv3_gpio_ops, s, "puv3_gpio",
+    memory_region_init_io(&s->iomem, NULL, &puv3_gpio_ops, s, "puv3_gpio",
             PUV3_REGS_OFFSET);
     sysbus_init_mmio(dev, &s->iomem);
 
diff --git a/hw/gpio/zaurus.c b/hw/gpio/zaurus.c
index c6cdef3..a0e18c3 100644
--- a/hw/gpio/zaurus.c
+++ b/hw/gpio/zaurus.c
@@ -169,7 +169,7 @@ static int scoop_init(SysBusDevice *dev)
     s->status = 0x02;
     qdev_init_gpio_out(&s->busdev.qdev, s->handler, 16);
     qdev_init_gpio_in(&s->busdev.qdev, scoop_gpio_set, 16);
-    memory_region_init_io(&s->iomem, &scoop_ops, s, "scoop", 0x1000);
+    memory_region_init_io(&s->iomem, NULL, &scoop_ops, s, "scoop", 0x1000);
 
     sysbus_init_mmio(dev, &s->iomem);
 
diff --git a/hw/i2c/bitbang_i2c.c b/hw/i2c/bitbang_i2c.c
index 854b8e1..f550ba4 100644
--- a/hw/i2c/bitbang_i2c.c
+++ b/hw/i2c/bitbang_i2c.c
@@ -209,7 +209,7 @@ static int gpio_i2c_init(SysBusDevice *dev)
     GPIOI2CState *s = FROM_SYSBUS(GPIOI2CState, dev);
     i2c_bus *bus;
 
-    memory_region_init(&s->dummy_iomem, "gpio_i2c", 0);
+    memory_region_init(&s->dummy_iomem, NULL, "gpio_i2c", 0);
     sysbus_init_mmio(dev, &s->dummy_iomem);
 
     bus = i2c_init_bus(&dev->qdev, "i2c");
diff --git a/hw/i2c/exynos4210_i2c.c b/hw/i2c/exynos4210_i2c.c
index 196f889..bc6eb34 100644
--- a/hw/i2c/exynos4210_i2c.c
+++ b/hw/i2c/exynos4210_i2c.c
@@ -301,7 +301,7 @@ static int exynos4210_i2c_realize(SysBusDevice *dev)
 {
     Exynos4210I2CState *s = EXYNOS4_I2C(dev);
 
-    memory_region_init_io(&s->iomem, &exynos4210_i2c_ops, s, TYPE_EXYNOS4_I2C,
+    memory_region_init_io(&s->iomem, NULL, &exynos4210_i2c_ops, s, TYPE_EXYNOS4_I2C,
                           EXYNOS4_I2C_MEM_SIZE);
     sysbus_init_mmio(dev, &s->iomem);
     sysbus_init_irq(dev, &s->irq);
diff --git a/hw/i2c/omap_i2c.c b/hw/i2c/omap_i2c.c
index efb2254..1a8b39c 100644
--- a/hw/i2c/omap_i2c.c
+++ b/hw/i2c/omap_i2c.c
@@ -448,7 +448,7 @@ static int omap_i2c_init(SysBusDevice *dev)
     sysbus_init_irq(dev, &s->irq);
     sysbus_init_irq(dev, &s->drq[0]);
     sysbus_init_irq(dev, &s->drq[1]);
-    memory_region_init_io(&s->iomem, &omap_i2c_ops, s, "omap.i2c",
+    memory_region_init_io(&s->iomem, NULL, &omap_i2c_ops, s, "omap.i2c",
                           (s->revision < OMAP2_INTR_REV) ? 0x800 : 0x1000);
     sysbus_init_mmio(dev, &s->iomem);
     s->bus = i2c_init_bus(&dev->qdev, NULL);
diff --git a/hw/i2c/pm_smbus.c b/hw/i2c/pm_smbus.c
index 0b5bb89..f425ad8 100644
--- a/hw/i2c/pm_smbus.c
+++ b/hw/i2c/pm_smbus.c
@@ -181,5 +181,5 @@ static const MemoryRegionOps pm_smbus_ops = {
 void pm_smbus_init(DeviceState *parent, PMSMBus *smb)
 {
     smb->smbus = i2c_init_bus(parent, "i2c");
-    memory_region_init_io(&smb->io, &pm_smbus_ops, smb, "pm-smbus", 64);
+    memory_region_init_io(&smb->io, NULL, &pm_smbus_ops, smb, "pm-smbus", 64);
 }
diff --git a/hw/i2c/versatile_i2c.c b/hw/i2c/versatile_i2c.c
index e09c83d..a239963 100644
--- a/hw/i2c/versatile_i2c.c
+++ b/hw/i2c/versatile_i2c.c
@@ -79,7 +79,7 @@ static int versatile_i2c_init(SysBusDevice *dev)
 
     bus = i2c_init_bus(&dev->qdev, "i2c");
     s->bitbang = bitbang_i2c_init(bus);
-    memory_region_init_io(&s->iomem, &versatile_i2c_ops, s,
+    memory_region_init_io(&s->iomem, NULL, &versatile_i2c_ops, s,
                           "versatile_i2c", 0x1000);
     sysbus_init_mmio(dev, &s->iomem);
     return 0;
diff --git a/hw/i386/kvm/apic.c b/hw/i386/kvm/apic.c
index 8f80425..bf48d75 100644
--- a/hw/i386/kvm/apic.c
+++ b/hw/i386/kvm/apic.c
@@ -173,7 +173,7 @@ static const MemoryRegionOps kvm_apic_io_ops = {
 
 static void kvm_apic_init(APICCommonState *s)
 {
-    memory_region_init_io(&s->io_memory, &kvm_apic_io_ops, s, "kvm-apic-msi",
+    memory_region_init_io(&s->io_memory, NULL, &kvm_apic_io_ops, s, "kvm-apic-msi",
                           APIC_SPACE_SIZE);
 
     if (kvm_has_gsi_routing()) {
diff --git a/hw/i386/kvm/i8254.c b/hw/i386/kvm/i8254.c
index 93a3669..c1f4094 100644
--- a/hw/i386/kvm/i8254.c
+++ b/hw/i386/kvm/i8254.c
@@ -288,7 +288,7 @@ static void kvm_pit_realizefn(DeviceState *dev, Error **errp)
         return;
     }
 
-    memory_region_init_reservation(&pit->ioports, "kvm-pit", 4);
+    memory_region_init_reservation(&pit->ioports, NULL, "kvm-pit", 4);
 
     qdev_init_gpio_in(dev, kvm_pit_irq_control, 1);
 
diff --git a/hw/i386/kvm/i8259.c b/hw/i386/kvm/i8259.c
index 1250224..53e3ca8 100644
--- a/hw/i386/kvm/i8259.c
+++ b/hw/i386/kvm/i8259.c
@@ -119,8 +119,8 @@ static void kvm_pic_realize(DeviceState *dev, Error **errp)
     PICCommonState *s = PIC_COMMON(dev);
     KVMPICClass *kpc = KVM_PIC_GET_CLASS(dev);
 
-    memory_region_init_reservation(&s->base_io, "kvm-pic", 2);
-    memory_region_init_reservation(&s->elcr_io, "kvm-elcr", 1);
+    memory_region_init_reservation(&s->base_io, NULL, "kvm-pic", 2);
+    memory_region_init_reservation(&s->elcr_io, NULL, "kvm-elcr", 1);
 
     kpc->parent_realize(dev, errp);
 }
diff --git a/hw/i386/kvm/ioapic.c b/hw/i386/kvm/ioapic.c
index a3bd519..9983c68 100644
--- a/hw/i386/kvm/ioapic.c
+++ b/hw/i386/kvm/ioapic.c
@@ -128,7 +128,7 @@ static void kvm_ioapic_set_irq(void *opaque, int irq, int level)
 
 static void kvm_ioapic_init(IOAPICCommonState *s, int instance_no)
 {
-    memory_region_init_reservation(&s->io_memory, "kvm-ioapic", 0x1000);
+    memory_region_init_reservation(&s->io_memory, NULL, "kvm-ioapic", 0x1000);
 
     qdev_init_gpio_in(&s->busdev.qdev, kvm_ioapic_set_irq, IOAPIC_NUM_PINS);
 }
diff --git a/hw/i386/kvm/pci-assign.c b/hw/i386/kvm/pci-assign.c
index 1fb7ad4..f1a5554 100644
--- a/hw/i386/kvm/pci-assign.c
+++ b/hw/i386/kvm/pci-assign.c
@@ -298,7 +298,7 @@ static void assigned_dev_iomem_setup(PCIDevice *pci_dev, int region_num,
     PCIRegion *real_region = &r_dev->real_device.regions[region_num];
 
     if (e_size > 0) {
-        memory_region_init(&region->container, "assigned-dev-container",
+        memory_region_init(&region->container, NULL, "assigned-dev-container",
                            e_size);
         memory_region_add_subregion(&region->container, 0, &region->real_iomem);
 
@@ -329,8 +329,8 @@ static void assigned_dev_ioport_setup(PCIDevice *pci_dev, int region_num,
     AssignedDevRegion *region = &r_dev->v_addrs[region_num];
 
     region->e_size = size;
-    memory_region_init(&region->container, "assigned-dev-container", size);
-    memory_region_init_io(&region->real_iomem, &assigned_dev_ioport_ops,
+    memory_region_init(&region->container, NULL, "assigned-dev-container", size);
+    memory_region_init_io(&region->real_iomem, NULL, &assigned_dev_ioport_ops,
                           r_dev->v_addrs + region_num,
                           "assigned-dev-iomem", size);
     memory_region_add_subregion(&region->container, 0, &region->real_iomem);
@@ -478,7 +478,7 @@ static int assigned_dev_register_regions(PCIRegion *io_regions,
                              "4K.  You might experience some performance hit "
                              "due to that.",
                              i, cur_region->base_addr, cur_region->size);
-                memory_region_init_io(&pci_dev->v_addrs[i].real_iomem,
+                memory_region_init_io(&pci_dev->v_addrs[i].real_iomem, NULL,
                                       &slow_bar_ops, &pci_dev->v_addrs[i],
                                       "assigned-dev-slow-bar",
                                       cur_region->size);
@@ -487,7 +487,7 @@ static int assigned_dev_register_regions(PCIRegion *io_regions,
                 char name[32];
                 snprintf(name, sizeof(name), "%s.bar%d",
                          object_get_typename(OBJECT(pci_dev)), i);
-                memory_region_init_ram_ptr(&pci_dev->v_addrs[i].real_iomem,
+                memory_region_init_ram_ptr(&pci_dev->v_addrs[i].real_iomem, NULL,
                                            name, cur_region->size,
                                            virtbase);
                 vmstate_register_ram(&pci_dev->v_addrs[i].real_iomem,
@@ -1650,7 +1650,7 @@ static int assigned_dev_register_msix_mmio(AssignedDevice *dev)
 
     assigned_dev_msix_reset(dev);
 
-    memory_region_init_io(&dev->mmio, &assigned_dev_msix_mmio_ops, dev,
+    memory_region_init_io(&dev->mmio, NULL, &assigned_dev_msix_mmio_ops, dev,
                           "assigned-dev-msix", MSIX_PAGE_SIZE);
     return 0;
 }
@@ -1916,7 +1916,7 @@ static void assigned_dev_load_option_rom(AssignedDevice *dev)
 
     snprintf(name, sizeof(name), "%s.rom",
             object_get_typename(OBJECT(dev)));
-    memory_region_init_ram(&dev->dev.rom, name, st.st_size);
+    memory_region_init_ram(&dev->dev.rom, NULL, name, st.st_size);
     vmstate_register_ram(&dev->dev.rom, &dev->dev.qdev);
     ptr = memory_region_get_ram_ptr(&dev->dev.rom);
     memset(ptr, 0xff, st.st_size);
diff --git a/hw/i386/kvmvapic.c b/hw/i386/kvmvapic.c
index 655483b..953fc74 100644
--- a/hw/i386/kvmvapic.c
+++ b/hw/i386/kvmvapic.c
@@ -601,7 +601,7 @@ static void vapic_map_rom_writable(VAPICROMState *s)
     rom_paddr &= TARGET_PAGE_MASK;
     rom_size = TARGET_PAGE_ALIGN(rom_size);
 
-    memory_region_init_alias(&s->rom, "kvmvapic-rom", section.mr, rom_paddr,
+    memory_region_init_alias(&s->rom, NULL, "kvmvapic-rom", section.mr, rom_paddr,
                              rom_size);
     memory_region_add_subregion_overlap(as, rom_paddr, &s->rom, 1000);
     s->rom_mapped_writable = true;
@@ -702,7 +702,7 @@ static int vapic_init(SysBusDevice *dev)
 {
     VAPICROMState *s = VAPIC(dev);
 
-    memory_region_init_io(&s->io, &vapic_ops, s, "kvmvapic", 2);
+    memory_region_init_io(&s->io, NULL, &vapic_ops, s, "kvmvapic", 2);
     sysbus_add_io(dev, VAPIC_IO_PORT, &s->io);
     sysbus_init_ioports(dev, VAPIC_IO_PORT, 2);
 
diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index 5e8f143..5aa2afa 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -525,7 +525,7 @@ static void port92_initfn(Object *obj)
 {
     Port92State *s = PORT92(obj);
 
-    memory_region_init_io(&s->io, &port92_ops, s, "port92", 1);
+    memory_region_init_io(&s->io, NULL, &port92_ops, s, "port92", 1);
 
     s->outport = 0;
 }
@@ -1044,17 +1044,17 @@ FWCfgState *pc_memory_init(MemoryRegion *system_memory,
      * with older qemus that used qemu_ram_alloc().
      */
     ram = g_malloc(sizeof(*ram));
-    memory_region_init_ram(ram, "pc.ram",
+    memory_region_init_ram(ram, NULL, "pc.ram",
                            below_4g_mem_size + above_4g_mem_size);
     vmstate_register_ram_global(ram);
     *ram_memory = ram;
     ram_below_4g = g_malloc(sizeof(*ram_below_4g));
-    memory_region_init_alias(ram_below_4g, "ram-below-4g", ram,
+    memory_region_init_alias(ram_below_4g, NULL, "ram-below-4g", ram,
                              0, below_4g_mem_size);
     memory_region_add_subregion(system_memory, 0, ram_below_4g);
     if (above_4g_mem_size > 0) {
         ram_above_4g = g_malloc(sizeof(*ram_above_4g));
-        memory_region_init_alias(ram_above_4g, "ram-above-4g", ram,
+        memory_region_init_alias(ram_above_4g, NULL, "ram-above-4g", ram,
                                  below_4g_mem_size, above_4g_mem_size);
         memory_region_add_subregion(system_memory, 0x100000000ULL,
                                     ram_above_4g);
@@ -1065,7 +1065,7 @@ FWCfgState *pc_memory_init(MemoryRegion *system_memory,
     pc_system_firmware_init(rom_memory);
 
     option_rom_mr = g_malloc(sizeof(*option_rom_mr));
-    memory_region_init_ram(option_rom_mr, "pc.rom", PC_ROM_SIZE);
+    memory_region_init_ram(option_rom_mr, NULL, "pc.rom", PC_ROM_SIZE);
     vmstate_register_ram_global(option_rom_mr);
     memory_region_add_subregion_overlap(rom_memory,
                                         PC_ROM_MIN_VGA,
@@ -1150,10 +1150,10 @@ void pc_basic_device_init(ISABus *isa_bus, qemu_irq *gsi,
     MemoryRegion *ioport80_io = g_new(MemoryRegion, 1);
     MemoryRegion *ioportF0_io = g_new(MemoryRegion, 1);
 
-    memory_region_init_io(ioport80_io, &ioport80_io_ops, NULL, "ioport80", 1);
+    memory_region_init_io(ioport80_io, NULL, &ioport80_io_ops, NULL, "ioport80", 1);
     memory_region_add_subregion(isa_bus->address_space_io, 0x80, ioport80_io);
 
-    memory_region_init_io(ioportF0_io, &ioportF0_io_ops, NULL, "ioportF0", 1);
+    memory_region_init_io(ioportF0_io, NULL, &ioportF0_io_ops, NULL, "ioportF0", 1);
     memory_region_add_subregion(isa_bus->address_space_io, 0xf0, ioportF0_io);
 
     /*
diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index fa59a0c..faf947e 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -117,7 +117,7 @@ static void pc_init1(MemoryRegion *system_memory,
 
     if (pci_enabled) {
         pci_memory = g_new(MemoryRegion, 1);
-        memory_region_init(pci_memory, "pci", INT64_MAX);
+        memory_region_init(pci_memory, NULL, "pci", INT64_MAX);
         rom_memory = pci_memory;
     } else {
         pci_memory = NULL;
diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
index bb0ce6a..e4cde04 100644
--- a/hw/i386/pc_q35.c
+++ b/hw/i386/pc_q35.c
@@ -98,7 +98,7 @@ static void pc_q35_init(QEMUMachineInitArgs *args)
     /* pci enabled */
     if (pci_enabled) {
         pci_memory = g_new(MemoryRegion, 1);
-        memory_region_init(pci_memory, "pci", INT64_MAX);
+        memory_region_init(pci_memory, NULL, "pci", INT64_MAX);
         rom_memory = pci_memory;
     } else {
         pci_memory = NULL;
diff --git a/hw/ide/ahci.c b/hw/ide/ahci.c
index 6b87549..e18e1b1 100644
--- a/hw/ide/ahci.c
+++ b/hw/ide/ahci.c
@@ -1156,8 +1156,8 @@ void ahci_init(AHCIState *s, DeviceState *qdev, AddressSpace *as, int ports)
     s->dev = g_malloc0(sizeof(AHCIDevice) * ports);
     ahci_reg_init(s);
     /* XXX BAR size should be 1k, but that breaks, so bump it to 4k for now */
-    memory_region_init_io(&s->mem, &ahci_mem_ops, s, "ahci", AHCI_MEM_BAR_SIZE);
-    memory_region_init_io(&s->idp, &ahci_idp_ops, s, "ahci-idp", 32);
+    memory_region_init_io(&s->mem, NULL, &ahci_mem_ops, s, "ahci", AHCI_MEM_BAR_SIZE);
+    memory_region_init_io(&s->idp, NULL, &ahci_idp_ops, s, "ahci-idp", 32);
 
     irqs = qemu_allocate_irqs(ahci_irq_set, s, s->ports);
 
diff --git a/hw/ide/cmd646.c b/hw/ide/cmd646.c
index a73eb9a..f6c222a 100644
--- a/hw/ide/cmd646.c
+++ b/hw/ide/cmd646.c
@@ -117,8 +117,8 @@ static void setup_cmd646_bar(PCIIDEState *d, int bus_num)
 
     bar->bus = bus;
     bar->pci_dev = d;
-    memory_region_init_io(&bar->cmd, &cmd646_cmd_ops, bar, "cmd646-cmd", 4);
-    memory_region_init_io(&bar->data, &cmd646_data_ops, bar, "cmd646-data", 8);
+    memory_region_init_io(&bar->cmd, NULL, &cmd646_cmd_ops, bar, "cmd646-cmd", 4);
+    memory_region_init_io(&bar->data, NULL, &cmd646_data_ops, bar, "cmd646-data", 8);
 }
 
 static uint64_t bmdma_read(void *opaque, hwaddr addr,
@@ -203,13 +203,13 @@ static void bmdma_setup_bar(PCIIDEState *d)
     BMDMAState *bm;
     int i;
 
-    memory_region_init(&d->bmdma_bar, "cmd646-bmdma", 16);
+    memory_region_init(&d->bmdma_bar, NULL, "cmd646-bmdma", 16);
     for(i = 0;i < 2; i++) {
         bm = &d->bmdma[i];
-        memory_region_init_io(&bm->extra_io, &cmd646_bmdma_ops, bm,
+        memory_region_init_io(&bm->extra_io, NULL, &cmd646_bmdma_ops, bm,
                               "cmd646-bmdma-bus", 4);
         memory_region_add_subregion(&d->bmdma_bar, i * 8, &bm->extra_io);
-        memory_region_init_io(&bm->addr_ioport, &bmdma_addr_ioport_ops, bm,
+        memory_region_init_io(&bm->addr_ioport, NULL, &bmdma_addr_ioport_ops, bm,
                               "cmd646-bmdma-ioport", 4);
         memory_region_add_subregion(&d->bmdma_bar, i * 8 + 4, &bm->addr_ioport);
     }
diff --git a/hw/ide/macio.c b/hw/ide/macio.c
index 84288ae..0c14009 100644
--- a/hw/ide/macio.c
+++ b/hw/ide/macio.c
@@ -335,7 +335,7 @@ static void macio_ide_initfn(Object *obj)
     MACIOIDEState *s = MACIO_IDE(obj);
 
     ide_bus_new(&s->bus, DEVICE(obj), 0, 2);
-    memory_region_init_io(&s->mem, &pmac_ide_ops, s, "pmac-ide", 0x1000);
+    memory_region_init_io(&s->mem, NULL, &pmac_ide_ops, s, "pmac-ide", 0x1000);
     sysbus_init_mmio(d, &s->mem);
     sysbus_init_irq(d, &s->irq);
     sysbus_init_irq(d, &s->dma_irq);
diff --git a/hw/ide/mmio.c b/hw/ide/mmio.c
index e80e7e5..8ae57d6 100644
--- a/hw/ide/mmio.c
+++ b/hw/ide/mmio.c
@@ -124,9 +124,9 @@ static void mmio_ide_realizefn(DeviceState *dev, Error **errp)
 
     ide_init2(&s->bus, s->irq);
 
-    memory_region_init_io(&s->iomem1, &mmio_ide_ops, s,
+    memory_region_init_io(&s->iomem1, NULL, &mmio_ide_ops, s,
                           "ide-mmio.1", 16 << s->shift);
-    memory_region_init_io(&s->iomem2, &mmio_ide_cs_ops, s,
+    memory_region_init_io(&s->iomem2, NULL, &mmio_ide_cs_ops, s,
                           "ide-mmio.2", 2 << s->shift);
     sysbus_init_mmio(d, &s->iomem1);
     sysbus_init_mmio(d, &s->iomem2);
diff --git a/hw/ide/piix.c b/hw/ide/piix.c
index bf2856f..af445db 100644
--- a/hw/ide/piix.c
+++ b/hw/ide/piix.c
@@ -90,14 +90,14 @@ static void bmdma_setup_bar(PCIIDEState *d)
 {
     int i;
 
-    memory_region_init(&d->bmdma_bar, "piix-bmdma-container", 16);
+    memory_region_init(&d->bmdma_bar, NULL, "piix-bmdma-container", 16);
     for(i = 0;i < 2; i++) {
         BMDMAState *bm = &d->bmdma[i];
 
-        memory_region_init_io(&bm->extra_io, &piix_bmdma_ops, bm,
+        memory_region_init_io(&bm->extra_io, NULL, &piix_bmdma_ops, bm,
                               "piix-bmdma", 4);
         memory_region_add_subregion(&d->bmdma_bar, i * 8, &bm->extra_io);
-        memory_region_init_io(&bm->addr_ioport, &bmdma_addr_ioport_ops, bm,
+        memory_region_init_io(&bm->addr_ioport, NULL, &bmdma_addr_ioport_ops, bm,
                               "bmdma", 4);
         memory_region_add_subregion(&d->bmdma_bar, i * 8 + 4, &bm->addr_ioport);
     }
diff --git a/hw/ide/via.c b/hw/ide/via.c
index 5fe053c..1691717 100644
--- a/hw/ide/via.c
+++ b/hw/ide/via.c
@@ -92,14 +92,14 @@ static void bmdma_setup_bar(PCIIDEState *d)
 {
     int i;
 
-    memory_region_init(&d->bmdma_bar, "via-bmdma-container", 16);
+    memory_region_init(&d->bmdma_bar, NULL, "via-bmdma-container", 16);
     for(i = 0;i < 2; i++) {
         BMDMAState *bm = &d->bmdma[i];
 
-        memory_region_init_io(&bm->extra_io, &via_bmdma_ops, bm,
+        memory_region_init_io(&bm->extra_io, NULL, &via_bmdma_ops, bm,
                               "via-bmdma", 4);
         memory_region_add_subregion(&d->bmdma_bar, i * 8, &bm->extra_io);
-        memory_region_init_io(&bm->addr_ioport, &bmdma_addr_ioport_ops, bm,
+        memory_region_init_io(&bm->addr_ioport, NULL, &bmdma_addr_ioport_ops, bm,
                               "bmdma", 4);
         memory_region_add_subregion(&d->bmdma_bar, i * 8 + 4, &bm->addr_ioport);
     }
diff --git a/hw/input/milkymist-softusb.c b/hw/input/milkymist-softusb.c
index 3edab4f..69e6485 100644
--- a/hw/input/milkymist-softusb.c
+++ b/hw/input/milkymist-softusb.c
@@ -265,17 +265,17 @@ static int milkymist_softusb_init(SysBusDevice *dev)
 
     sysbus_init_irq(dev, &s->irq);
 
-    memory_region_init_io(&s->regs_region, &softusb_mmio_ops, s,
+    memory_region_init_io(&s->regs_region, NULL, &softusb_mmio_ops, s,
                           "milkymist-softusb", R_MAX * 4);
     sysbus_init_mmio(dev, &s->regs_region);
 
     /* register pmem and dmem */
-    memory_region_init_ram(&s->pmem, "milkymist-softusb.pmem",
+    memory_region_init_ram(&s->pmem, NULL, "milkymist-softusb.pmem",
                            s->pmem_size);
     vmstate_register_ram_global(&s->pmem);
     s->pmem_ptr = memory_region_get_ram_ptr(&s->pmem);
     sysbus_init_mmio(dev, &s->pmem);
-    memory_region_init_ram(&s->dmem, "milkymist-softusb.dmem",
+    memory_region_init_ram(&s->dmem, NULL, "milkymist-softusb.dmem",
                            s->dmem_size);
     vmstate_register_ram_global(&s->dmem);
     s->dmem_ptr = memory_region_get_ram_ptr(&s->dmem);
diff --git a/hw/input/pckbd.c b/hw/input/pckbd.c
index fff0a4d..8d1d6a7 100644
--- a/hw/input/pckbd.c
+++ b/hw/input/pckbd.c
@@ -424,7 +424,7 @@ void i8042_mm_init(qemu_irq kbd_irq, qemu_irq mouse_irq,
 
     vmstate_register(NULL, 0, &vmstate_kbd, s);
 
-    memory_region_init_io(region, &i8042_mmio_ops, s, "i8042", size);
+    memory_region_init_io(region, NULL, &i8042_mmio_ops, s, "i8042", size);
 
     s->kbd = ps2_kbd_init(kbd_update_kbd_irq, s);
     s->mouse = ps2_mouse_init(kbd_update_aux_irq, s);
@@ -494,8 +494,8 @@ static void i8042_initfn(Object *obj)
     ISAKBDState *isa_s = I8042(obj);
     KBDState *s = &isa_s->kbd;
 
-    memory_region_init_io(isa_s->io + 0, &i8042_data_ops, s, "i8042-data", 1);
-    memory_region_init_io(isa_s->io + 1, &i8042_cmd_ops, s, "i8042-cmd", 1);
+    memory_region_init_io(isa_s->io + 0, NULL, &i8042_data_ops, s, "i8042-data", 1);
+    memory_region_init_io(isa_s->io + 1, NULL, &i8042_cmd_ops, s, "i8042-cmd", 1);
 }
 
 static void i8042_realizefn(DeviceState *dev, Error **errp)
diff --git a/hw/input/pl050.c b/hw/input/pl050.c
index 7dd8a59..871ffba 100644
--- a/hw/input/pl050.c
+++ b/hw/input/pl050.c
@@ -137,7 +137,7 @@ static int pl050_init(SysBusDevice *dev, int is_mouse)
 {
     pl050_state *s = FROM_SYSBUS(pl050_state, dev);
 
-    memory_region_init_io(&s->iomem, &pl050_ops, s, "pl050", 0x1000);
+    memory_region_init_io(&s->iomem, NULL, &pl050_ops, s, "pl050", 0x1000);
     sysbus_init_mmio(dev, &s->iomem);
     sysbus_init_irq(dev, &s->irq);
     s->is_mouse = is_mouse;
diff --git a/hw/input/pxa2xx_keypad.c b/hw/input/pxa2xx_keypad.c
index 1fd5f20..846d137 100644
--- a/hw/input/pxa2xx_keypad.c
+++ b/hw/input/pxa2xx_keypad.c
@@ -313,7 +313,7 @@ PXA2xxKeyPadState *pxa27x_keypad_init(MemoryRegion *sysmem,
     s = (PXA2xxKeyPadState *) g_malloc0(sizeof(PXA2xxKeyPadState));
     s->irq = irq;
 
-    memory_region_init_io(&s->iomem, &pxa2xx_keypad_ops, s,
+    memory_region_init_io(&s->iomem, NULL, &pxa2xx_keypad_ops, s,
                           "pxa2xx-keypad", 0x00100000);
     memory_region_add_subregion(sysmem, base, &s->iomem);
 
diff --git a/hw/intc/apic.c b/hw/intc/apic.c
index 46cb097..d15c8be 100644
--- a/hw/intc/apic.c
+++ b/hw/intc/apic.c
@@ -873,7 +873,7 @@ static const MemoryRegionOps apic_io_ops = {
 
 static void apic_init(APICCommonState *s)
 {
-    memory_region_init_io(&s->io_memory, &apic_io_ops, s, "apic-msi",
+    memory_region_init_io(&s->io_memory, NULL, &apic_io_ops, s, "apic-msi",
                           APIC_SPACE_SIZE);
 
     s->timer = qemu_new_timer_ns(vm_clock, apic_timer, s);
diff --git a/hw/intc/arm_gic.c b/hw/intc/arm_gic.c
index bae6572..a5ff762 100644
--- a/hw/intc/arm_gic.c
+++ b/hw/intc/arm_gic.c
@@ -656,7 +656,7 @@ void gic_init_irqs_and_distributor(GICState *s, int num_irq)
     for (i = 0; i < NUM_CPU(s); i++) {
         sysbus_init_irq(&s->busdev, &s->parent_irq[i]);
     }
-    memory_region_init_io(&s->iomem, &gic_dist_ops, s, "gic_dist", 0x1000);
+    memory_region_init_io(&s->iomem, NULL, &gic_dist_ops, s, "gic_dist", 0x1000);
 }
 
 static void arm_gic_realize(DeviceState *dev, Error **errp)
@@ -682,11 +682,11 @@ static void arm_gic_realize(DeviceState *dev, Error **errp)
      * GIC v2 defines a larger memory region (0x1000) so this will need
      * to be extended when we implement A15.
      */
-    memory_region_init_io(&s->cpuiomem[0], &gic_thiscpu_ops, s,
+    memory_region_init_io(&s->cpuiomem[0], NULL, &gic_thiscpu_ops, s,
                           "gic_cpu", 0x100);
     for (i = 0; i < NUM_CPU(s); i++) {
         s->backref[i] = s;
-        memory_region_init_io(&s->cpuiomem[i+1], &gic_cpu_ops, &s->backref[i],
+        memory_region_init_io(&s->cpuiomem[i+1], NULL, &gic_cpu_ops, &s->backref[i],
                               "gic_cpu", 0x100);
     }
     /* Distributor */
diff --git a/hw/intc/arm_gic_kvm.c b/hw/intc/arm_gic_kvm.c
index b756456..687d1e2 100644
--- a/hw/intc/arm_gic_kvm.c
+++ b/hw/intc/arm_gic_kvm.c
@@ -120,7 +120,7 @@ static void kvm_arm_gic_realize(DeviceState *dev, Error **errp)
         sysbus_init_irq(sbd, &s->parent_irq[i]);
     }
     /* Distributor */
-    memory_region_init_reservation(&s->iomem, "kvm-gic_dist", 0x1000);
+    memory_region_init_reservation(&s->iomem, NULL, "kvm-gic_dist", 0x1000);
     sysbus_init_mmio(sbd, &s->iomem);
     kvm_arm_register_device(&s->iomem,
                             (KVM_ARM_DEVICE_VGIC_V2 << KVM_ARM_DEVICE_ID_SHIFT)
@@ -129,7 +129,7 @@ static void kvm_arm_gic_realize(DeviceState *dev, Error **errp)
      * provide the "interface for core #N" memory regions, because
      * cores with a VGIC don't have those.
      */
-    memory_region_init_reservation(&s->cpuiomem[0], "kvm-gic_cpu", 0x1000);
+    memory_region_init_reservation(&s->cpuiomem[0], NULL, "kvm-gic_cpu", 0x1000);
     sysbus_init_mmio(sbd, &s->cpuiomem[0]);
     kvm_arm_register_device(&s->cpuiomem[0],
                             (KVM_ARM_DEVICE_VGIC_V2 << KVM_ARM_DEVICE_ID_SHIFT)
diff --git a/hw/intc/armv7m_nvic.c b/hw/intc/armv7m_nvic.c
index 25fa43c..74baa72 100644
--- a/hw/intc/armv7m_nvic.c
+++ b/hw/intc/armv7m_nvic.c
@@ -487,17 +487,17 @@ static void armv7m_nvic_realize(DeviceState *dev, Error **errp)
      * We use overlaying to put the GIC like registers
      * over the top of the system control register region.
      */
-    memory_region_init(&s->container, "nvic", 0x1000);
+    memory_region_init(&s->container, NULL, "nvic", 0x1000);
     /* The system register region goes at the bottom of the priority
      * stack as it covers the whole page.
      */
-    memory_region_init_io(&s->sysregmem, &nvic_sysreg_ops, s,
+    memory_region_init_io(&s->sysregmem, NULL, &nvic_sysreg_ops, s,
                           "nvic_sysregs", 0x1000);
     memory_region_add_subregion(&s->container, 0, &s->sysregmem);
     /* Alias the GIC region so we can get only the section of it
      * we need, and layer it on top of the system register region.
      */
-    memory_region_init_alias(&s->gic_iomem_alias, "nvic-gic", &s->gic.iomem,
+    memory_region_init_alias(&s->gic_iomem_alias, NULL, "nvic-gic", &s->gic.iomem,
                              0x100, 0xc00);
     memory_region_add_subregion_overlap(&s->container, 0x100,
                                         &s->gic_iomem_alias, 1);
diff --git a/hw/intc/etraxfs_pic.c b/hw/intc/etraxfs_pic.c
index 635103c..81e1ab9 100644
--- a/hw/intc/etraxfs_pic.c
+++ b/hw/intc/etraxfs_pic.c
@@ -146,7 +146,7 @@ static int etraxfs_pic_init(SysBusDevice *dev)
     sysbus_init_irq(dev, &s->parent_irq);
     sysbus_init_irq(dev, &s->parent_nmi);
 
-    memory_region_init_io(&s->mmio, &pic_ops, s, "etraxfs-pic", R_MAX * 4);
+    memory_region_init_io(&s->mmio, NULL, &pic_ops, s, "etraxfs-pic", R_MAX * 4);
     sysbus_init_mmio(dev, &s->mmio);
     return 0;
 }
diff --git a/hw/intc/exynos4210_combiner.c b/hw/intc/exynos4210_combiner.c
index 6874287..644d6b3 100644
--- a/hw/intc/exynos4210_combiner.c
+++ b/hw/intc/exynos4210_combiner.c
@@ -417,7 +417,7 @@ static int exynos4210_combiner_init(SysBusDevice *dev)
         sysbus_init_irq(dev, &s->output_irq[i]);
     }
 
-    memory_region_init_io(&s->iomem, &exynos4210_combiner_ops, s,
+    memory_region_init_io(&s->iomem, NULL, &exynos4210_combiner_ops, s,
             "exynos4210-combiner", IIC_REGION_SIZE);
     sysbus_init_mmio(dev, &s->iomem);
 
diff --git a/hw/intc/exynos4210_gic.c b/hw/intc/exynos4210_gic.c
index bad6dde..f9c4218 100644
--- a/hw/intc/exynos4210_gic.c
+++ b/hw/intc/exynos4210_gic.c
@@ -299,15 +299,15 @@ static int exynos4210_gic_init(SysBusDevice *dev)
     qdev_init_gpio_in(&s->busdev.qdev, exynos4210_gic_set_irq,
                       EXYNOS4210_GIC_NIRQ - 32);
 
-    memory_region_init(&s->cpu_container, "exynos4210-cpu-container",
+    memory_region_init(&s->cpu_container, NULL, "exynos4210-cpu-container",
             EXYNOS4210_EXT_GIC_CPU_REGION_SIZE);
-    memory_region_init(&s->dist_container, "exynos4210-dist-container",
+    memory_region_init(&s->dist_container, NULL, "exynos4210-dist-container",
             EXYNOS4210_EXT_GIC_DIST_REGION_SIZE);
 
     for (i = 0; i < s->num_cpu; i++) {
         /* Map CPU interface per SMP Core */
         sprintf(cpu_alias_name, "%s%x", cpu_prefix, i);
-        memory_region_init_alias(&s->cpu_alias[i],
+        memory_region_init_alias(&s->cpu_alias[i], NULL,
                                  cpu_alias_name,
                                  sysbus_mmio_get_region(busdev, 1),
                                  0,
@@ -317,7 +317,7 @@ static int exynos4210_gic_init(SysBusDevice *dev)
 
         /* Map Distributor per SMP Core */
         sprintf(dist_alias_name, "%s%x", dist_prefix, i);
-        memory_region_init_alias(&s->dist_alias[i],
+        memory_region_init_alias(&s->dist_alias[i], NULL,
                                  dist_alias_name,
                                  sysbus_mmio_get_region(busdev, 0),
                                  0,
diff --git a/hw/intc/grlib_irqmp.c b/hw/intc/grlib_irqmp.c
index 68dfe6a..f933e6a 100644
--- a/hw/intc/grlib_irqmp.c
+++ b/hw/intc/grlib_irqmp.c
@@ -344,7 +344,7 @@ static int grlib_irqmp_init(SysBusDevice *dev)
         return -1;
     }
 
-    memory_region_init_io(&irqmp->iomem, &grlib_irqmp_ops, irqmp,
+    memory_region_init_io(&irqmp->iomem, NULL, &grlib_irqmp_ops, irqmp,
                           "irqmp", IRQMP_REG_SIZE);
 
     irqmp->state = g_malloc0(sizeof *irqmp->state);
diff --git a/hw/intc/heathrow_pic.c b/hw/intc/heathrow_pic.c
index beb9661..9818f24 100644
--- a/hw/intc/heathrow_pic.c
+++ b/hw/intc/heathrow_pic.c
@@ -205,7 +205,7 @@ qemu_irq *heathrow_pic_init(MemoryRegion **pmem,
     s = g_malloc0(sizeof(HeathrowPICS));
     /* only 1 CPU */
     s->irqs = irqs[0];
-    memory_region_init_io(&s->mem, &heathrow_pic_ops, s,
+    memory_region_init_io(&s->mem, NULL, &heathrow_pic_ops, s,
                           "heathrow-pic", 0x1000);
     *pmem = &s->mem;
 
diff --git a/hw/intc/i8259.c b/hw/intc/i8259.c
index 192a0ba..13250f1 100644
--- a/hw/intc/i8259.c
+++ b/hw/intc/i8259.c
@@ -417,8 +417,8 @@ static void pic_realize(DeviceState *dev, Error **err)
     PICCommonState *s = PIC_COMMON(dev);
     PICClass *pc = PIC_GET_CLASS(dev);
 
-    memory_region_init_io(&s->base_io, &pic_base_ioport_ops, s, "pic", 2);
-    memory_region_init_io(&s->elcr_io, &pic_elcr_ioport_ops, s, "elcr", 1);
+    memory_region_init_io(&s->base_io, NULL, &pic_base_ioport_ops, s, "pic", 2);
+    memory_region_init_io(&s->elcr_io, NULL, &pic_elcr_ioport_ops, s, "elcr", 1);
 
     qdev_init_gpio_out(dev, s->int_out, ARRAY_SIZE(s->int_out));
     qdev_init_gpio_in(dev, pic_set_irq, 8);
diff --git a/hw/intc/imx_avic.c b/hw/intc/imx_avic.c
index ff45dcd..870d56f 100644
--- a/hw/intc/imx_avic.c
+++ b/hw/intc/imx_avic.c
@@ -372,7 +372,7 @@ static int imx_avic_init(SysBusDevice *dev)
 {
     IMXAVICState *s = FROM_SYSBUS(IMXAVICState, dev);
 
-    memory_region_init_io(&s->iomem, &imx_avic_ops, s, "imx_avic", 0x1000);
+    memory_region_init_io(&s->iomem, NULL, &imx_avic_ops, s, "imx_avic", 0x1000);
     sysbus_init_mmio(dev, &s->iomem);
 
     qdev_init_gpio_in(&dev->qdev, imx_avic_set_irq, IMX_AVIC_NUM_IRQS);
diff --git a/hw/intc/ioapic.c b/hw/intc/ioapic.c
index c6f09f4..7299b50 100644
--- a/hw/intc/ioapic.c
+++ b/hw/intc/ioapic.c
@@ -227,7 +227,7 @@ static const MemoryRegionOps ioapic_io_ops = {
 
 static void ioapic_init(IOAPICCommonState *s, int instance_no)
 {
-    memory_region_init_io(&s->io_memory, &ioapic_io_ops, s, "ioapic", 0x1000);
+    memory_region_init_io(&s->io_memory, NULL, &ioapic_io_ops, s, "ioapic", 0x1000);
 
     qdev_init_gpio_in(&s->busdev.qdev, ioapic_set_irq, IOAPIC_NUM_PINS);
 
diff --git a/hw/intc/omap_intc.c b/hw/intc/omap_intc.c
index 875eba4..00cb6ca 100644
--- a/hw/intc/omap_intc.c
+++ b/hw/intc/omap_intc.c
@@ -367,7 +367,7 @@ static int omap_intc_init(SysBusDevice *dev)
     sysbus_init_irq(dev, &s->parent_intr[0]);
     sysbus_init_irq(dev, &s->parent_intr[1]);
     qdev_init_gpio_in(&dev->qdev, omap_set_intr, s->nbanks * 32);
-    memory_region_init_io(&s->mmio, &omap_inth_mem_ops, s,
+    memory_region_init_io(&s->mmio, NULL, &omap_inth_mem_ops, s,
                           "omap-intc", s->size);
     sysbus_init_mmio(dev, &s->mmio);
     return 0;
@@ -609,7 +609,7 @@ static int omap2_intc_init(SysBusDevice *dev)
     sysbus_init_irq(dev, &s->parent_intr[0]);
     sysbus_init_irq(dev, &s->parent_intr[1]);
     qdev_init_gpio_in(&dev->qdev, omap_set_intr_noedge, s->nbanks * 32);
-    memory_region_init_io(&s->mmio, &omap2_inth_mem_ops, s,
+    memory_region_init_io(&s->mmio, NULL, &omap2_inth_mem_ops, s,
                           "omap2-intc", 0x1000);
     sysbus_init_mmio(dev, &s->mmio);
     return 0;
diff --git a/hw/intc/openpic.c b/hw/intc/openpic.c
index c788714..5777ece 100644
--- a/hw/intc/openpic.c
+++ b/hw/intc/openpic.c
@@ -1515,7 +1515,7 @@ static void map_list(OpenPICState *opp, const MemReg *list, int *count)
     while (list->name) {
         assert(*count < ARRAY_SIZE(opp->sub_io_mem));
 
-        memory_region_init_io(&opp->sub_io_mem[*count], list->ops, opp,
+        memory_region_init_io(&opp->sub_io_mem[*count], NULL, list->ops, opp,
                               list->name, list->size);
 
         memory_region_add_subregion(&opp->mem, list->start_addr,
@@ -1561,7 +1561,7 @@ static int openpic_init(SysBusDevice *dev)
         {NULL}
     };
 
-    memory_region_init(&opp->mem, "openpic", 0x40000);
+    memory_region_init(&opp->mem, NULL, "openpic", 0x40000);
 
     switch (opp->model) {
     case OPENPIC_MODEL_FSL_MPIC_20:
diff --git a/hw/intc/pl190.c b/hw/intc/pl190.c
index 9610673..5f0f9b7 100644
--- a/hw/intc/pl190.c
+++ b/hw/intc/pl190.c
@@ -236,7 +236,7 @@ static int pl190_init(SysBusDevice *dev)
 {
     pl190_state *s = FROM_SYSBUS(pl190_state, dev);
 
-    memory_region_init_io(&s->iomem, &pl190_ops, s, "pl190", 0x1000);
+    memory_region_init_io(&s->iomem, NULL, &pl190_ops, s, "pl190", 0x1000);
     sysbus_init_mmio(dev, &s->iomem);
     qdev_init_gpio_in(&dev->qdev, pl190_set_irq, 32);
     sysbus_init_irq(dev, &s->irq);
diff --git a/hw/intc/puv3_intc.c b/hw/intc/puv3_intc.c
index 0cd5e9e..b327f0e 100644
--- a/hw/intc/puv3_intc.c
+++ b/hw/intc/puv3_intc.c
@@ -106,7 +106,7 @@ static int puv3_intc_init(SysBusDevice *dev)
     s->reg_ICMR = 0;
     s->reg_ICPR = 0;
 
-    memory_region_init_io(&s->iomem, &puv3_intc_ops, s, "puv3_intc",
+    memory_region_init_io(&s->iomem, NULL, &puv3_intc_ops, s, "puv3_intc",
             PUV3_REGS_OFFSET);
     sysbus_init_mmio(dev, &s->iomem);
 
diff --git a/hw/intc/realview_gic.c b/hw/intc/realview_gic.c
index 0ec30ca..1731a70 100644
--- a/hw/intc/realview_gic.c
+++ b/hw/intc/realview_gic.c
@@ -43,7 +43,7 @@ static int realview_gic_init(SysBusDevice *dev)
     /* Pass through inbound GPIO lines to the GIC */
     qdev_init_gpio_in(&s->busdev.qdev, realview_gic_set_irq, numirq - 32);
 
-    memory_region_init(&s->container, "realview-gic-container", 0x2000);
+    memory_region_init(&s->container, NULL, "realview-gic-container", 0x2000);
     memory_region_add_subregion(&s->container, 0,
                                 sysbus_mmio_get_region(busdev, 1));
     memory_region_add_subregion(&s->container, 0x1000,
diff --git a/hw/intc/sh_intc.c b/hw/intc/sh_intc.c
index 050bfb6..f397950 100644
--- a/hw/intc/sh_intc.c
+++ b/hw/intc/sh_intc.c
@@ -319,11 +319,11 @@ static unsigned int sh_intc_register(MemoryRegion *sysmem,
 
 #define SH_INTC_IOMEM_FORMAT "interrupt-controller-%s-%s-%s"
     snprintf(name, sizeof(name), SH_INTC_IOMEM_FORMAT, type, action, "p4");
-    memory_region_init_alias(iomem_p4, name, iomem, INTC_A7(address), 4);
+    memory_region_init_alias(iomem_p4, NULL, name, iomem, INTC_A7(address), 4);
     memory_region_add_subregion(sysmem, P4ADDR(address), iomem_p4);
 
     snprintf(name, sizeof(name), SH_INTC_IOMEM_FORMAT, type, action, "a7");
-    memory_region_init_alias(iomem_a7, name, iomem, INTC_A7(address), 4);
+    memory_region_init_alias(iomem_a7, NULL, name, iomem, INTC_A7(address), 4);
     memory_region_add_subregion(sysmem, A7ADDR(address), iomem_a7);
 #undef SH_INTC_IOMEM_FORMAT
 
@@ -466,7 +466,7 @@ int sh_intc_init(MemoryRegion *sysmem,
 
     desc->irqs = qemu_allocate_irqs(sh_intc_set_irq, desc, nr_sources);
  
-    memory_region_init_io(&desc->iomem, &sh_intc_ops, desc,
+    memory_region_init_io(&desc->iomem, NULL, &sh_intc_ops, desc,
                           "interrupt-controller", 0x100000000ULL);
 
 #define INT_REG_PARAMS(reg_struct, type, action, j) \
diff --git a/hw/intc/slavio_intctl.c b/hw/intc/slavio_intctl.c
index b367752..716e36d 100644
--- a/hw/intc/slavio_intctl.c
+++ b/hw/intc/slavio_intctl.c
@@ -426,7 +426,7 @@ static int slavio_intctl_init1(SysBusDevice *dev)
     char slave_name[45];
 
     qdev_init_gpio_in(&dev->qdev, slavio_set_irq_all, 32 + MAX_CPUS);
-    memory_region_init_io(&s->iomem, &slavio_intctlm_mem_ops, s,
+    memory_region_init_io(&s->iomem, NULL, &slavio_intctlm_mem_ops, s,
                           "master-interrupt-controller", INTCTLM_SIZE);
     sysbus_init_mmio(dev, &s->iomem);
 
@@ -436,7 +436,7 @@ static int slavio_intctl_init1(SysBusDevice *dev)
         for (j = 0; j < MAX_PILS; j++) {
             sysbus_init_irq(dev, &s->cpu_irqs[i][j]);
         }
-        memory_region_init_io(&s->slaves[i].iomem, &slavio_intctl_mem_ops,
+        memory_region_init_io(&s->slaves[i].iomem, NULL, &slavio_intctl_mem_ops,
                               &s->slaves[i], slave_name, INTCTL_SIZE);
         sysbus_init_mmio(dev, &s->slaves[i].iomem);
         s->slaves[i].cpu = i;
diff --git a/hw/intc/xilinx_intc.c b/hw/intc/xilinx_intc.c
index 297f537..9ba35f6 100644
--- a/hw/intc/xilinx_intc.c
+++ b/hw/intc/xilinx_intc.c
@@ -160,7 +160,7 @@ static int xilinx_intc_init(SysBusDevice *dev)
     qdev_init_gpio_in(&dev->qdev, irq_handler, 32);
     sysbus_init_irq(dev, &p->parent_irq);
 
-    memory_region_init_io(&p->mmio, &pic_ops, p, "xlnx.xps-intc", R_MAX * 4);
+    memory_region_init_io(&p->mmio, NULL, &pic_ops, p, "xlnx.xps-intc", R_MAX * 4);
     sysbus_init_mmio(dev, &p->mmio);
     return 0;
 }
diff --git a/hw/isa/apm.c b/hw/isa/apm.c
index 5f21d21..daed6f1 100644
--- a/hw/isa/apm.c
+++ b/hw/isa/apm.c
@@ -96,7 +96,7 @@ void apm_init(PCIDevice *dev, APMState *apm, apm_ctrl_changed_t callback,
     apm->arg = arg;
 
     /* ioport 0xb2, 0xb3 */
-    memory_region_init_io(&apm->io, &apm_ops, apm, "apm-io", 2);
+    memory_region_init_io(&apm->io, NULL, &apm_ops, apm, "apm-io", 2);
     memory_region_add_subregion(pci_address_space_io(dev), APM_CNT_IOPORT,
                                 &apm->io);
 }
diff --git a/hw/isa/i82378.c b/hw/isa/i82378.c
index a24cb98..90f36d5 100644
--- a/hw/isa/i82378.c
+++ b/hw/isa/i82378.c
@@ -221,10 +221,10 @@ static int pci_i82378_init(PCIDevice *dev)
 
     pci_conf[PCI_INTERRUPT_PIN] = 1; /* interrupt pin 0 */
 
-    memory_region_init_io(&s->io, &i82378_io_ops, s, "i82378-io", 0x00010000);
+    memory_region_init_io(&s->io, NULL, &i82378_io_ops, s, "i82378-io", 0x00010000);
     pci_register_bar(dev, 0, PCI_BASE_ADDRESS_SPACE_MEMORY, &s->io);
 
-    memory_region_init_io(&s->mem, &i82378_mem_ops, s, "i82378-mem", 0x01000000);
+    memory_region_init_io(&s->mem, NULL, &i82378_mem_ops, s, "i82378-mem", 0x01000000);
     pci_register_bar(dev, 1, PCI_BASE_ADDRESS_SPACE_MEMORY, &s->mem);
 
     /* Make I/O address read only */
diff --git a/hw/isa/isa_mmio.c b/hw/isa/isa_mmio.c
index d4dbf13..00ae8eb 100644
--- a/hw/isa/isa_mmio.c
+++ b/hw/isa/isa_mmio.c
@@ -69,7 +69,7 @@ static const MemoryRegionOps isa_mmio_ops = {
 
 void isa_mmio_setup(MemoryRegion *mr, hwaddr size)
 {
-    memory_region_init_io(mr, &isa_mmio_ops, NULL, "isa-mmio", size);
+    memory_region_init_io(mr, NULL, &isa_mmio_ops, NULL, "isa-mmio", size);
 }
 
 void isa_mmio_init(hwaddr base, hwaddr size)
diff --git a/hw/isa/lpc_ich9.c b/hw/isa/lpc_ich9.c
index 461ab7c..82f8ea6 100644
--- a/hw/isa/lpc_ich9.c
+++ b/hw/isa/lpc_ich9.c
@@ -535,7 +535,7 @@ static int ich9_lpc_initfn(PCIDevice *d)
     pci_set_long(d->wmask + ICH9_LPC_PMBASE,
                  ICH9_LPC_PMBASE_BASE_ADDRESS_MASK);
 
-    memory_region_init_io(&lpc->rbca_mem, &rbca_mmio_ops, lpc,
+    memory_region_init_io(&lpc->rbca_mem, NULL, &rbca_mmio_ops, lpc,
                             "lpc-rbca-mmio", ICH9_CC_SIZE);
 
     lpc->isa_bus = isa_bus;
@@ -546,7 +546,7 @@ static int ich9_lpc_initfn(PCIDevice *d)
     lpc->machine_ready.notify = ich9_lpc_machine_ready;
     qemu_add_machine_init_done_notifier(&lpc->machine_ready);
 
-    memory_region_init_io(&lpc->rst_cnt_mem, &ich9_rst_cnt_ops, lpc,
+    memory_region_init_io(&lpc->rst_cnt_mem, NULL, &ich9_rst_cnt_ops, lpc,
                           "lpc-reset-control", 1);
     memory_region_add_subregion_overlap(pci_address_space_io(d),
                                         ICH9_RST_CNT_IOPORT, &lpc->rst_cnt_mem,
diff --git a/hw/isa/pc87312.c b/hw/isa/pc87312.c
index cc426df..7b3e7fb 100644
--- a/hw/isa/pc87312.c
+++ b/hw/isa/pc87312.c
@@ -352,7 +352,7 @@ static void pc87312_initfn(Object *obj)
 {
     PC87312State *s = PC87312(obj);
 
-    memory_region_init_io(&s->io, &pc87312_io_ops, s, "pc87312", 2);
+    memory_region_init_io(&s->io, NULL, &pc87312_io_ops, s, "pc87312", 2);
 }
 
 static const VMStateDescription vmstate_pc87312 = {
diff --git a/hw/isa/vt82c686.c b/hw/isa/vt82c686.c
index e5cd4cd..1f63197 100644
--- a/hw/isa/vt82c686.c
+++ b/hw/isa/vt82c686.c
@@ -356,7 +356,7 @@ static int vt82c686b_pm_initfn(PCIDevice *dev)
 
     apm_init(dev, &s->apm, NULL, s);
 
-    memory_region_init(&s->io, "vt82c686-pm", 64);
+    memory_region_init(&s->io, NULL, "vt82c686-pm", 64);
     memory_region_set_enabled(&s->io, false);
     memory_region_add_subregion(get_system_io(), 0, &s->io);
 
@@ -443,8 +443,8 @@ static int vt82c686b_initfn(PCIDevice *d)
        }
     }
 
-    memory_region_init_io(&vt82c->superio, &superio_ops, &vt82c->superio_conf,
-                          "superio", 2);
+    memory_region_init_io(&vt82c->superio, NULL, &superio_ops,
+                          &vt82c->superio_conf, "superio", 2);
     memory_region_set_enabled(&vt82c->superio, false);
     /* The floppy also uses 0x3f0 and 0x3f1.
      * But we do not emulate a floppy, so just set it here. */
diff --git a/hw/lm32/lm32_boards.c b/hw/lm32/lm32_boards.c
index 1ca9498..62003b8 100644
--- a/hw/lm32/lm32_boards.c
+++ b/hw/lm32/lm32_boards.c
@@ -106,7 +106,7 @@ static void lm32_evr_init(QEMUMachineInitArgs *args)
 
     reset_info->flash_base = flash_base;
 
-    memory_region_init_ram(phys_ram, "lm32_evr.sdram", ram_size);
+    memory_region_init_ram(phys_ram, NULL, "lm32_evr.sdram", ram_size);
     vmstate_register_ram_global(phys_ram);
     memory_region_add_subregion(address_space_mem, ram_base, phys_ram);
 
@@ -203,7 +203,7 @@ static void lm32_uclinux_init(QEMUMachineInitArgs *args)
 
     reset_info->flash_base = flash_base;
 
-    memory_region_init_ram(phys_ram, "lm32_uclinux.sdram", ram_size);
+    memory_region_init_ram(phys_ram, NULL, "lm32_uclinux.sdram", ram_size);
     vmstate_register_ram_global(phys_ram);
     memory_region_add_subregion(address_space_mem, ram_base, phys_ram);
 
diff --git a/hw/lm32/milkymist.c b/hw/lm32/milkymist.c
index cca9374..7ceedb8 100644
--- a/hw/lm32/milkymist.c
+++ b/hw/lm32/milkymist.c
@@ -112,7 +112,7 @@ milkymist_init(QEMUMachineInitArgs *args)
 
     cpu_lm32_set_phys_msb_ignore(env, 1);
 
-    memory_region_init_ram(phys_sdram, "milkymist.sdram", sdram_size);
+    memory_region_init_ram(phys_sdram, NULL, "milkymist.sdram", sdram_size);
     vmstate_register_ram_global(phys_sdram);
     memory_region_add_subregion(address_space_mem, sdram_base, phys_sdram);
 
diff --git a/hw/m68k/an5206.c b/hw/m68k/an5206.c
index c4a5626..0c03a87 100644
--- a/hw/m68k/an5206.c
+++ b/hw/m68k/an5206.c
@@ -49,12 +49,12 @@ static void an5206_init(QEMUMachineInitArgs *args)
     env->rambar0 = AN5206_RAMBAR_ADDR | 1;
 
     /* DRAM at address zero */
-    memory_region_init_ram(ram, "an5206.ram", ram_size);
+    memory_region_init_ram(ram, NULL, "an5206.ram", ram_size);
     vmstate_register_ram_global(ram);
     memory_region_add_subregion(address_space_mem, 0, ram);
 
     /* Internal SRAM.  */
-    memory_region_init_ram(sram, "an5206.sram", 512);
+    memory_region_init_ram(sram, NULL, "an5206.sram", 512);
     vmstate_register_ram_global(sram);
     memory_region_add_subregion(address_space_mem, AN5206_RAMBAR_ADDR, sram);
 
diff --git a/hw/m68k/dummy_m68k.c b/hw/m68k/dummy_m68k.c
index 544d56b..f4ed7c6 100644
--- a/hw/m68k/dummy_m68k.c
+++ b/hw/m68k/dummy_m68k.c
@@ -40,7 +40,7 @@ static void dummy_m68k_init(QEMUMachineInitArgs *args)
     env->vbr = 0;
 
     /* RAM at address zero */
-    memory_region_init_ram(ram, "dummy_m68k.ram", ram_size);
+    memory_region_init_ram(ram, NULL, "dummy_m68k.ram", ram_size);
     vmstate_register_ram_global(ram);
     memory_region_add_subregion(address_space_mem, 0, ram);
 
diff --git a/hw/m68k/mcf5206.c b/hw/m68k/mcf5206.c
index bcc619d..1727a46 100644
--- a/hw/m68k/mcf5206.c
+++ b/hw/m68k/mcf5206.c
@@ -532,7 +532,7 @@ qemu_irq *mcf5206_init(MemoryRegion *sysmem, uint32_t base, M68kCPU *cpu)
 
     s = (m5206_mbar_state *)g_malloc0(sizeof(m5206_mbar_state));
 
-    memory_region_init_io(&s->iomem, &m5206_mbar_ops, s,
+    memory_region_init_io(&s->iomem, NULL, &m5206_mbar_ops, s,
                           "mbar", 0x00001000);
     memory_region_add_subregion(sysmem, base, &s->iomem);
 
diff --git a/hw/m68k/mcf5208.c b/hw/m68k/mcf5208.c
index 05efde7..9cf000f 100644
--- a/hw/m68k/mcf5208.c
+++ b/hw/m68k/mcf5208.c
@@ -172,14 +172,14 @@ static void mcf5208_sys_init(MemoryRegion *address_space, qemu_irq *pic)
     int i;
 
     /* SDRAMC.  */
-    memory_region_init_io(iomem, &m5208_sys_ops, NULL, "m5208-sys", 0x00004000);
+    memory_region_init_io(iomem, NULL, &m5208_sys_ops, NULL, "m5208-sys", 0x00004000);
     memory_region_add_subregion(address_space, 0xfc0a8000, iomem);
     /* Timers.  */
     for (i = 0; i < 2; i++) {
         s = (m5208_timer_state *)g_malloc0(sizeof(m5208_timer_state));
         bh = qemu_bh_new(m5208_timer_trigger, s);
         s->timer = ptimer_init(bh);
-        memory_region_init_io(&s->iomem, &m5208_timer_ops, s,
+        memory_region_init_io(&s->iomem, NULL, &m5208_timer_ops, s,
                               "m5208-timer", 0x00004000);
         memory_region_add_subregion(address_space, 0xfc080000 + 0x4000 * i,
                                     &s->iomem);
@@ -217,12 +217,12 @@ static void mcf5208evb_init(QEMUMachineInitArgs *args)
     /* TODO: Configure BARs.  */
 
     /* DRAM at 0x40000000 */
-    memory_region_init_ram(ram, "mcf5208.ram", ram_size);
+    memory_region_init_ram(ram, NULL, "mcf5208.ram", ram_size);
     vmstate_register_ram_global(ram);
     memory_region_add_subregion(address_space_mem, 0x40000000, ram);
 
     /* Internal SRAM.  */
-    memory_region_init_ram(sram, "mcf5208.sram", 16384);
+    memory_region_init_ram(sram, NULL, "mcf5208.sram", 16384);
     vmstate_register_ram_global(sram);
     memory_region_add_subregion(address_space_mem, 0x80000000, sram);
 
diff --git a/hw/m68k/mcf_intc.c b/hw/m68k/mcf_intc.c
index cfe660d..621423c 100644
--- a/hw/m68k/mcf_intc.c
+++ b/hw/m68k/mcf_intc.c
@@ -147,7 +147,7 @@ qemu_irq *mcf_intc_init(MemoryRegion *sysmem,
     s->cpu = cpu;
     mcf_intc_reset(s);
 
-    memory_region_init_io(&s->iomem, &mcf_intc_ops, s, "mcf", 0x100);
+    memory_region_init_io(&s->iomem, NULL, &mcf_intc_ops, s, "mcf", 0x100);
     memory_region_add_subregion(sysmem, base, &s->iomem);
 
     return qemu_allocate_irqs(mcf_intc_set_irq, s, 64);
diff --git a/hw/microblaze/petalogix_ml605_mmu.c b/hw/microblaze/petalogix_ml605_mmu.c
index 3340468..989da25 100644
--- a/hw/microblaze/petalogix_ml605_mmu.c
+++ b/hw/microblaze/petalogix_ml605_mmu.c
@@ -98,12 +98,12 @@ petalogix_ml605_init(QEMUMachineInitArgs *args)
     env = &cpu->env;
 
     /* Attach emulated BRAM through the LMB.  */
-    memory_region_init_ram(phys_lmb_bram, "petalogix_ml605.lmb_bram",
+    memory_region_init_ram(phys_lmb_bram, NULL, "petalogix_ml605.lmb_bram",
                            LMB_BRAM_SIZE);
     vmstate_register_ram_global(phys_lmb_bram);
     memory_region_add_subregion(address_space_mem, 0x00000000, phys_lmb_bram);
 
-    memory_region_init_ram(phys_ram, "petalogix_ml605.ram", ram_size);
+    memory_region_init_ram(phys_ram, NULL, "petalogix_ml605.ram", ram_size);
     vmstate_register_ram_global(phys_ram);
     memory_region_add_subregion(address_space_mem, ddr_base, phys_ram);
 
diff --git a/hw/microblaze/petalogix_s3adsp1800_mmu.c b/hw/microblaze/petalogix_s3adsp1800_mmu.c
index b3bcd4e..a461494 100644
--- a/hw/microblaze/petalogix_s3adsp1800_mmu.c
+++ b/hw/microblaze/petalogix_s3adsp1800_mmu.c
@@ -80,12 +80,12 @@ petalogix_s3adsp1800_init(QEMUMachineInitArgs *args)
     env = &cpu->env;
 
     /* Attach emulated BRAM through the LMB.  */
-    memory_region_init_ram(phys_lmb_bram,
+    memory_region_init_ram(phys_lmb_bram, NULL,
                            "petalogix_s3adsp1800.lmb_bram", LMB_BRAM_SIZE);
     vmstate_register_ram_global(phys_lmb_bram);
     memory_region_add_subregion(sysmem, 0x00000000, phys_lmb_bram);
 
-    memory_region_init_ram(phys_ram, "petalogix_s3adsp1800.ram", ram_size);
+    memory_region_init_ram(phys_ram, NULL, "petalogix_s3adsp1800.ram", ram_size);
     vmstate_register_ram_global(phys_ram);
     memory_region_add_subregion(sysmem, ddr_base, phys_ram);
 
diff --git a/hw/mips/gt64xxx_pci.c b/hw/mips/gt64xxx_pci.c
index 189e865..d2739eb 100644
--- a/hw/mips/gt64xxx_pci.c
+++ b/hw/mips/gt64xxx_pci.c
@@ -1108,7 +1108,7 @@ PCIBus *gt64120_register(qemu_irq *pic)
                                 get_system_memory(),
                                 get_system_io(),
                                 PCI_DEVFN(18, 0), 4, TYPE_PCI_BUS);
-    memory_region_init_io(&d->ISD_mem, &isd_mem_ops, d, "isd-mem", 0x1000);
+    memory_region_init_io(&d->ISD_mem, NULL, &isd_mem_ops, d, "isd-mem", 0x1000);
 
     pci_create_simple(phb->bus, PCI_DEVFN(0, 0), "gt64120_pci");
     return phb->bus;
diff --git a/hw/mips/mips_fulong2e.c b/hw/mips/mips_fulong2e.c
index 1aac93a..74a41f6 100644
--- a/hw/mips/mips_fulong2e.c
+++ b/hw/mips/mips_fulong2e.c
@@ -300,9 +300,9 @@ static void mips_fulong2e_init(QEMUMachineInitArgs *args)
     bios_size = 1024 * 1024;
 
     /* allocate RAM */
-    memory_region_init_ram(ram, "fulong2e.ram", ram_size);
+    memory_region_init_ram(ram, NULL, "fulong2e.ram", ram_size);
     vmstate_register_ram_global(ram);
-    memory_region_init_ram(bios, "fulong2e.bios", bios_size);
+    memory_region_init_ram(bios, NULL, "fulong2e.bios", bios_size);
     vmstate_register_ram_global(bios);
     memory_region_set_readonly(bios, true);
 
diff --git a/hw/mips/mips_jazz.c b/hw/mips/mips_jazz.c
index 94d9570..39668a5 100644
--- a/hw/mips/mips_jazz.c
+++ b/hw/mips/mips_jazz.c
@@ -152,14 +152,14 @@ static void mips_jazz_init(MemoryRegion *address_space,
     qemu_register_reset(main_cpu_reset, cpu);
 
     /* allocate RAM */
-    memory_region_init_ram(ram, "mips_jazz.ram", ram_size);
+    memory_region_init_ram(ram, NULL, "mips_jazz.ram", ram_size);
     vmstate_register_ram_global(ram);
     memory_region_add_subregion(address_space, 0, ram);
 
-    memory_region_init_ram(bios, "mips_jazz.bios", MAGNUM_BIOS_SIZE);
+    memory_region_init_ram(bios, NULL, "mips_jazz.bios", MAGNUM_BIOS_SIZE);
     vmstate_register_ram_global(bios);
     memory_region_set_readonly(bios, true);
-    memory_region_init_alias(bios2, "mips_jazz.bios", bios,
+    memory_region_init_alias(bios2, NULL, "mips_jazz.bios", bios,
                              0, MAGNUM_BIOS_SIZE);
     memory_region_add_subregion(address_space, 0x1fc00000LL, bios);
     memory_region_add_subregion(address_space, 0xfff00000LL, bios2);
@@ -188,7 +188,7 @@ static void mips_jazz_init(MemoryRegion *address_space,
     /* Chipset */
     rc4030_opaque = rc4030_init(env->irq[6], env->irq[3], &rc4030, &dmas,
                                 address_space);
-    memory_region_init_io(dma_dummy, &dma_dummy_ops, NULL, "dummy_dma", 0x1000);
+    memory_region_init_io(dma_dummy, NULL, &dma_dummy_ops, NULL, "dummy_dma", 0x1000);
     memory_region_add_subregion(address_space, 0x8000d000, dma_dummy);
 
     /* ISA devices */
@@ -216,7 +216,7 @@ static void mips_jazz_init(MemoryRegion *address_space,
         {
             /* Simple ROM, so user doesn't have to provide one */
             MemoryRegion *rom_mr = g_new(MemoryRegion, 1);
-            memory_region_init_ram(rom_mr, "g364fb.rom", 0x80000);
+            memory_region_init_ram(rom_mr, NULL, "g364fb.rom", 0x80000);
             vmstate_register_ram_global(rom_mr);
             memory_region_set_readonly(rom_mr, true);
             uint8_t *rom = memory_region_get_ram_ptr(rom_mr);
@@ -266,7 +266,7 @@ static void mips_jazz_init(MemoryRegion *address_space,
 
     /* Real time clock */
     rtc_init(isa_bus, 1980, NULL);
-    memory_region_init_io(rtc, &rtc_ops, NULL, "rtc", 0x1000);
+    memory_region_init_io(rtc, NULL, &rtc_ops, NULL, "rtc", 0x1000);
     memory_region_add_subregion(address_space, 0x80004000, rtc);
 
     /* Keyboard (i8042) */
diff --git a/hw/mips/mips_malta.c b/hw/mips/mips_malta.c
index 5033d51..a9a83eb 100644
--- a/hw/mips/mips_malta.c
+++ b/hw/mips/mips_malta.c
@@ -446,11 +446,11 @@ static MaltaFPGAState *malta_fpga_init(MemoryRegion *address_space,
 
     s = (MaltaFPGAState *)g_malloc0(sizeof(MaltaFPGAState));
 
-    memory_region_init_io(&s->iomem, &malta_fpga_ops, s,
+    memory_region_init_io(&s->iomem, NULL, &malta_fpga_ops, s,
                           "malta-fpga", 0x100000);
-    memory_region_init_alias(&s->iomem_lo, "malta-fpga",
+    memory_region_init_alias(&s->iomem_lo, NULL, "malta-fpga",
                              &s->iomem, 0, 0x900);
-    memory_region_init_alias(&s->iomem_hi, "malta-fpga",
+    memory_region_init_alias(&s->iomem_hi, NULL, "malta-fpga",
                              &s->iomem, 0xa00, 0x10000-0xa00);
 
     memory_region_add_subregion(address_space, base, &s->iomem_lo);
@@ -853,7 +853,7 @@ void mips_malta_init(QEMUMachineInitArgs *args)
                 ((unsigned int)ram_size / (1 << 20)));
         exit(1);
     }
-    memory_region_init_ram(ram, "mips_malta.ram", ram_size);
+    memory_region_init_ram(ram, NULL, "mips_malta.ram", ram_size);
     vmstate_register_ram_global(ram);
     memory_region_add_subregion(system_memory, 0, ram);
 
@@ -927,7 +927,7 @@ void mips_malta_init(QEMUMachineInitArgs *args)
     }
 
     /* Map the BIOS at a 2nd physical location, as on the real board. */
-    memory_region_init_alias(bios_alias, "bios.1fc", bios, 0, BIOS_SIZE);
+    memory_region_init_alias(bios_alias, NULL, "bios.1fc", bios, 0, BIOS_SIZE);
     memory_region_add_subregion(system_memory, RESET_ADDRESS, bios_alias);
 
     /* Board ID = 0x420 (Malta Board with CoreLV)
diff --git a/hw/mips/mips_mipssim.c b/hw/mips/mips_mipssim.c
index d1681ec..a10cf13 100644
--- a/hw/mips/mips_mipssim.c
+++ b/hw/mips/mips_mipssim.c
@@ -168,9 +168,9 @@ mips_mipssim_init(QEMUMachineInitArgs *args)
     qemu_register_reset(main_cpu_reset, reset_info);
 
     /* Allocate RAM. */
-    memory_region_init_ram(ram, "mips_mipssim.ram", ram_size);
+    memory_region_init_ram(ram, NULL, "mips_mipssim.ram", ram_size);
     vmstate_register_ram_global(ram);
-    memory_region_init_ram(bios, "mips_mipssim.bios", BIOS_SIZE);
+    memory_region_init_ram(bios, NULL, "mips_mipssim.bios", BIOS_SIZE);
     vmstate_register_ram_global(bios);
     memory_region_set_readonly(bios, true);
 
diff --git a/hw/mips/mips_r4k.c b/hw/mips/mips_r4k.c
index 4646ab6..22beb0a 100644
--- a/hw/mips/mips_r4k.c
+++ b/hw/mips/mips_r4k.c
@@ -202,12 +202,12 @@ void mips_r4k_init(QEMUMachineInitArgs *args)
                 ((unsigned int)ram_size / (1 << 20)));
         exit(1);
     }
-    memory_region_init_ram(ram, "mips_r4k.ram", ram_size);
+    memory_region_init_ram(ram, NULL, "mips_r4k.ram", ram_size);
     vmstate_register_ram_global(ram);
 
     memory_region_add_subregion(address_space_mem, 0, ram);
 
-    memory_region_init_io(iomem, &mips_qemu_ops, NULL, "mips-qemu", 0x10000);
+    memory_region_init_io(iomem, NULL, &mips_qemu_ops, NULL, "mips-qemu", 0x10000);
     memory_region_add_subregion(address_space_mem, 0x1fbf0000, iomem);
 
     /* Try to load a BIOS image. If this fails, we continue regardless,
@@ -229,7 +229,7 @@ void mips_r4k_init(QEMUMachineInitArgs *args)
 #endif
     if ((bios_size > 0) && (bios_size <= BIOS_SIZE)) {
         bios = g_new(MemoryRegion, 1);
-        memory_region_init_ram(bios, "mips_r4k.bios", BIOS_SIZE);
+        memory_region_init_ram(bios, NULL, "mips_r4k.bios", BIOS_SIZE);
         vmstate_register_ram_global(bios);
         memory_region_set_readonly(bios, true);
         memory_region_add_subregion(get_system_memory(), 0x1fc00000, bios);
diff --git a/hw/misc/a9scu.c b/hw/misc/a9scu.c
index 05897c2..c8f26f9 100644
--- a/hw/misc/a9scu.c
+++ b/hw/misc/a9scu.c
@@ -119,7 +119,7 @@ static void a9_scu_realize(DeviceState *dev, Error ** errp)
     A9SCUState *s = A9_SCU(dev);
     SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
 
-    memory_region_init_io(&s->iomem, &a9_scu_ops, s, "a9-scu", 0x100);
+    memory_region_init_io(&s->iomem, NULL, &a9_scu_ops, s, "a9-scu", 0x100);
     sysbus_init_mmio(sbd, &s->iomem);
 }
 
diff --git a/hw/misc/applesmc.c b/hw/misc/applesmc.c
index 83468dc..ca4077f 100644
--- a/hw/misc/applesmc.c
+++ b/hw/misc/applesmc.c
@@ -230,12 +230,12 @@ static void applesmc_isa_realize(DeviceState *dev, Error **errp)
 {
     AppleSMCState *s = APPLE_SMC(dev);
 
-    memory_region_init_io(&s->io_data, &applesmc_data_io_ops, s,
+    memory_region_init_io(&s->io_data, NULL, &applesmc_data_io_ops, s,
                           "applesmc-data", 4);
     isa_register_ioport(&s->parent_obj, &s->io_data,
                         s->iobase + APPLESMC_DATA_PORT);
 
-    memory_region_init_io(&s->io_cmd, &applesmc_cmd_io_ops, s,
+    memory_region_init_io(&s->io_cmd, NULL, &applesmc_cmd_io_ops, s,
                           "applesmc-cmd", 4);
     isa_register_ioport(&s->parent_obj, &s->io_cmd,
                         s->iobase + APPLESMC_CMD_PORT);
diff --git a/hw/misc/arm_l2x0.c b/hw/misc/arm_l2x0.c
index eb4427d..954343f 100644
--- a/hw/misc/arm_l2x0.c
+++ b/hw/misc/arm_l2x0.c
@@ -157,7 +157,7 @@ static int l2x0_priv_init(SysBusDevice *dev)
 {
     l2x0_state *s = FROM_SYSBUS(l2x0_state, dev);
 
-    memory_region_init_io(&s->iomem, &l2x0_mem_ops, s, "l2x0_cc", 0x1000);
+    memory_region_init_io(&s->iomem, NULL, &l2x0_mem_ops, s, "l2x0_cc", 0x1000);
     sysbus_init_mmio(dev, &s->iomem);
     return 0;
 }
diff --git a/hw/misc/arm_sysctl.c b/hw/misc/arm_sysctl.c
index c8b55a8..9b07355 100644
--- a/hw/misc/arm_sysctl.c
+++ b/hw/misc/arm_sysctl.c
@@ -589,7 +589,7 @@ static void arm_sysctl_init(Object *obj)
     SysBusDevice *sd = SYS_BUS_DEVICE(obj);
     arm_sysctl_state *s = FROM_SYSBUS(arm_sysctl_state, sd);
 
-    memory_region_init_io(&s->iomem, &arm_sysctl_ops, s, "arm-sysctl", 0x1000);
+    memory_region_init_io(&s->iomem, NULL, &arm_sysctl_ops, s, "arm-sysctl", 0x1000);
     sysbus_init_mmio(sd, &s->iomem);
     qdev_init_gpio_in(dev, arm_sysctl_gpio_set, 2);
     qdev_init_gpio_out(dev, &s->pl110_mux_ctrl, 1);
diff --git a/hw/misc/debugexit.c b/hw/misc/debugexit.c
index ee254e4..e3a13f0 100644
--- a/hw/misc/debugexit.c
+++ b/hw/misc/debugexit.c
@@ -40,7 +40,7 @@ static void debug_exit_realizefn(DeviceState *d, Error **errp)
     ISADevice *dev = ISA_DEVICE(d);
     ISADebugExitState *isa = ISA_DEBUG_EXIT_DEVICE(d);
 
-    memory_region_init_io(&isa->io, &debug_exit_ops, isa,
+    memory_region_init_io(&isa->io, NULL, &debug_exit_ops, isa,
                           TYPE_ISA_DEBUG_EXIT_DEVICE, isa->iosize);
     memory_region_add_subregion(isa_address_space_io(dev),
                                 isa->iobase, &isa->io);
diff --git a/hw/misc/eccmemctl.c b/hw/misc/eccmemctl.c
index 6f4a407..71d62cc 100644
--- a/hw/misc/eccmemctl.c
+++ b/hw/misc/eccmemctl.c
@@ -296,11 +296,11 @@ static int ecc_init1(SysBusDevice *dev)
 
     sysbus_init_irq(dev, &s->irq);
     s->regs[0] = s->version;
-    memory_region_init_io(&s->iomem, &ecc_mem_ops, s, "ecc", ECC_SIZE);
+    memory_region_init_io(&s->iomem, NULL, &ecc_mem_ops, s, "ecc", ECC_SIZE);
     sysbus_init_mmio(dev, &s->iomem);
 
     if (s->version == ECC_MCC) { // SS-600MP only
-        memory_region_init_io(&s->iomem_diag, &ecc_diag_mem_ops, s,
+        memory_region_init_io(&s->iomem_diag, NULL, &ecc_diag_mem_ops, s,
                               "ecc.diag", ECC_DIAG_SIZE);
         sysbus_init_mmio(dev, &s->iomem_diag);
     }
diff --git a/hw/misc/exynos4210_pmu.c b/hw/misc/exynos4210_pmu.c
index ba5aa8d..465e72f 100644
--- a/hw/misc/exynos4210_pmu.c
+++ b/hw/misc/exynos4210_pmu.c
@@ -458,7 +458,7 @@ static int exynos4210_pmu_init(SysBusDevice *dev)
     Exynos4210PmuState *s = FROM_SYSBUS(Exynos4210PmuState, dev);
 
     /* memory mapping */
-    memory_region_init_io(&s->iomem, &exynos4210_pmu_ops, s, "exynos4210.pmu",
+    memory_region_init_io(&s->iomem, NULL, &exynos4210_pmu_ops, s, "exynos4210.pmu",
                           EXYNOS4210_PMU_REGS_MEM_SIZE);
     sysbus_init_mmio(dev, &s->iomem);
     return 0;
diff --git a/hw/misc/imx_ccm.c b/hw/misc/imx_ccm.c
index 427ce5c..863c219 100644
--- a/hw/misc/imx_ccm.c
+++ b/hw/misc/imx_ccm.c
@@ -281,7 +281,7 @@ static int imx_ccm_init(SysBusDevice *dev)
 {
     IMXCCMState *s = FROM_SYSBUS(typeof(*s), dev);
 
-    memory_region_init_io(&s->iomem, &imx_ccm_ops, s, "imx_ccm", 0x1000);
+    memory_region_init_io(&s->iomem, NULL, &imx_ccm_ops, s, "imx_ccm", 0x1000);
     sysbus_init_mmio(dev, &s->iomem);
 
     return 0;
diff --git a/hw/misc/ivshmem.c b/hw/misc/ivshmem.c
index 5658f73..522740d 100644
--- a/hw/misc/ivshmem.c
+++ b/hw/misc/ivshmem.c
@@ -339,7 +339,7 @@ static void create_shared_memory_BAR(IVShmemState *s, int fd) {
 
     ptr = mmap(0, s->ivshmem_size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
 
-    memory_region_init_ram_ptr(&s->ivshmem, "ivshmem.bar2",
+    memory_region_init_ram_ptr(&s->ivshmem, NULL, "ivshmem.bar2",
                                s->ivshmem_size, ptr);
     vmstate_register_ram(&s->ivshmem, &s->dev.qdev);
     memory_region_add_subregion(&s->bar, 0, &s->ivshmem);
@@ -467,7 +467,7 @@ static void ivshmem_read(void *opaque, const uint8_t * buf, int flags)
         /* mmap the region and map into the BAR2 */
         map_ptr = mmap(0, s->ivshmem_size, PROT_READ|PROT_WRITE, MAP_SHARED,
                                                             incoming_fd, 0);
-        memory_region_init_ram_ptr(&s->ivshmem,
+        memory_region_init_ram_ptr(&s->ivshmem, NULL,
                                    "ivshmem.bar2", s->ivshmem_size, map_ptr);
         vmstate_register_ram(&s->ivshmem, &s->dev.qdev);
 
@@ -685,14 +685,14 @@ static int pci_ivshmem_init(PCIDevice *dev)
 
     s->shm_fd = 0;
 
-    memory_region_init_io(&s->ivshmem_mmio, &ivshmem_mmio_ops, s,
+    memory_region_init_io(&s->ivshmem_mmio, NULL, &ivshmem_mmio_ops, s,
                           "ivshmem-mmio", IVSHMEM_REG_BAR_SIZE);
 
     /* region for registers*/
     pci_register_bar(&s->dev, 0, PCI_BASE_ADDRESS_SPACE_MEMORY,
                      &s->ivshmem_mmio);
 
-    memory_region_init(&s->bar, "ivshmem-bar2-container", s->ivshmem_size);
+    memory_region_init(&s->bar, NULL, "ivshmem-bar2-container", s->ivshmem_size);
     s->ivshmem_attr = PCI_BASE_ADDRESS_SPACE_MEMORY |
         PCI_BASE_ADDRESS_MEM_PREFETCH;
     if (s->ivshmem_64bit) {
diff --git a/hw/misc/lm32_sys.c b/hw/misc/lm32_sys.c
index aeaf2b7..accfbe3 100644
--- a/hw/misc/lm32_sys.c
+++ b/hw/misc/lm32_sys.c
@@ -117,7 +117,7 @@ static int lm32_sys_init(SysBusDevice *dev)
 {
     LM32SysState *s = FROM_SYSBUS(typeof(*s), dev);
 
-    memory_region_init_io(&s->iomem, &sys_ops , s, "sys", R_MAX * 4);
+    memory_region_init_io(&s->iomem, NULL, &sys_ops , s, "sys", R_MAX * 4);
     sysbus_init_mmio(dev, &s->iomem);
 
     /* Note: This device is not created in the board initialization,
diff --git a/hw/misc/macio/cuda.c b/hw/misc/macio/cuda.c
index f797796..c0fd7da 100644
--- a/hw/misc/macio/cuda.c
+++ b/hw/misc/macio/cuda.c
@@ -703,7 +703,7 @@ static void cuda_initfn(Object *obj)
     CUDAState *s = CUDA(obj);
     int i;
 
-    memory_region_init_io(&s->mem, &cuda_ops, s, "cuda", 0x2000);
+    memory_region_init_io(&s->mem, NULL, &cuda_ops, s, "cuda", 0x2000);
     sysbus_init_mmio(d, &s->mem);
     sysbus_init_irq(d, &s->irq);
 
diff --git a/hw/misc/macio/mac_dbdma.c b/hw/misc/macio/mac_dbdma.c
index 2fc7f87..a1d7862 100644
--- a/hw/misc/macio/mac_dbdma.c
+++ b/hw/misc/macio/mac_dbdma.c
@@ -848,7 +848,7 @@ void* DBDMA_init (MemoryRegion **dbdma_mem)
 
     s = g_malloc0(sizeof(DBDMAState));
 
-    memory_region_init_io(&s->mem, &dbdma_ops, s, "dbdma", 0x1000);
+    memory_region_init_io(&s->mem, NULL, &dbdma_ops, s, "dbdma", 0x1000);
     *dbdma_mem = &s->mem;
     vmstate_register(NULL, -1, &vmstate_dbdma, s);
     qemu_register_reset(dbdma_reset, s);
diff --git a/hw/misc/macio/macio.c b/hw/misc/macio/macio.c
index 2f389dd..04e4c1d 100644
--- a/hw/misc/macio/macio.c
+++ b/hw/misc/macio/macio.c
@@ -222,7 +222,7 @@ static void macio_instance_init(Object *obj)
     MacIOState *s = MACIO(obj);
     MemoryRegion *dbdma_mem;
 
-    memory_region_init(&s->bar, "macio", 0x80000);
+    memory_region_init(&s->bar, NULL, "macio", 0x80000);
 
     object_initialize(&s->cuda, TYPE_CUDA);
     qdev_set_parent_bus(DEVICE(&s->cuda), sysbus_get_default());
diff --git a/hw/misc/milkymist-hpdmc.c b/hw/misc/milkymist-hpdmc.c
index d922f6f..f4826b9 100644
--- a/hw/misc/milkymist-hpdmc.c
+++ b/hw/misc/milkymist-hpdmc.c
@@ -127,7 +127,7 @@ static int milkymist_hpdmc_init(SysBusDevice *dev)
 {
     MilkymistHpdmcState *s = FROM_SYSBUS(typeof(*s), dev);
 
-    memory_region_init_io(&s->regs_region, &hpdmc_mmio_ops, s,
+    memory_region_init_io(&s->regs_region, NULL, &hpdmc_mmio_ops, s,
             "milkymist-hpdmc", R_MAX * 4);
     sysbus_init_mmio(dev, &s->regs_region);
 
diff --git a/hw/misc/milkymist-pfpu.c b/hw/misc/milkymist-pfpu.c
index fe1b039..0051bc9 100644
--- a/hw/misc/milkymist-pfpu.c
+++ b/hw/misc/milkymist-pfpu.c
@@ -497,7 +497,7 @@ static int milkymist_pfpu_init(SysBusDevice *dev)
 
     sysbus_init_irq(dev, &s->irq);
 
-    memory_region_init_io(&s->regs_region, &pfpu_mmio_ops, s,
+    memory_region_init_io(&s->regs_region, NULL, &pfpu_mmio_ops, s,
             "milkymist-pfpu", MICROCODE_END * 4);
     sysbus_init_mmio(dev, &s->regs_region);
 
diff --git a/hw/misc/mst_fpga.c b/hw/misc/mst_fpga.c
index 1dd1505..b727dab 100644
--- a/hw/misc/mst_fpga.c
+++ b/hw/misc/mst_fpga.c
@@ -208,7 +208,7 @@ static int mst_fpga_init(SysBusDevice *dev)
 	/* alloc the external 16 irqs */
 	qdev_init_gpio_in(&dev->qdev, mst_fpga_set_irq, MST_NUM_IRQS);
 
-	memory_region_init_io(&s->iomem, &mst_fpga_ops, s,
+	memory_region_init_io(&s->iomem, NULL, &mst_fpga_ops, s,
 			    "fpga", 0x00100000);
 	sysbus_init_mmio(dev, &s->iomem);
 	return 0;
diff --git a/hw/misc/omap_gpmc.c b/hw/misc/omap_gpmc.c
index 91adb66..2047274 100644
--- a/hw/misc/omap_gpmc.c
+++ b/hw/misc/omap_gpmc.c
@@ -413,7 +413,7 @@ static void omap_gpmc_cs_map(struct omap_gpmc_s *s, int cs)
      * constant), the mask should cause wrapping of the address space, so
      * that the same memory becomes accessible at every <i>size</i> bytes
      * starting from <i>base</i>.  */
-    memory_region_init(&f->container, "omap-gpmc-file", size);
+    memory_region_init(&f->container, NULL, "omap-gpmc-file", size);
     memory_region_add_subregion(&f->container, 0,
                                 omap_gpmc_cs_memregion(s, cs));
     memory_region_add_subregion(get_system_memory(), base,
@@ -826,7 +826,7 @@ struct omap_gpmc_s *omap_gpmc_init(struct omap_mpu_state_s *mpu,
     struct omap_gpmc_s *s = (struct omap_gpmc_s *)
             g_malloc0(sizeof(struct omap_gpmc_s));
 
-    memory_region_init_io(&s->iomem, &omap_gpmc_ops, s, "omap-gpmc", 0x1000);
+    memory_region_init_io(&s->iomem, NULL, &omap_gpmc_ops, s, "omap-gpmc", 0x1000);
     memory_region_add_subregion(get_system_memory(), base, &s->iomem);
 
     s->irq = irq;
@@ -843,14 +843,14 @@ struct omap_gpmc_s *omap_gpmc_init(struct omap_mpu_state_s *mpu,
      * guest-requested size.
      */
     for (cs = 0; cs < 8; cs++) {
-        memory_region_init_io(&s->cs_file[cs].nandiomem,
+        memory_region_init_io(&s->cs_file[cs].nandiomem, NULL,
                               &omap_nand_ops,
                               &s->cs_file[cs],
                               "omap-nand",
                               256 * 1024 * 1024);
     }
 
-    memory_region_init_io(&s->prefetch.iomem, &omap_prefetch_ops, s,
+    memory_region_init_io(&s->prefetch.iomem, NULL, &omap_prefetch_ops, s,
                           "omap-gpmc-prefetch", 256 * 1024 * 1024);
     return s;
 }
diff --git a/hw/misc/omap_l4.c b/hw/misc/omap_l4.c
index ac8251f..f237250 100644
--- a/hw/misc/omap_l4.c
+++ b/hw/misc/omap_l4.c
@@ -136,7 +136,7 @@ struct omap_target_agent_s *omap_l4ta_get(struct omap_l4_s *bus,
     ta->status = 0x00000000;
     ta->control = 0x00000200;	/* XXX 01000200 for L4TAO */
 
-    memory_region_init_io(&ta->iomem, &omap_l4ta_ops, ta, "omap.l4ta",
+    memory_region_init_io(&ta->iomem, NULL, &omap_l4ta_ops, ta, "omap.l4ta",
                           omap_l4_region_size(ta, info->ta_region));
     omap_l4_attach(ta, info->ta_region, &ta->iomem);
 
diff --git a/hw/misc/omap_sdrc.c b/hw/misc/omap_sdrc.c
index e38b571..ed62caf 100644
--- a/hw/misc/omap_sdrc.c
+++ b/hw/misc/omap_sdrc.c
@@ -161,7 +161,7 @@ struct omap_sdrc_s *omap_sdrc_init(MemoryRegion *sysmem,
 
     omap_sdrc_reset(s);
 
-    memory_region_init_io(&s->iomem, &omap_sdrc_ops, s, "omap.sdrc", 0x1000);
+    memory_region_init_io(&s->iomem, NULL, &omap_sdrc_ops, s, "omap.sdrc", 0x1000);
     memory_region_add_subregion(sysmem, base, &s->iomem);
 
     return s;
diff --git a/hw/misc/omap_tap.c b/hw/misc/omap_tap.c
index 99b70d5..9d2b710 100644
--- a/hw/misc/omap_tap.c
+++ b/hw/misc/omap_tap.c
@@ -110,7 +110,7 @@ static const MemoryRegionOps omap_tap_ops = {
 void omap_tap_init(struct omap_target_agent_s *ta,
                 struct omap_mpu_state_s *mpu)
 {
-    memory_region_init_io(&mpu->tap_iomem, &omap_tap_ops, mpu, "omap.tap",
+    memory_region_init_io(&mpu->tap_iomem, NULL, &omap_tap_ops, mpu, "omap.tap",
                           omap_l4_region_size(ta, 0));
     omap_l4_attach(ta, 0, &mpu->tap_iomem);
 }
diff --git a/hw/misc/pc-testdev.c b/hw/misc/pc-testdev.c
index e6707d6..31c9878 100644
--- a/hw/misc/pc-testdev.c
+++ b/hw/misc/pc-testdev.c
@@ -149,13 +149,13 @@ static void testdev_realizefn(DeviceState *d, Error **errp)
     MemoryRegion *mem = isa_address_space(isa);
     MemoryRegion *io = isa_address_space_io(isa);
 
-    memory_region_init_io(&dev->ioport, &test_ioport_ops, dev,
+    memory_region_init_io(&dev->ioport, NULL, &test_ioport_ops, dev,
                           "pc-testdev-ioport", 4);
-    memory_region_init_io(&dev->flush, &test_flush_ops, dev,
+    memory_region_init_io(&dev->flush, NULL, &test_flush_ops, dev,
                           "pc-testdev-flush-page", 4);
-    memory_region_init_io(&dev->irq, &test_irq_ops, dev,
+    memory_region_init_io(&dev->irq, NULL, &test_irq_ops, dev,
                           "pc-testdev-irq-line", 24);
-    memory_region_init_io(&dev->iomem, &test_iomem_ops, dev,
+    memory_region_init_io(&dev->iomem, NULL, &test_iomem_ops, dev,
                           "pc-testdev-iomem", IOMEM_LEN);
 
     memory_region_add_subregion(io,  0xe0,       &dev->ioport);
diff --git a/hw/misc/pci-testdev.c b/hw/misc/pci-testdev.c
index 71ce5a3..fb9a58c 100644
--- a/hw/misc/pci-testdev.c
+++ b/hw/misc/pci-testdev.c
@@ -236,9 +236,9 @@ static int pci_testdev_init(PCIDevice *pci_dev)
 
     pci_conf[PCI_INTERRUPT_PIN] = 0; /* no interrupt pin */
 
-    memory_region_init_io(&d->mmio, &pci_testdev_mmio_ops, d,
+    memory_region_init_io(&d->mmio, NULL, &pci_testdev_mmio_ops, d,
                           "pci-testdev-mmio", IOTEST_MEMSIZE * 2);
-    memory_region_init_io(&d->portio, &pci_testdev_pio_ops, d,
+    memory_region_init_io(&d->portio, NULL, &pci_testdev_pio_ops, d,
                           "pci-testdev-portio", IOTEST_IOSIZE * 2);
     pci_register_bar(&d->dev, 0, PCI_BASE_ADDRESS_SPACE_MEMORY, &d->mmio);
     pci_register_bar(&d->dev, 1, PCI_BASE_ADDRESS_SPACE_IO, &d->portio);
diff --git a/hw/misc/puv3_pm.c b/hw/misc/puv3_pm.c
index 0aacdc2..d4a863f 100644
--- a/hw/misc/puv3_pm.c
+++ b/hw/misc/puv3_pm.c
@@ -120,7 +120,7 @@ static int puv3_pm_init(SysBusDevice *dev)
 
     s->reg_PCGR = 0x0;
 
-    memory_region_init_io(&s->iomem, &puv3_pm_ops, s, "puv3_pm",
+    memory_region_init_io(&s->iomem, NULL, &puv3_pm_ops, s, "puv3_pm",
             PUV3_REGS_OFFSET);
     sysbus_init_mmio(dev, &s->iomem);
 
diff --git a/hw/misc/pvpanic.c b/hw/misc/pvpanic.c
index 060099b..00d6e63 100644
--- a/hw/misc/pvpanic.c
+++ b/hw/misc/pvpanic.c
@@ -90,7 +90,7 @@ static void pvpanic_isa_initfn(Object *obj)
 {
     PVPanicState *s = ISA_PVPANIC_DEVICE(obj);
 
-    memory_region_init_io(&s->io, &pvpanic_ops, s, "pvpanic", 1);
+    memory_region_init_io(&s->io, NULL, &pvpanic_ops, s, "pvpanic", 1);
 }
 
 static void pvpanic_isa_realizefn(DeviceState *dev, Error **errp)
diff --git a/hw/misc/pxa2xx_pcmcia.c b/hw/misc/pxa2xx_pcmcia.c
index 323d458..ef71a2a 100644
--- a/hw/misc/pxa2xx_pcmcia.c
+++ b/hw/misc/pxa2xx_pcmcia.c
@@ -128,7 +128,7 @@ PXA2xxPCMCIAState *pxa2xx_pcmcia_init(MemoryRegion *sysmem,
             g_malloc0(sizeof(PXA2xxPCMCIAState));
 
     /* Socket I/O Memory Space */
-    memory_region_init_io(&s->iomem, &pxa2xx_pcmcia_io_ops, s,
+    memory_region_init_io(&s->iomem, NULL, &pxa2xx_pcmcia_io_ops, s,
                           "pxa2xx-pcmcia-io", 0x04000000);
     memory_region_add_subregion(sysmem, base | 0x00000000,
                                 &s->iomem);
@@ -136,13 +136,13 @@ PXA2xxPCMCIAState *pxa2xx_pcmcia_init(MemoryRegion *sysmem,
     /* Then next 64 MB is reserved */
 
     /* Socket Attribute Memory Space */
-    memory_region_init_io(&s->attr_iomem, &pxa2xx_pcmcia_attr_ops, s,
+    memory_region_init_io(&s->attr_iomem, NULL, &pxa2xx_pcmcia_attr_ops, s,
                           "pxa2xx-pcmcia-attribute", 0x04000000);
     memory_region_add_subregion(sysmem, base | 0x08000000,
                                 &s->attr_iomem);
 
     /* Socket Common Memory Space */
-    memory_region_init_io(&s->common_iomem, &pxa2xx_pcmcia_common_ops, s,
+    memory_region_init_io(&s->common_iomem, NULL, &pxa2xx_pcmcia_common_ops, s,
                           "pxa2xx-pcmcia-common", 0x04000000);
     memory_region_add_subregion(sysmem, base | 0x0c000000,
                                 &s->common_iomem);
diff --git a/hw/misc/slavio_misc.c b/hw/misc/slavio_misc.c
index a7a93688..dbc6081 100644
--- a/hw/misc/slavio_misc.c
+++ b/hw/misc/slavio_misc.c
@@ -412,7 +412,7 @@ static int apc_init1(SysBusDevice *dev)
     sysbus_init_irq(dev, &s->cpu_halt);
 
     /* Power management (APC) XXX: not a Slavio device */
-    memory_region_init_io(&s->iomem, &apc_mem_ops, s,
+    memory_region_init_io(&s->iomem, NULL, &apc_mem_ops, s,
                           "apc", MISC_SIZE);
     sysbus_init_mmio(dev, &s->iomem);
     return 0;
@@ -427,39 +427,39 @@ static int slavio_misc_init1(SysBusDevice *dev)
 
     /* 8 bit registers */
     /* Slavio control */
-    memory_region_init_io(&s->cfg_iomem, &slavio_cfg_mem_ops, s,
+    memory_region_init_io(&s->cfg_iomem, NULL, &slavio_cfg_mem_ops, s,
                           "configuration", MISC_SIZE);
     sysbus_init_mmio(dev, &s->cfg_iomem);
 
     /* Diagnostics */
-    memory_region_init_io(&s->diag_iomem, &slavio_diag_mem_ops, s,
+    memory_region_init_io(&s->diag_iomem, NULL, &slavio_diag_mem_ops, s,
                           "diagnostic", MISC_SIZE);
     sysbus_init_mmio(dev, &s->diag_iomem);
 
     /* Modem control */
-    memory_region_init_io(&s->mdm_iomem, &slavio_mdm_mem_ops, s,
+    memory_region_init_io(&s->mdm_iomem, NULL, &slavio_mdm_mem_ops, s,
                           "modem", MISC_SIZE);
     sysbus_init_mmio(dev, &s->mdm_iomem);
 
     /* 16 bit registers */
     /* ss600mp diag LEDs */
-    memory_region_init_io(&s->led_iomem, &slavio_led_mem_ops, s,
+    memory_region_init_io(&s->led_iomem, NULL, &slavio_led_mem_ops, s,
                           "leds", MISC_SIZE);
     sysbus_init_mmio(dev, &s->led_iomem);
 
     /* 32 bit registers */
     /* System control */
-    memory_region_init_io(&s->sysctrl_iomem, &slavio_sysctrl_mem_ops, s,
+    memory_region_init_io(&s->sysctrl_iomem, NULL, &slavio_sysctrl_mem_ops, s,
                           "system-control", MISC_SIZE);
     sysbus_init_mmio(dev, &s->sysctrl_iomem);
 
     /* AUX 1 (Misc System Functions) */
-    memory_region_init_io(&s->aux1_iomem, &slavio_aux1_mem_ops, s,
+    memory_region_init_io(&s->aux1_iomem, NULL, &slavio_aux1_mem_ops, s,
                           "misc-system-functions", MISC_SIZE);
     sysbus_init_mmio(dev, &s->aux1_iomem);
 
     /* AUX 2 (Software Powerdown Control) */
-    memory_region_init_io(&s->aux2_iomem, &slavio_aux2_mem_ops, s,
+    memory_region_init_io(&s->aux2_iomem, NULL, &slavio_aux2_mem_ops, s,
                           "software-powerdown-control", MISC_SIZE);
     sysbus_init_mmio(dev, &s->aux2_iomem);
 
diff --git a/hw/misc/vfio.c b/hw/misc/vfio.c
index 52fb036..e2e957d 100644
--- a/hw/misc/vfio.c
+++ b/hw/misc/vfio.c
@@ -1154,7 +1154,7 @@ static void vfio_vga_probe_ati_3c3_quirk(VFIODevice *vdev)
     quirk->vdev = vdev;
     quirk->data = (physbar >> 8) & 0xff;
 
-    memory_region_init_io(&quirk->mem, &vfio_ati_3c3_quirk, quirk,
+    memory_region_init_io(&quirk->mem, NULL, &vfio_ati_3c3_quirk, quirk,
                           "vfio-ati-3c3-quirk", 1);
     memory_region_add_subregion(&vdev->vga.region[QEMU_PCI_VGA_IO_HI].mem, 3,
                                 &quirk->mem);
@@ -1245,7 +1245,7 @@ static void vfio_probe_ati_4010_quirk(VFIODevice *vdev, int nr)
     quirk = g_malloc0(sizeof(*quirk));
     quirk->vdev = vdev;
 
-    memory_region_init_io(&quirk->mem, &vfio_ati_4010_quirk, quirk,
+    memory_region_init_io(&quirk->mem, NULL, &vfio_ati_4010_quirk, quirk,
                           "vfio-ati-4010-quirk", 8);
     memory_region_add_subregion_overlap(&vdev->bars[nr].mem, 0, &quirk->mem, 1);
 
@@ -1331,7 +1331,7 @@ static void vfio_probe_ati_f10_quirk(VFIODevice *vdev, int nr)
     quirk = g_malloc0(sizeof(*quirk));
     quirk->vdev = vdev;
 
-    memory_region_init_io(&quirk->mem, &vfio_ati_f10_quirk, quirk,
+    memory_region_init_io(&quirk->mem, NULL, &vfio_ati_f10_quirk, quirk,
                           "vfio-ati-f10-quirk", 8);
     memory_region_add_subregion_overlap(&vdev->bars[nr].mem, 0, &quirk->mem, 1);
 
@@ -1451,7 +1451,7 @@ static void vfio_vga_probe_nvidia_3d0_quirk(VFIODevice *vdev)
     quirk = g_malloc0(sizeof(*quirk));
     quirk->vdev = vdev;
 
-    memory_region_init_io(&quirk->mem, &vfio_nvidia_3d0_quirk, quirk,
+    memory_region_init_io(&quirk->mem, NULL, &vfio_nvidia_3d0_quirk, quirk,
                           "vfio-nvidia-3d0-quirk", 6);
     memory_region_add_subregion(&vdev->vga.region[QEMU_PCI_VGA_IO_HI].mem,
                                 0x10, &quirk->mem);
@@ -1566,7 +1566,7 @@ static void vfio_probe_nvidia_bar5_window_quirk(VFIODevice *vdev, int nr)
     quirk = g_malloc0(sizeof(*quirk));
     quirk->vdev = vdev;
 
-    memory_region_init_io(&quirk->mem, &vfio_nvidia_bar5_window_quirk, quirk,
+    memory_region_init_io(&quirk->mem, NULL, &vfio_nvidia_bar5_window_quirk, quirk,
                           "vfio-nvidia-bar5-window-quirk", 16);
     memory_region_add_subregion_overlap(&vdev->bars[nr].mem, 0, &quirk->mem, 1);
 
@@ -1644,7 +1644,7 @@ static void vfio_probe_nvidia_bar0_88000_quirk(VFIODevice *vdev, int nr)
     quirk = g_malloc0(sizeof(*quirk));
     quirk->vdev = vdev;
 
-    memory_region_init_io(&quirk->mem, &vfio_nvidia_bar0_88000_quirk, quirk,
+    memory_region_init_io(&quirk->mem, NULL, &vfio_nvidia_bar0_88000_quirk, quirk,
                           "vfio-nvidia-bar0-88000-quirk",
                           TARGET_PAGE_ALIGN(PCIE_CONFIG_SPACE_SIZE));
     memory_region_add_subregion_overlap(&vdev->bars[nr].mem,
@@ -1723,7 +1723,7 @@ static void vfio_probe_nvidia_bar0_1800_quirk(VFIODevice *vdev, int nr)
     quirk = g_malloc0(sizeof(*quirk));
     quirk->vdev = vdev;
 
-    memory_region_init_io(&quirk->mem, &vfio_nvidia_bar0_1800_quirk, quirk,
+    memory_region_init_io(&quirk->mem, NULL, &vfio_nvidia_bar0_1800_quirk, quirk,
                           "vfio-nvidia-bar0-1800-quirk",
                           TARGET_PAGE_ALIGN(PCI_CONFIG_SPACE_SIZE));
     memory_region_add_subregion_overlap(&vdev->bars[nr].mem,
@@ -2228,11 +2228,11 @@ static int vfio_mmap_bar(VFIOBAR *bar, MemoryRegion *mem, MemoryRegion *submem,
             goto empty_region;
         }
 
-        memory_region_init_ram_ptr(submem, name, size, *map);
+        memory_region_init_ram_ptr(submem, NULL, name, size, *map);
     } else {
 empty_region:
         /* Create a zero sized sub-region to make cleanup easy. */
-        memory_region_init(submem, name, 0);
+        memory_region_init(submem, NULL, name, 0);
     }
 
     memory_region_add_subregion(mem, offset, submem);
@@ -2271,7 +2271,7 @@ static void vfio_map_bar(VFIODevice *vdev, int nr)
            ~PCI_BASE_ADDRESS_IO_MASK : ~PCI_BASE_ADDRESS_MEM_MASK);
 
     /* A "slow" read/write mapping underlies all BARs */
-    memory_region_init_io(&bar->mem, &vfio_bar_ops, bar, name, size);
+    memory_region_init_io(&bar->mem, NULL, &vfio_bar_ops, bar, name, size);
     pci_register_bar(&vdev->pdev, nr, type, &bar->mem);
 
     /*
@@ -2315,17 +2315,17 @@ static void vfio_map_bars(VFIODevice *vdev)
     }
 
     if (vdev->has_vga) {
-        memory_region_init_io(&vdev->vga.region[QEMU_PCI_VGA_MEM].mem,
+        memory_region_init_io(&vdev->vga.region[QEMU_PCI_VGA_MEM].mem, NULL,
                               &vfio_vga_ops,
                               &vdev->vga.region[QEMU_PCI_VGA_MEM],
                               "vfio-vga-mmio@0xa0000",
                               QEMU_PCI_VGA_MEM_SIZE);
-        memory_region_init_io(&vdev->vga.region[QEMU_PCI_VGA_IO_LO].mem,
+        memory_region_init_io(&vdev->vga.region[QEMU_PCI_VGA_IO_LO].mem, NULL,
                               &vfio_vga_ops,
                               &vdev->vga.region[QEMU_PCI_VGA_IO_LO],
                               "vfio-vga-io@0x3b0",
                               QEMU_PCI_VGA_IO_LO_SIZE);
-        memory_region_init_io(&vdev->vga.region[QEMU_PCI_VGA_IO_HI].mem,
+        memory_region_init_io(&vdev->vga.region[QEMU_PCI_VGA_IO_HI].mem, NULL,
                               &vfio_vga_ops,
                               &vdev->vga.region[QEMU_PCI_VGA_IO_HI],
                               "vfio-vga-io@0x3c0",
@@ -2588,7 +2588,7 @@ static int vfio_load_rom(VFIODevice *vdev)
     snprintf(name, sizeof(name), "vfio[%04x:%02x:%02x.%x].rom",
              vdev->host.domain, vdev->host.bus, vdev->host.slot,
              vdev->host.function);
-    memory_region_init_ram(&vdev->pdev.rom, name, size);
+    memory_region_init_ram(&vdev->pdev.rom, NULL, name, size);
     ptr = memory_region_get_ram_ptr(&vdev->pdev.rom);
     memset(ptr, 0xff, size);
 
diff --git a/hw/misc/vmport.c b/hw/misc/vmport.c
index eb9059e..831d534 100644
--- a/hw/misc/vmport.c
+++ b/hw/misc/vmport.c
@@ -142,7 +142,7 @@ static void vmport_realizefn(DeviceState *dev, Error **errp)
     ISADevice *isadev = ISA_DEVICE(dev);
     VMPortState *s = VMPORT(dev);
 
-    memory_region_init_io(&s->io, &vmport_ops, s, "vmport", 1);
+    memory_region_init_io(&s->io, NULL, &vmport_ops, s, "vmport", 1);
     isa_register_ioport(isadev, &s->io, 0x5658);
 
     port_state = s;
diff --git a/hw/misc/zynq_slcr.c b/hw/misc/zynq_slcr.c
index 8418327..d7c2d19 100644
--- a/hw/misc/zynq_slcr.c
+++ b/hw/misc/zynq_slcr.c
@@ -494,7 +494,7 @@ static int zynq_slcr_init(SysBusDevice *dev)
 {
     ZynqSLCRState *s = FROM_SYSBUS(ZynqSLCRState, dev);
 
-    memory_region_init_io(&s->iomem, &slcr_ops, s, "slcr", 0x1000);
+    memory_region_init_io(&s->iomem, NULL, &slcr_ops, s, "slcr", 0x1000);
     sysbus_init_mmio(dev, &s->iomem);
 
     return 0;
diff --git a/hw/moxie/moxiesim.c b/hw/moxie/moxiesim.c
index 649f9a7..ef4f3a8 100644
--- a/hw/moxie/moxiesim.c
+++ b/hw/moxie/moxiesim.c
@@ -136,11 +136,11 @@ static void moxiesim_init(QEMUMachineInitArgs *args)
     qemu_register_reset(main_cpu_reset, cpu);
 
     /* Allocate RAM. */
-    memory_region_init_ram(ram, "moxiesim.ram", ram_size);
+    memory_region_init_ram(ram, NULL, "moxiesim.ram", ram_size);
     vmstate_register_ram_global(ram);
     memory_region_add_subregion(address_space_mem, ram_base, ram);
 
-    memory_region_init_ram(rom, "moxie.rom", 128*0x1000);
+    memory_region_init_ram(rom, NULL, "moxie.rom", 128*0x1000);
     vmstate_register_ram_global(rom);
     memory_region_add_subregion(get_system_memory(), 0x1000, rom);
 
diff --git a/hw/net/cadence_gem.c b/hw/net/cadence_gem.c
index e177057..c94d3e7 100644
--- a/hw/net/cadence_gem.c
+++ b/hw/net/cadence_gem.c
@@ -1163,7 +1163,7 @@ static int gem_init(SysBusDevice *dev)
 
     s = FROM_SYSBUS(GemState, dev);
     gem_init_register_masks(s);
-    memory_region_init_io(&s->iomem, &gem_ops, s, "enet", sizeof(s->regs));
+    memory_region_init_io(&s->iomem, NULL, &gem_ops, s, "enet", sizeof(s->regs));
     sysbus_init_mmio(dev, &s->iomem);
     sysbus_init_irq(dev, &s->irq);
     qemu_macaddr_default_if_unset(&s->conf.macaddr);
diff --git a/hw/net/dp8393x.c b/hw/net/dp8393x.c
index 2289f08..049aa70 100644
--- a/hw/net/dp8393x.c
+++ b/hw/net/dp8393x.c
@@ -908,7 +908,7 @@ void dp83932_init(NICInfo *nd, hwaddr base, int it_shift,
     qemu_register_reset(nic_reset, s);
     nic_reset(s);
 
-    memory_region_init_io(&s->mmio, &dp8393x_ops, s,
+    memory_region_init_io(&s->mmio, NULL, &dp8393x_ops, s,
                           "dp8393x", 0x40 << it_shift);
     memory_region_add_subregion(address_space, base, &s->mmio);
 }
diff --git a/hw/net/e1000.c b/hw/net/e1000.c
index e6f46f0..e5c0978 100644
--- a/hw/net/e1000.c
+++ b/hw/net/e1000.c
@@ -1276,13 +1276,13 @@ e1000_mmio_setup(E1000State *d)
         E1000_IMC, E1000_TCTL, E1000_TDT, PNPMMIO_SIZE
     };
 
-    memory_region_init_io(&d->mmio, &e1000_mmio_ops, d, "e1000-mmio",
+    memory_region_init_io(&d->mmio, NULL, &e1000_mmio_ops, d, "e1000-mmio",
                           PNPMMIO_SIZE);
     memory_region_add_coalescing(&d->mmio, 0, excluded_regs[0]);
     for (i = 0; excluded_regs[i] != PNPMMIO_SIZE; i++)
         memory_region_add_coalescing(&d->mmio, excluded_regs[i] + 4,
                                      excluded_regs[i+1] - excluded_regs[i] - 4);
-    memory_region_init_io(&d->io, &e1000_io_ops, d, "e1000-io", IOPORT_SIZE);
+    memory_region_init_io(&d->io, NULL, &e1000_io_ops, d, "e1000-io", IOPORT_SIZE);
 }
 
 static void
diff --git a/hw/net/eepro100.c b/hw/net/eepro100.c
index dc99ea6..abfcdbd 100644
--- a/hw/net/eepro100.c
+++ b/hw/net/eepro100.c
@@ -1876,14 +1876,14 @@ static int e100_nic_init(PCIDevice *pci_dev)
     s->eeprom = eeprom93xx_new(&pci_dev->qdev, EEPROM_SIZE);
 
     /* Handler for memory-mapped I/O */
-    memory_region_init_io(&s->mmio_bar, &eepro100_ops, s, "eepro100-mmio",
+    memory_region_init_io(&s->mmio_bar, NULL, &eepro100_ops, s, "eepro100-mmio",
                           PCI_MEM_SIZE);
     pci_register_bar(&s->dev, 0, PCI_BASE_ADDRESS_MEM_PREFETCH, &s->mmio_bar);
-    memory_region_init_io(&s->io_bar, &eepro100_ops, s, "eepro100-io",
+    memory_region_init_io(&s->io_bar, NULL, &eepro100_ops, s, "eepro100-io",
                           PCI_IO_SIZE);
     pci_register_bar(&s->dev, 1, PCI_BASE_ADDRESS_SPACE_IO, &s->io_bar);
     /* FIXME: flash aliases to mmio?! */
-    memory_region_init_io(&s->flash_bar, &eepro100_ops, s, "eepro100-flash",
+    memory_region_init_io(&s->flash_bar, NULL, &eepro100_ops, s, "eepro100-flash",
                           PCI_FLASH_SIZE);
     pci_register_bar(&s->dev, 2, 0, &s->flash_bar);
 
diff --git a/hw/net/etraxfs_eth.c b/hw/net/etraxfs_eth.c
index 1039913..2ade0c0 100644
--- a/hw/net/etraxfs_eth.c
+++ b/hw/net/etraxfs_eth.c
@@ -610,7 +610,7 @@ static int fs_eth_init(SysBusDevice *dev)
     s->dma_in->client.opaque = s;
     s->dma_in->client.pull = NULL;
 
-    memory_region_init_io(&s->mmio, &eth_ops, s, "etraxfs-eth", 0x5c);
+    memory_region_init_io(&s->mmio, NULL, &eth_ops, s, "etraxfs-eth", 0x5c);
     sysbus_init_mmio(dev, &s->mmio);
 
     qemu_macaddr_default_if_unset(&s->conf.macaddr);
diff --git a/hw/net/lan9118.c b/hw/net/lan9118.c
index 403fb86..ce68399 100644
--- a/hw/net/lan9118.c
+++ b/hw/net/lan9118.c
@@ -1328,7 +1328,7 @@ static int lan9118_init1(SysBusDevice *dev)
     const MemoryRegionOps *mem_ops =
             s->mode_16bit ? &lan9118_16bit_mem_ops : &lan9118_mem_ops;
 
-    memory_region_init_io(&s->mmio, mem_ops, s, "lan9118-mmio", 0x100);
+    memory_region_init_io(&s->mmio, NULL, mem_ops, s, "lan9118-mmio", 0x100);
     sysbus_init_mmio(dev, &s->mmio);
     sysbus_init_irq(dev, &s->irq);
     qemu_macaddr_default_if_unset(&s->conf.macaddr);
diff --git a/hw/net/lance.c b/hw/net/lance.c
index 187497c..1d3999d 100644
--- a/hw/net/lance.c
+++ b/hw/net/lance.c
@@ -117,7 +117,7 @@ static int lance_init(SysBusDevice *dev)
     SysBusPCNetState *d = FROM_SYSBUS(SysBusPCNetState, dev);
     PCNetState *s = &d->state;
 
-    memory_region_init_io(&s->mmio, &lance_mem_ops, d, "lance-mmio", 4);
+    memory_region_init_io(&s->mmio, NULL, &lance_mem_ops, d, "lance-mmio", 4);
 
     qdev_init_gpio_in(&dev->qdev, parent_lance_reset, 1);
 
diff --git a/hw/net/mcf_fec.c b/hw/net/mcf_fec.c
index 2ef5a0d..4bff3de 100644
--- a/hw/net/mcf_fec.c
+++ b/hw/net/mcf_fec.c
@@ -468,7 +468,7 @@ void mcf_fec_init(MemoryRegion *sysmem, NICInfo *nd,
     s->sysmem = sysmem;
     s->irq = irq;
 
-    memory_region_init_io(&s->iomem, &mcf_fec_ops, s, "fec", 0x400);
+    memory_region_init_io(&s->iomem, NULL, &mcf_fec_ops, s, "fec", 0x400);
     memory_region_add_subregion(sysmem, base, &s->iomem);
 
     s->conf.macaddr = nd->macaddr;
diff --git a/hw/net/milkymist-minimac2.c b/hw/net/milkymist-minimac2.c
index 4ef6318..73fe307 100644
--- a/hw/net/milkymist-minimac2.c
+++ b/hw/net/milkymist-minimac2.c
@@ -461,12 +461,12 @@ static int milkymist_minimac2_init(SysBusDevice *dev)
     sysbus_init_irq(dev, &s->rx_irq);
     sysbus_init_irq(dev, &s->tx_irq);
 
-    memory_region_init_io(&s->regs_region, &minimac2_ops, s,
+    memory_region_init_io(&s->regs_region, NULL, &minimac2_ops, s,
                           "milkymist-minimac2", R_MAX * 4);
     sysbus_init_mmio(dev, &s->regs_region);
 
     /* register buffers memory */
-    memory_region_init_ram(&s->buffers, "milkymist-minimac2.buffers",
+    memory_region_init_ram(&s->buffers, NULL, "milkymist-minimac2.buffers",
                            buffers_size);
     vmstate_register_ram_global(&s->buffers);
     s->rx0_buf = memory_region_get_ram_ptr(&s->buffers);
diff --git a/hw/net/mipsnet.c b/hw/net/mipsnet.c
index ac6193a..c973a21 100644
--- a/hw/net/mipsnet.c
+++ b/hw/net/mipsnet.c
@@ -235,7 +235,7 @@ static int mipsnet_sysbus_init(SysBusDevice *dev)
 {
     MIPSnetState *s = DO_UPCAST(MIPSnetState, busdev, dev);
 
-    memory_region_init_io(&s->io, &mipsnet_ioport_ops, s, "mipsnet-io", 36);
+    memory_region_init_io(&s->io, NULL, &mipsnet_ioport_ops, s, "mipsnet-io", 36);
     sysbus_init_mmio(dev, &s->io);
     sysbus_init_irq(dev, &s->irq);
 
diff --git a/hw/net/ne2000.c b/hw/net/ne2000.c
index 33ee03e..00940af 100644
--- a/hw/net/ne2000.c
+++ b/hw/net/ne2000.c
@@ -701,7 +701,7 @@ static const MemoryRegionOps ne2000_ops = {
 
 void ne2000_setup_io(NE2000State *s, unsigned size)
 {
-    memory_region_init_io(&s->io, &ne2000_ops, s, "ne2000", size);
+    memory_region_init_io(&s->io, NULL, &ne2000_ops, s, "ne2000", size);
 }
 
 static void ne2000_cleanup(NetClientState *nc)
diff --git a/hw/net/opencores_eth.c b/hw/net/opencores_eth.c
index be64bf2..a1baa3c 100644
--- a/hw/net/opencores_eth.c
+++ b/hw/net/opencores_eth.c
@@ -681,11 +681,11 @@ static int sysbus_open_eth_init(SysBusDevice *dev)
 {
     OpenEthState *s = DO_UPCAST(OpenEthState, dev, dev);
 
-    memory_region_init_io(&s->reg_io, &open_eth_reg_ops, s,
+    memory_region_init_io(&s->reg_io, NULL, &open_eth_reg_ops, s,
             "open_eth.regs", 0x54);
     sysbus_init_mmio(dev, &s->reg_io);
 
-    memory_region_init_io(&s->desc_io, &open_eth_desc_ops, s,
+    memory_region_init_io(&s->desc_io, NULL, &open_eth_desc_ops, s,
             "open_eth.desc", 0x400);
     sysbus_init_mmio(dev, &s->desc_io);
 
diff --git a/hw/net/pcnet-pci.c b/hw/net/pcnet-pci.c
index 9df2b87..e098bf2 100644
--- a/hw/net/pcnet-pci.c
+++ b/hw/net/pcnet-pci.c
@@ -315,10 +315,10 @@ static int pci_pcnet_init(PCIDevice *pci_dev)
     pci_conf[PCI_MAX_LAT] = 0xff;
 
     /* Handler for memory-mapped I/O */
-    memory_region_init_io(&d->state.mmio, &pcnet_mmio_ops, s, "pcnet-mmio",
+    memory_region_init_io(&d->state.mmio, NULL, &pcnet_mmio_ops, s, "pcnet-mmio",
                           PCNET_PNPMMIO_SIZE);
 
-    memory_region_init_io(&d->io_bar, &pcnet_io_ops, s, "pcnet-io",
+    memory_region_init_io(&d->io_bar, NULL, &pcnet_io_ops, s, "pcnet-io",
                           PCNET_IOPORT_SIZE);
     pci_register_bar(pci_dev, 0, PCI_BASE_ADDRESS_SPACE_IO, &d->io_bar);
 
diff --git a/hw/net/rtl8139.c b/hw/net/rtl8139.c
index 7993f9f..a96eb62 100644
--- a/hw/net/rtl8139.c
+++ b/hw/net/rtl8139.c
@@ -3486,8 +3486,8 @@ static int pci_rtl8139_init(PCIDevice *dev)
      * list bit in status register, and offset 0xdc seems unused. */
     pci_conf[PCI_CAPABILITY_LIST] = 0xdc;
 
-    memory_region_init_io(&s->bar_io, &rtl8139_io_ops, s, "rtl8139", 0x100);
-    memory_region_init_io(&s->bar_mem, &rtl8139_mmio_ops, s, "rtl8139", 0x100);
+    memory_region_init_io(&s->bar_io, NULL, &rtl8139_io_ops, s, "rtl8139", 0x100);
+    memory_region_init_io(&s->bar_mem, NULL, &rtl8139_mmio_ops, s, "rtl8139", 0x100);
     pci_register_bar(&s->dev, 0, PCI_BASE_ADDRESS_SPACE_IO, &s->bar_io);
     pci_register_bar(&s->dev, 1, PCI_BASE_ADDRESS_SPACE_MEMORY, &s->bar_mem);
 
diff --git a/hw/net/smc91c111.c b/hw/net/smc91c111.c
index c2feae6..6429709 100644
--- a/hw/net/smc91c111.c
+++ b/hw/net/smc91c111.c
@@ -747,7 +747,7 @@ static NetClientInfo net_smc91c111_info = {
 static int smc91c111_init1(SysBusDevice *dev)
 {
     smc91c111_state *s = FROM_SYSBUS(smc91c111_state, dev);
-    memory_region_init_io(&s->mmio, &smc91c111_mem_ops, s,
+    memory_region_init_io(&s->mmio, NULL, &smc91c111_mem_ops, s,
                           "smc91c111-mmio", 16);
     sysbus_init_mmio(dev, &s->mmio);
     sysbus_init_irq(dev, &s->irq);
diff --git a/hw/net/stellaris_enet.c b/hw/net/stellaris_enet.c
index 59b8456..b1394a2 100644
--- a/hw/net/stellaris_enet.c
+++ b/hw/net/stellaris_enet.c
@@ -405,7 +405,7 @@ static int stellaris_enet_init(SysBusDevice *dev)
 {
     stellaris_enet_state *s = FROM_SYSBUS(stellaris_enet_state, dev);
 
-    memory_region_init_io(&s->mmio, &stellaris_enet_ops, s, "stellaris_enet",
+    memory_region_init_io(&s->mmio, NULL, &stellaris_enet_ops, s, "stellaris_enet",
                           0x1000);
     sysbus_init_mmio(dev, &s->mmio);
     sysbus_init_irq(dev, &s->irq);
diff --git a/hw/net/vmxnet3.c b/hw/net/vmxnet3.c
index 4c575e5..23a6b07 100644
--- a/hw/net/vmxnet3.c
+++ b/hw/net/vmxnet3.c
@@ -2073,17 +2073,17 @@ static int vmxnet3_pci_init(PCIDevice *pci_dev)
 
     VMW_CBPRN("Starting init...");
 
-    memory_region_init_io(&s->bar0, &b0_ops, s,
+    memory_region_init_io(&s->bar0, NULL, &b0_ops, s,
                           "vmxnet3-b0", VMXNET3_PT_REG_SIZE);
     pci_register_bar(pci_dev, VMXNET3_BAR0_IDX,
                      PCI_BASE_ADDRESS_SPACE_MEMORY, &s->bar0);
 
-    memory_region_init_io(&s->bar1, &b1_ops, s,
+    memory_region_init_io(&s->bar1, NULL, &b1_ops, s,
                           "vmxnet3-b1", VMXNET3_VD_REG_SIZE);
     pci_register_bar(pci_dev, VMXNET3_BAR1_IDX,
                      PCI_BASE_ADDRESS_SPACE_MEMORY, &s->bar1);
 
-    memory_region_init(&s->msix_bar, "vmxnet3-msix-bar",
+    memory_region_init(&s->msix_bar, NULL, "vmxnet3-msix-bar",
                        VMXNET3_MSIX_BAR_SIZE);
     pci_register_bar(pci_dev, VMXNET3_MSIX_BAR_IDX,
                      PCI_BASE_ADDRESS_SPACE_MEMORY, &s->msix_bar);
diff --git a/hw/net/xgmac.c b/hw/net/xgmac.c
index 1d9074a..d334dc5 100644
--- a/hw/net/xgmac.c
+++ b/hw/net/xgmac.c
@@ -382,7 +382,7 @@ static int xgmac_enet_init(SysBusDevice *dev)
 {
     struct XgmacState *s = FROM_SYSBUS(typeof(*s), dev);
 
-    memory_region_init_io(&s->iomem, &enet_mem_ops, s, "xgmac", 0x1000);
+    memory_region_init_io(&s->iomem, NULL, &enet_mem_ops, s, "xgmac", 0x1000);
     sysbus_init_mmio(dev, &s->iomem);
     sysbus_init_irq(dev, &s->sbd_irq);
     sysbus_init_irq(dev, &s->pmt_irq);
diff --git a/hw/net/xilinx_axienet.c b/hw/net/xilinx_axienet.c
index 2ca1511..4a4fbd6 100644
--- a/hw/net/xilinx_axienet.c
+++ b/hw/net/xilinx_axienet.c
@@ -1001,7 +1001,7 @@ static void xilinx_enet_init(Object *obj)
 
     sysbus_init_irq(sbd, &s->irq);
 
-    memory_region_init_io(&s->iomem, &enet_ops, s, "enet", 0x40000);
+    memory_region_init_io(&s->iomem, NULL, &enet_ops, s, "enet", 0x40000);
     sysbus_init_mmio(sbd, &s->iomem);
 }
 
diff --git a/hw/net/xilinx_ethlite.c b/hw/net/xilinx_ethlite.c
index b2e3523..9d7cb8f 100644
--- a/hw/net/xilinx_ethlite.c
+++ b/hw/net/xilinx_ethlite.c
@@ -221,7 +221,7 @@ static int xilinx_ethlite_init(SysBusDevice *dev)
     sysbus_init_irq(dev, &s->irq);
     s->rxbuf = 0;
 
-    memory_region_init_io(&s->mmio, &eth_ops, s, "xlnx.xps-ethernetlite",
+    memory_region_init_io(&s->mmio, NULL, &eth_ops, s, "xlnx.xps-ethernetlite",
                                                                     R_MAX * 4);
     sysbus_init_mmio(dev, &s->mmio);
 
diff --git a/hw/nvram/ds1225y.c b/hw/nvram/ds1225y.c
index 488f1d7..1697562 100644
--- a/hw/nvram/ds1225y.c
+++ b/hw/nvram/ds1225y.c
@@ -117,7 +117,7 @@ static int nvram_sysbus_initfn(SysBusDevice *dev)
 
     s->contents = g_malloc0(s->chip_size);
 
-    memory_region_init_io(&s->iomem, &nvram_ops, s, "nvram", s->chip_size);
+    memory_region_init_io(&s->iomem, NULL, &nvram_ops, s, "nvram", s->chip_size);
     sysbus_init_mmio(dev, &s->iomem);
 
     /* Read current file */
diff --git a/hw/nvram/fw_cfg.c b/hw/nvram/fw_cfg.c
index 3c255ce..a37db77 100644
--- a/hw/nvram/fw_cfg.c
+++ b/hw/nvram/fw_cfg.c
@@ -526,14 +526,14 @@ static int fw_cfg_init1(SysBusDevice *dev)
 {
     FWCfgState *s = FROM_SYSBUS(FWCfgState, dev);
 
-    memory_region_init_io(&s->ctl_iomem, &fw_cfg_ctl_mem_ops, s,
+    memory_region_init_io(&s->ctl_iomem, NULL, &fw_cfg_ctl_mem_ops, s,
                           "fwcfg.ctl", FW_CFG_SIZE);
     sysbus_init_mmio(dev, &s->ctl_iomem);
-    memory_region_init_io(&s->data_iomem, &fw_cfg_data_mem_ops, s,
+    memory_region_init_io(&s->data_iomem, NULL, &fw_cfg_data_mem_ops, s,
                           "fwcfg.data", FW_CFG_DATA_SIZE);
     sysbus_init_mmio(dev, &s->data_iomem);
     /* In case ctl and data overlap: */
-    memory_region_init_io(&s->comb_iomem, &fw_cfg_comb_mem_ops, s,
+    memory_region_init_io(&s->comb_iomem, NULL, &fw_cfg_comb_mem_ops, s,
                           "fwcfg", FW_CFG_SIZE);
 
     if (s->ctl_iobase + 1 == s->data_iobase) {
diff --git a/hw/nvram/mac_nvram.c b/hw/nvram/mac_nvram.c
index d76a06c..c91ee58 100644
--- a/hw/nvram/mac_nvram.c
+++ b/hw/nvram/mac_nvram.c
@@ -115,7 +115,7 @@ static void macio_nvram_realizefn(DeviceState *dev, Error **errp)
 
     s->data = g_malloc0(s->size);
 
-    memory_region_init_io(&s->mem, &macio_nvram_ops, s, "macio-nvram",
+    memory_region_init_io(&s->mem, NULL, &macio_nvram_ops, s, "macio-nvram",
                           s->size << s->it_shift);
     sysbus_init_mmio(d, &s->mem);
 }
diff --git a/hw/openrisc/openrisc_sim.c b/hw/openrisc/openrisc_sim.c
index 49bab1f..924438b 100644
--- a/hw/openrisc/openrisc_sim.c
+++ b/hw/openrisc/openrisc_sim.c
@@ -115,7 +115,7 @@ static void openrisc_sim_init(QEMUMachineInitArgs *args)
     }
 
     ram = g_malloc(sizeof(*ram));
-    memory_region_init_ram(ram, "openrisc.ram", ram_size);
+    memory_region_init_ram(ram, NULL, "openrisc.ram", ram_size);
     vmstate_register_ram_global(ram);
     memory_region_add_subregion(get_system_memory(), 0, ram);
 
diff --git a/hw/pci-bridge/dec.c b/hw/pci-bridge/dec.c
index cff458b..3e84473 100644
--- a/hw/pci-bridge/dec.c
+++ b/hw/pci-bridge/dec.c
@@ -98,9 +98,9 @@ static int pci_dec_21154_device_init(SysBusDevice *dev)
 
     phb = PCI_HOST_BRIDGE(dev);
 
-    memory_region_init_io(&phb->conf_mem, &pci_host_conf_le_ops,
+    memory_region_init_io(&phb->conf_mem, NULL, &pci_host_conf_le_ops,
                           dev, "pci-conf-idx", 0x1000);
-    memory_region_init_io(&phb->data_mem, &pci_host_data_le_ops,
+    memory_region_init_io(&phb->data_mem, NULL, &pci_host_data_le_ops,
                           dev, "pci-data-idx", 0x1000);
     sysbus_init_mmio(dev, &phb->conf_mem);
     sysbus_init_mmio(dev, &phb->data_mem);
diff --git a/hw/pci-bridge/pci_bridge_dev.c b/hw/pci-bridge/pci_bridge_dev.c
index 971b432..c2660f1 100644
--- a/hw/pci-bridge/pci_bridge_dev.c
+++ b/hw/pci-bridge/pci_bridge_dev.c
@@ -46,7 +46,7 @@ static int pci_bridge_dev_initfn(PCIDevice *dev)
     if (err) {
         goto bridge_error;
     }
-    memory_region_init(&bridge_dev->bar, "shpc-bar", shpc_bar_size(dev));
+    memory_region_init(&bridge_dev->bar, NULL, "shpc-bar", shpc_bar_size(dev));
     err = shpc_init(dev, &br->sec_bus, &bridge_dev->bar, 0);
     if (err) {
         goto shpc_error;
diff --git a/hw/pci-host/apb.c b/hw/pci-host/apb.c
index e099655..7a8ce25 100644
--- a/hw/pci-host/apb.c
+++ b/hw/pci-host/apb.c
@@ -447,7 +447,7 @@ PCIBus *pci_apb_init(hwaddr special_base,
     sysbus_mmio_map(s, 2, special_base + 0x2000000ULL);
     d = FROM_SYSBUS(APBState, s);
 
-    memory_region_init(&d->pci_mmio, "pci-mmio", 0x100000000ULL);
+    memory_region_init(&d->pci_mmio, NULL, "pci-mmio", 0x100000000ULL);
     memory_region_add_subregion(get_system_memory(), mem_base, &d->pci_mmio);
 
     d->bus = pci_register_bus(&d->busdev.qdev, "pci",
@@ -525,18 +525,18 @@ static int pci_pbm_init_device(SysBusDevice *dev)
     s->pci_irq_in = 0ULL;
 
     /* apb_config */
-    memory_region_init_io(&s->apb_config, &apb_config_ops, s, "apb-config",
+    memory_region_init_io(&s->apb_config, NULL, &apb_config_ops, s, "apb-config",
                           0x10000);
     /* at region 0 */
     sysbus_init_mmio(dev, &s->apb_config);
 
-    memory_region_init_io(&s->pci_config, &pci_config_ops, s, "apb-pci-config",
+    memory_region_init_io(&s->pci_config, NULL, &pci_config_ops, s, "apb-pci-config",
                           0x1000000);
     /* at region 1 */
     sysbus_init_mmio(dev, &s->pci_config);
 
     /* pci_ioport */
-    memory_region_init_io(&s->pci_ioport, &pci_ioport_ops, s,
+    memory_region_init_io(&s->pci_ioport, NULL, &pci_ioport_ops, s,
                           "apb-pci-ioport", 0x10000);
     /* at region 2 */
     sysbus_init_mmio(dev, &s->pci_ioport);
diff --git a/hw/pci-host/bonito.c b/hw/pci-host/bonito.c
index 974150b..ae00775 100644
--- a/hw/pci-host/bonito.c
+++ b/hw/pci-host/bonito.c
@@ -722,29 +722,29 @@ static int bonito_initfn(PCIDevice *dev)
     pci_config_set_prog_interface(dev->config, 0x00);
 
     /* set the north bridge register mapping */
-    memory_region_init_io(&s->iomem, &bonito_ops, s,
+    memory_region_init_io(&s->iomem, NULL, &bonito_ops, s,
                           "north-bridge-register", BONITO_INTERNAL_REG_SIZE);
     sysbus_init_mmio(sysbus, &s->iomem);
     sysbus_mmio_map(sysbus, 0, BONITO_INTERNAL_REG_BASE);
 
     /* set the north bridge pci configure  mapping */
-    memory_region_init_io(&phb->conf_mem, &bonito_pciconf_ops, s,
+    memory_region_init_io(&phb->conf_mem, NULL, &bonito_pciconf_ops, s,
                           "north-bridge-pci-config", BONITO_PCICONFIG_SIZE);
     sysbus_init_mmio(sysbus, &phb->conf_mem);
     sysbus_mmio_map(sysbus, 1, BONITO_PCICONFIG_BASE);
 
     /* set the south bridge pci configure  mapping */
-    memory_region_init_io(&phb->data_mem, &bonito_spciconf_ops, s,
+    memory_region_init_io(&phb->data_mem, NULL, &bonito_spciconf_ops, s,
                           "south-bridge-pci-config", BONITO_SPCICONFIG_SIZE);
     sysbus_init_mmio(sysbus, &phb->data_mem);
     sysbus_mmio_map(sysbus, 2, BONITO_SPCICONFIG_BASE);
 
-    memory_region_init_io(&s->iomem_ldma, &bonito_ldma_ops, s,
+    memory_region_init_io(&s->iomem_ldma, NULL, &bonito_ldma_ops, s,
                           "ldma", 0x100);
     sysbus_init_mmio(sysbus, &s->iomem_ldma);
     sysbus_mmio_map(sysbus, 3, 0xbfe00200);
 
-    memory_region_init_io(&s->iomem_cop, &bonito_cop_ops, s,
+    memory_region_init_io(&s->iomem_cop, NULL, &bonito_cop_ops, s,
                           "cop", 0x100);
     sysbus_init_mmio(sysbus, &s->iomem_cop);
     sysbus_mmio_map(sysbus, 4, 0xbfe00300);
diff --git a/hw/pci-host/grackle.c b/hw/pci-host/grackle.c
index 69344d9..da0fedb 100644
--- a/hw/pci-host/grackle.c
+++ b/hw/pci-host/grackle.c
@@ -76,8 +76,8 @@ PCIBus *pci_grackle_init(uint32_t base, qemu_irq *pic,
     phb = PCI_HOST_BRIDGE(dev);
     d = GRACKLE_PCI_HOST_BRIDGE(dev);
 
-    memory_region_init(&d->pci_mmio, "pci-mmio", 0x100000000ULL);
-    memory_region_init_alias(&d->pci_hole, "pci-hole", &d->pci_mmio,
+    memory_region_init(&d->pci_mmio, NULL, "pci-mmio", 0x100000000ULL);
+    memory_region_init_alias(&d->pci_hole, NULL, "pci-hole", &d->pci_mmio,
                              0x80000000ULL, 0x7e000000ULL);
     memory_region_add_subregion(address_space_mem, 0x80000000ULL,
                                 &d->pci_hole);
@@ -104,9 +104,9 @@ static int pci_grackle_init_device(SysBusDevice *dev)
 
     phb = PCI_HOST_BRIDGE(dev);
 
-    memory_region_init_io(&phb->conf_mem, &pci_host_conf_le_ops,
+    memory_region_init_io(&phb->conf_mem, NULL, &pci_host_conf_le_ops,
                           dev, "pci-conf-idx", 0x1000);
-    memory_region_init_io(&phb->data_mem, &pci_host_data_le_ops,
+    memory_region_init_io(&phb->data_mem, NULL, &pci_host_data_le_ops,
                           dev, "pci-data-idx", 0x1000);
     sysbus_init_mmio(dev, &phb->conf_mem);
     sysbus_init_mmio(dev, &phb->data_mem);
diff --git a/hw/pci-host/pam.c b/hw/pci-host/pam.c
index 7181bd6..ec935f440 100644
--- a/hw/pci-host/pam.c
+++ b/hw/pci-host/pam.c
@@ -56,17 +56,17 @@ void init_pam(MemoryRegion *ram_memory, MemoryRegion *system_memory,
     int i;
 
     /* RAM */
-    memory_region_init_alias(&mem->alias[3], "pam-ram", ram_memory,
+    memory_region_init_alias(&mem->alias[3], NULL, "pam-ram", ram_memory,
                              start, size);
     /* ROM (XXX: not quite correct) */
-    memory_region_init_alias(&mem->alias[1], "pam-rom", ram_memory,
+    memory_region_init_alias(&mem->alias[1], NULL, "pam-rom", ram_memory,
                              start, size);
     memory_region_set_readonly(&mem->alias[1], true);
 
     /* XXX: should distinguish read/write cases */
-    memory_region_init_alias(&mem->alias[0], "pam-pci", pci_address_space,
+    memory_region_init_alias(&mem->alias[0], NULL, "pam-pci", pci_address_space,
                              start, size);
-    memory_region_init_alias(&mem->alias[2], "pam-pci", pci_address_space,
+    memory_region_init_alias(&mem->alias[2], NULL, "pam-pci", pci_address_space,
                              start, size);
 
     for (i = 0; i < 4; ++i) {
diff --git a/hw/pci-host/piix.c b/hw/pci-host/piix.c
index f9e68c3..4d77b1e 100644
--- a/hw/pci-host/piix.c
+++ b/hw/pci-host/piix.c
@@ -201,12 +201,12 @@ static int i440fx_pcihost_initfn(SysBusDevice *dev)
 {
     PCIHostState *s = PCI_HOST_BRIDGE(dev);
 
-    memory_region_init_io(&s->conf_mem, &pci_host_conf_le_ops, s,
+    memory_region_init_io(&s->conf_mem, NULL, &pci_host_conf_le_ops, s,
                           "pci-conf-idx", 4);
     sysbus_add_io(dev, 0xcf8, &s->conf_mem);
     sysbus_init_ioports(&s->busdev, 0xcf8, 4);
 
-    memory_region_init_io(&s->data_mem, &pci_host_data_le_ops, s,
+    memory_region_init_io(&s->data_mem, NULL, &pci_host_data_le_ops, s,
                           "pci-conf-data", 4);
     sysbus_add_io(dev, 0xcfc, &s->data_mem);
     sysbus_init_ioports(&s->busdev, 0xcfc, 4);
@@ -260,17 +260,17 @@ static PCIBus *i440fx_common_init(const char *device_name,
     f->system_memory = address_space_mem;
     f->pci_address_space = pci_address_space;
     f->ram_memory = ram_memory;
-    memory_region_init_alias(&f->pci_hole, "pci-hole", f->pci_address_space,
+    memory_region_init_alias(&f->pci_hole, NULL, "pci-hole", f->pci_address_space,
                              pci_hole_start, pci_hole_size);
     memory_region_add_subregion(f->system_memory, pci_hole_start, &f->pci_hole);
-    memory_region_init_alias(&f->pci_hole_64bit, "pci-hole64",
+    memory_region_init_alias(&f->pci_hole_64bit, NULL, "pci-hole64",
                              f->pci_address_space,
                              pci_hole64_start, pci_hole64_size);
     if (pci_hole64_size) {
         memory_region_add_subregion(f->system_memory, pci_hole64_start,
                                     &f->pci_hole_64bit);
     }
-    memory_region_init_alias(&f->smram_region, "smram-region",
+    memory_region_init_alias(&f->smram_region, NULL, "smram-region",
                              f->pci_address_space, 0xa0000, 0x20000);
     memory_region_add_subregion_overlap(f->system_memory, 0xa0000,
                                         &f->smram_region, 1);
@@ -549,7 +549,7 @@ static int piix3_initfn(PCIDevice *dev)
 
     isa_bus_new(DEVICE(d), pci_address_space_io(dev));
 
-    memory_region_init_io(&d->rcr_mem, &rcr_ops, d, "piix3-reset-control", 1);
+    memory_region_init_io(&d->rcr_mem, NULL, &rcr_ops, d, "piix3-reset-control", 1);
     memory_region_add_subregion_overlap(pci_address_space_io(dev), RCR_IOPORT,
                                         &d->rcr_mem, 1);
 
diff --git a/hw/pci-host/ppce500.c b/hw/pci-host/ppce500.c
index 5e7ad94..7d8c59b 100644
--- a/hw/pci-host/ppce500.c
+++ b/hw/pci-host/ppce500.c
@@ -330,7 +330,7 @@ static int e500_pcihost_bridge_initfn(PCIDevice *d)
         (d->config[PCI_HEADER_TYPE] & PCI_HEADER_TYPE_MULTI_FUNCTION) |
         PCI_HEADER_TYPE_BRIDGE;
 
-    memory_region_init_alias(&b->bar0, "e500-pci-bar0", &ccsr->ccsr_space,
+    memory_region_init_alias(&b->bar0, NULL, "e500-pci-bar0", &ccsr->ccsr_space,
                              0, int128_get64(ccsr->ccsr_space.size));
     pci_register_bar(d, 0, PCI_BASE_ADDRESS_SPACE_MEMORY, &b->bar0);
 
@@ -352,7 +352,7 @@ static int e500_pcihost_initfn(SysBusDevice *dev)
         sysbus_init_irq(dev, &s->irq[i]);
     }
 
-    memory_region_init(&s->pio, "pci-pio", PCIE500_PCI_IOLEN);
+    memory_region_init(&s->pio, NULL, "pci-pio", PCIE500_PCI_IOLEN);
 
     b = pci_register_bus(DEVICE(dev), NULL, mpc85xx_pci_set_irq,
                          mpc85xx_pci_map_irq, s->irq, address_space_mem,
@@ -361,12 +361,12 @@ static int e500_pcihost_initfn(SysBusDevice *dev)
 
     pci_create_simple(b, 0, "e500-host-bridge");
 
-    memory_region_init(&s->container, "pci-container", PCIE500_ALL_SIZE);
-    memory_region_init_io(&h->conf_mem, &pci_host_conf_be_ops, h,
+    memory_region_init(&s->container, NULL, "pci-container", PCIE500_ALL_SIZE);
+    memory_region_init_io(&h->conf_mem, NULL, &pci_host_conf_be_ops, h,
                           "pci-conf-idx", 4);
-    memory_region_init_io(&h->data_mem, &pci_host_data_le_ops, h,
+    memory_region_init_io(&h->data_mem, NULL, &pci_host_data_le_ops, h,
                           "pci-conf-data", 4);
-    memory_region_init_io(&s->iomem, &e500_pci_reg_ops, s,
+    memory_region_init_io(&s->iomem, NULL, &e500_pci_reg_ops, s,
                           "pci.reg", PCIE500_REG_SIZE);
     memory_region_add_subregion(&s->container, PCIE500_CFGADDR, &h->conf_mem);
     memory_region_add_subregion(&s->container, PCIE500_CFGDATA, &h->data_mem);
diff --git a/hw/pci-host/prep.c b/hw/pci-host/prep.c
index 6130253..024cd51 100644
--- a/hw/pci-host/prep.c
+++ b/hw/pci-host/prep.c
@@ -125,20 +125,20 @@ static void raven_pcihost_realizefn(DeviceState *d, Error **errp)
 
     pci_bus_irqs(&s->pci_bus, prep_set_irq, prep_map_irq, s->irq, 4);
 
-    memory_region_init_io(&h->conf_mem, &pci_host_conf_be_ops, s,
+    memory_region_init_io(&h->conf_mem, NULL, &pci_host_conf_be_ops, s,
                           "pci-conf-idx", 1);
     sysbus_add_io(dev, 0xcf8, &h->conf_mem);
     sysbus_init_ioports(&h->busdev, 0xcf8, 1);
 
-    memory_region_init_io(&h->data_mem, &pci_host_data_be_ops, s,
+    memory_region_init_io(&h->data_mem, NULL, &pci_host_data_be_ops, s,
                           "pci-conf-data", 1);
     sysbus_add_io(dev, 0xcfc, &h->data_mem);
     sysbus_init_ioports(&h->busdev, 0xcfc, 1);
 
-    memory_region_init_io(&h->mmcfg, &PPC_PCIIO_ops, s, "pciio", 0x00400000);
+    memory_region_init_io(&h->mmcfg, NULL, &PPC_PCIIO_ops, s, "pciio", 0x00400000);
     memory_region_add_subregion(address_space_mem, 0x80800000, &h->mmcfg);
 
-    memory_region_init_io(&s->intack, &PPC_intack_ops, s, "pci-intack", 1);
+    memory_region_init_io(&s->intack, NULL, &PPC_intack_ops, s, "pci-intack", 1);
     memory_region_add_subregion(address_space_mem, 0xbffffff0, &s->intack);
 
     /* TODO Remove once realize propagates to child devices. */
diff --git a/hw/pci-host/q35.c b/hw/pci-host/q35.c
index 24df6b5..70e7d8b 100644
--- a/hw/pci-host/q35.c
+++ b/hw/pci-host/q35.c
@@ -40,12 +40,12 @@ static int q35_host_init(SysBusDevice *dev)
     PCIHostState *pci = FROM_SYSBUS(PCIHostState, dev);
     Q35PCIHost *s = Q35_HOST_DEVICE(&dev->qdev);
 
-    memory_region_init_io(&pci->conf_mem, &pci_host_conf_le_ops, pci,
+    memory_region_init_io(&pci->conf_mem, NULL, &pci_host_conf_le_ops, pci,
                           "pci-conf-idx", 4);
     sysbus_add_io(dev, MCH_HOST_BRIDGE_CONFIG_ADDR, &pci->conf_mem);
     sysbus_init_ioports(&pci->busdev, MCH_HOST_BRIDGE_CONFIG_ADDR, 4);
 
-    memory_region_init_io(&pci->data_mem, &pci_host_data_le_ops, pci,
+    memory_region_init_io(&pci->data_mem, NULL, &pci_host_data_le_ops, pci,
                           "pci-conf-data", 4);
     sysbus_add_io(dev, MCH_HOST_BRIDGE_CONFIG_DATA, &pci->data_mem);
     sysbus_init_ioports(&pci->busdev, MCH_HOST_BRIDGE_CONFIG_DATA, 4);
@@ -245,7 +245,7 @@ static int mch_init(PCIDevice *d)
     MCHPCIState *mch = MCH_PCI_DEVICE(d);
 
     /* setup pci memory regions */
-    memory_region_init_alias(&mch->pci_hole, "pci-hole",
+    memory_region_init_alias(&mch->pci_hole, NULL, "pci-hole",
                              mch->pci_address_space,
                              mch->below_4g_mem_size,
                              0x100000000ULL - mch->below_4g_mem_size);
@@ -253,7 +253,7 @@ static int mch_init(PCIDevice *d)
                                 &mch->pci_hole);
     pci_hole64_size = (sizeof(hwaddr) == 4 ? 0 :
                        ((uint64_t)1 << 62));
-    memory_region_init_alias(&mch->pci_hole_64bit, "pci-hole64",
+    memory_region_init_alias(&mch->pci_hole_64bit, NULL, "pci-hole64",
                              mch->pci_address_space,
                              0x100000000ULL + mch->above_4g_mem_size,
                              pci_hole64_size);
@@ -264,7 +264,7 @@ static int mch_init(PCIDevice *d)
     }
     /* smram */
     cpu_smm_register(&mch_set_smm, mch);
-    memory_region_init_alias(&mch->smram_region, "smram-region",
+    memory_region_init_alias(&mch->smram_region, NULL, "smram-region",
                              mch->pci_address_space, 0xa0000, 0x20000);
     memory_region_add_subregion_overlap(mch->system_memory, 0xa0000,
                                         &mch->smram_region, 1);
diff --git a/hw/pci-host/uninorth.c b/hw/pci-host/uninorth.c
index fff235d..b72659d 100644
--- a/hw/pci-host/uninorth.c
+++ b/hw/pci-host/uninorth.c
@@ -152,9 +152,9 @@ static int pci_unin_main_init_device(SysBusDevice *dev)
     /* Uninorth main bus */
     h = PCI_HOST_BRIDGE(dev);
 
-    memory_region_init_io(&h->conf_mem, &pci_host_conf_le_ops,
+    memory_region_init_io(&h->conf_mem, NULL, &pci_host_conf_le_ops,
                           dev, "pci-conf-idx", 0x1000);
-    memory_region_init_io(&h->data_mem, &unin_data_ops, dev,
+    memory_region_init_io(&h->data_mem, NULL, &unin_data_ops, dev,
                           "pci-conf-data", 0x1000);
     sysbus_init_mmio(dev, &h->conf_mem);
     sysbus_init_mmio(dev, &h->data_mem);
@@ -170,9 +170,9 @@ static int pci_u3_agp_init_device(SysBusDevice *dev)
     /* Uninorth U3 AGP bus */
     h = PCI_HOST_BRIDGE(dev);
 
-    memory_region_init_io(&h->conf_mem, &pci_host_conf_le_ops,
+    memory_region_init_io(&h->conf_mem, NULL, &pci_host_conf_le_ops,
                           dev, "pci-conf-idx", 0x1000);
-    memory_region_init_io(&h->data_mem, &unin_data_ops, dev,
+    memory_region_init_io(&h->data_mem, NULL, &unin_data_ops, dev,
                           "pci-conf-data", 0x1000);
     sysbus_init_mmio(dev, &h->conf_mem);
     sysbus_init_mmio(dev, &h->data_mem);
@@ -187,9 +187,9 @@ static int pci_unin_agp_init_device(SysBusDevice *dev)
     /* Uninorth AGP bus */
     h = PCI_HOST_BRIDGE(dev);
 
-    memory_region_init_io(&h->conf_mem, &pci_host_conf_le_ops,
+    memory_region_init_io(&h->conf_mem, NULL, &pci_host_conf_le_ops,
                           dev, "pci-conf-idx", 0x1000);
-    memory_region_init_io(&h->data_mem, &pci_host_data_le_ops,
+    memory_region_init_io(&h->data_mem, NULL, &pci_host_data_le_ops,
                           dev, "pci-conf-data", 0x1000);
     sysbus_init_mmio(dev, &h->conf_mem);
     sysbus_init_mmio(dev, &h->data_mem);
@@ -203,9 +203,9 @@ static int pci_unin_internal_init_device(SysBusDevice *dev)
     /* Uninorth internal bus */
     h = PCI_HOST_BRIDGE(dev);
 
-    memory_region_init_io(&h->conf_mem, &pci_host_conf_le_ops,
+    memory_region_init_io(&h->conf_mem, NULL, &pci_host_conf_le_ops,
                           dev, "pci-conf-idx", 0x1000);
-    memory_region_init_io(&h->data_mem, &pci_host_data_le_ops,
+    memory_region_init_io(&h->data_mem, NULL, &pci_host_data_le_ops,
                           dev, "pci-conf-data", 0x1000);
     sysbus_init_mmio(dev, &h->conf_mem);
     sysbus_init_mmio(dev, &h->data_mem);
@@ -228,8 +228,8 @@ PCIBus *pci_pmac_init(qemu_irq *pic,
     s = SYS_BUS_DEVICE(dev);
     h = PCI_HOST_BRIDGE(s);
     d = UNI_NORTH_PCI_HOST_BRIDGE(dev);
-    memory_region_init(&d->pci_mmio, "pci-mmio", 0x100000000ULL);
-    memory_region_init_alias(&d->pci_hole, "pci-hole", &d->pci_mmio,
+    memory_region_init(&d->pci_mmio, NULL, "pci-mmio", 0x100000000ULL);
+    memory_region_init_alias(&d->pci_hole, NULL, "pci-hole", &d->pci_mmio,
                              0x80000000ULL, 0x70000000ULL);
     memory_region_add_subregion(address_space_mem, 0x80000000ULL,
                                 &d->pci_hole);
@@ -294,8 +294,8 @@ PCIBus *pci_pmac_u3_init(qemu_irq *pic,
     h = PCI_HOST_BRIDGE(dev);
     d = U3_AGP_HOST_BRIDGE(dev);
 
-    memory_region_init(&d->pci_mmio, "pci-mmio", 0x100000000ULL);
-    memory_region_init_alias(&d->pci_hole, "pci-hole", &d->pci_mmio,
+    memory_region_init(&d->pci_mmio, NULL, "pci-mmio", 0x100000000ULL);
+    memory_region_init_alias(&d->pci_hole, NULL, "pci-hole", &d->pci_mmio,
                              0x80000000ULL, 0x70000000ULL);
     memory_region_add_subregion(address_space_mem, 0x80000000ULL,
                                 &d->pci_hole);
diff --git a/hw/pci-host/versatile.c b/hw/pci-host/versatile.c
index 2f996d9..f7df274 100644
--- a/hw/pci-host/versatile.c
+++ b/hw/pci-host/versatile.c
@@ -381,8 +381,8 @@ static void pci_vpb_init(Object *obj)
     PCIHostState *h = PCI_HOST_BRIDGE(obj);
     PCIVPBState *s = PCI_VPB(obj);
 
-    memory_region_init(&s->pci_io_space, "pci_io", 1ULL << 32);
-    memory_region_init(&s->pci_mem_space, "pci_mem", 1ULL << 32);
+    memory_region_init(&s->pci_io_space, NULL, "pci_io", 1ULL << 32);
+    memory_region_init(&s->pci_mem_space, NULL, "pci_mem", 1ULL << 32);
 
     pci_bus_new_inplace(&s->pci_bus, DEVICE(obj), "pci",
                         &s->pci_mem_space, &s->pci_io_space,
@@ -424,20 +424,20 @@ static void pci_vpb_realize(DeviceState *dev, Error **errp)
      * 3 : PCI IO window
      * 4..6 : PCI memory windows
      */
-    memory_region_init_io(&s->controlregs, &pci_vpb_reg_ops, s, "pci-vpb-regs",
+    memory_region_init_io(&s->controlregs, NULL, &pci_vpb_reg_ops, s, "pci-vpb-regs",
                           0x1000);
     sysbus_init_mmio(sbd, &s->controlregs);
-    memory_region_init_io(&s->mem_config, &pci_vpb_config_ops, s,
+    memory_region_init_io(&s->mem_config, NULL, &pci_vpb_config_ops, s,
                           "pci-vpb-selfconfig", 0x1000000);
     sysbus_init_mmio(sbd, &s->mem_config);
-    memory_region_init_io(&s->mem_config2, &pci_vpb_config_ops, s,
+    memory_region_init_io(&s->mem_config2, NULL, &pci_vpb_config_ops, s,
                           "pci-vpb-config", 0x1000000);
     sysbus_init_mmio(sbd, &s->mem_config2);
 
     /* The window into I/O space is always into a fixed base address;
      * its size is the same for both realview and versatile.
      */
-    memory_region_init_alias(&s->pci_io_window, "pci-vbp-io-window",
+    memory_region_init_alias(&s->pci_io_window, NULL, "pci-vbp-io-window",
                              &s->pci_io_space, 0, 0x100000);
 
     sysbus_init_mmio(sbd, &s->pci_io_space);
@@ -447,7 +447,7 @@ static void pci_vpb_realize(DeviceState *dev, Error **errp)
      * offsets are guest controllable via the IMAP registers.
      */
     for (i = 0; i < 3; i++) {
-        memory_region_init_alias(&s->pci_mem_window[i], "pci-vbp-window",
+        memory_region_init_alias(&s->pci_mem_window[i], NULL, "pci-vbp-window",
                                  &s->pci_mem_space, 0, s->mem_win_size[i]);
         sysbus_init_mmio(sbd, &s->pci_mem_window[i]);
     }
diff --git a/hw/pci/msix.c b/hw/pci/msix.c
index 6da75ec..83dfc7a 100644
--- a/hw/pci/msix.c
+++ b/hw/pci/msix.c
@@ -280,10 +280,10 @@ int msix_init(struct PCIDevice *dev, unsigned short nentries,
 
     msix_mask_all(dev, nentries);
 
-    memory_region_init_io(&dev->msix_table_mmio, &msix_table_mmio_ops, dev,
+    memory_region_init_io(&dev->msix_table_mmio, NULL, &msix_table_mmio_ops, dev,
                           "msix-table", table_size);
     memory_region_add_subregion(table_bar, table_offset, &dev->msix_table_mmio);
-    memory_region_init_io(&dev->msix_pba_mmio, &msix_pba_mmio_ops, dev,
+    memory_region_init_io(&dev->msix_pba_mmio, NULL, &msix_pba_mmio_ops, dev,
                           "msix-pba", pba_size);
     memory_region_add_subregion(pba_bar, pba_offset, &dev->msix_pba_mmio);
 
@@ -311,7 +311,7 @@ int msix_init_exclusive_bar(PCIDevice *dev, unsigned short nentries,
     }
 
     name = g_strdup_printf("%s-msix", dev->name);
-    memory_region_init(&dev->msix_exclusive_bar, name, MSIX_EXCLUSIVE_BAR_SIZE);
+    memory_region_init(&dev->msix_exclusive_bar, NULL, name, MSIX_EXCLUSIVE_BAR_SIZE);
     g_free(name);
 
     ret = msix_init(dev, nentries, &dev->msix_exclusive_bar, bar_nr,
diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index 61b681a..a29a385 100644
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -811,7 +811,7 @@ static PCIDevice *do_pci_register_device(PCIDevice *pci_dev, PCIBus *bus,
         dma_as = &address_space_memory;
     }
 
-    memory_region_init_alias(&pci_dev->bus_master_enable_region, "bus master",
+    memory_region_init_alias(&pci_dev->bus_master_enable_region, NULL, "bus master",
                              dma_as->root, 0, memory_region_size(dma_as->root));
     memory_region_set_enabled(&pci_dev->bus_master_enable_region, false);
     address_space_init(&pci_dev->bus_master_as, &pci_dev->bus_master_enable_region,
@@ -1945,7 +1945,7 @@ static int pci_add_option_rom(PCIDevice *pdev, bool is_default_rom)
         snprintf(name, sizeof(name), "%s.rom", object_get_typename(OBJECT(pdev)));
     }
     pdev->has_rom = true;
-    memory_region_init_ram(&pdev->rom, name, size);
+    memory_region_init_ram(&pdev->rom, NULL, name, size);
     vmstate_register_ram(&pdev->rom, &pdev->qdev);
     ptr = memory_region_get_ram_ptr(&pdev->rom);
     load_image(path, ptr);
diff --git a/hw/pci/pci_bridge.c b/hw/pci/pci_bridge.c
index 24be6c5..28ae65e 100644
--- a/hw/pci/pci_bridge.c
+++ b/hw/pci/pci_bridge.c
@@ -147,7 +147,7 @@ static void pci_bridge_init_alias(PCIBridge *bridge, MemoryRegion *alias,
      * Apparently no way to do this with existing memory APIs. */
     pcibus_t size = enabled && limit >= base ? limit + 1 - base : 0;
 
-    memory_region_init_alias(alias, name, space, base, size);
+    memory_region_init_alias(alias, NULL, name, space, base, size);
     memory_region_add_subregion_overlap(parent_space, base, alias, 1);
 }
 
@@ -156,13 +156,13 @@ static void pci_bridge_init_vga_aliases(PCIBridge *br, PCIBus *parent,
 {
     uint16_t brctl = pci_get_word(br->dev.config + PCI_BRIDGE_CONTROL);
 
-    memory_region_init_alias(&alias_vga[QEMU_PCI_VGA_IO_LO],
+    memory_region_init_alias(&alias_vga[QEMU_PCI_VGA_IO_LO], NULL,
                              "pci_bridge_vga_io_lo", &br->address_space_io,
                              QEMU_PCI_VGA_IO_LO_BASE, QEMU_PCI_VGA_IO_LO_SIZE);
-    memory_region_init_alias(&alias_vga[QEMU_PCI_VGA_IO_HI],
+    memory_region_init_alias(&alias_vga[QEMU_PCI_VGA_IO_HI], NULL,
                              "pci_bridge_vga_io_hi", &br->address_space_io,
                              QEMU_PCI_VGA_IO_HI_BASE, QEMU_PCI_VGA_IO_HI_SIZE);
-    memory_region_init_alias(&alias_vga[QEMU_PCI_VGA_MEM],
+    memory_region_init_alias(&alias_vga[QEMU_PCI_VGA_MEM], NULL,
                              "pci_bridge_vga_mem", &br->address_space_mem,
                              QEMU_PCI_VGA_MEM_BASE, QEMU_PCI_VGA_MEM_SIZE);
 
@@ -367,9 +367,9 @@ int pci_bridge_initfn(PCIDevice *dev, const char *typename)
     sec_bus->parent_dev = dev;
     sec_bus->map_irq = br->map_irq ? br->map_irq : pci_swizzle_map_irq_fn;
     sec_bus->address_space_mem = &br->address_space_mem;
-    memory_region_init(&br->address_space_mem, "pci_bridge_pci", INT64_MAX);
+    memory_region_init(&br->address_space_mem, NULL, "pci_bridge_pci", INT64_MAX);
     sec_bus->address_space_io = &br->address_space_io;
-    memory_region_init(&br->address_space_io, "pci_bridge_io", 65536);
+    memory_region_init(&br->address_space_io, NULL, "pci_bridge_io", 65536);
     br->windows = pci_bridge_region_init(br);
     QLIST_INIT(&sec_bus->child);
     QLIST_INSERT_HEAD(&parent->child, sec_bus, sibling);
diff --git a/hw/pci/pcie_host.c b/hw/pci/pcie_host.c
index b2d942b..26f2007 100644
--- a/hw/pci/pcie_host.c
+++ b/hw/pci/pcie_host.c
@@ -130,7 +130,7 @@ void pcie_host_mmcfg_map(PCIExpressHost *e, hwaddr addr,
     assert(size >= PCIE_MMCFG_SIZE_MIN);
     assert(size <= PCIE_MMCFG_SIZE_MAX);
     e->size = size;
-    memory_region_init_io(&e->mmio, &pcie_mmcfg_ops, e, "pcie-mmcfg", e->size);
+    memory_region_init_io(&e->mmio, NULL, &pcie_mmcfg_ops, e, "pcie-mmcfg", e->size);
     e->base_addr = addr;
     memory_region_add_subregion(get_system_memory(), e->base_addr, &e->mmio);
 }
diff --git a/hw/pci/shpc.c b/hw/pci/shpc.c
index d35c2ee..c4eae07 100644
--- a/hw/pci/shpc.c
+++ b/hw/pci/shpc.c
@@ -612,7 +612,7 @@ int shpc_init(PCIDevice *d, PCIBus *sec_bus, MemoryRegion *bar, unsigned offset)
     }
 
     /* TODO: init cmask */
-    memory_region_init_io(&shpc->mmio, &shpc_mmio_ops, d, "shpc-mmio",
+    memory_region_init_io(&shpc->mmio, NULL, &shpc_mmio_ops, d, "shpc-mmio",
                           SHPC_SIZEOF(d));
     shpc_cap_update_dword(d);
     memory_region_add_subregion(bar, offset, &shpc->mmio);
diff --git a/hw/ppc/e500.c b/hw/ppc/e500.c
index c9ae512..4e902b8 100644
--- a/hw/ppc/e500.c
+++ b/hw/ppc/e500.c
@@ -550,7 +550,7 @@ void ppce500_init(PPCE500Params *params)
     params->ram_size = ram_size;
 
     /* Register Memory */
-    memory_region_init_ram(ram, "mpc8544ds.ram", ram_size);
+    memory_region_init_ram(ram, NULL, "mpc8544ds.ram", ram_size);
     vmstate_register_ram_global(ram);
     memory_region_add_subregion(address_space_mem, 0, ram);
 
@@ -702,7 +702,7 @@ static int e500_ccsr_initfn(SysBusDevice *dev)
     PPCE500CCSRState *ccsr;
 
     ccsr = CCSR(dev);
-    memory_region_init(&ccsr->ccsr_space, "e500-ccsr",
+    memory_region_init(&ccsr->ccsr_space, NULL, "e500-ccsr",
                        MPC8544_CCSRBAR_SIZE);
     return 0;
 }
diff --git a/hw/ppc/mac_newworld.c b/hw/ppc/mac_newworld.c
index ce44e95..28d0f7e 100644
--- a/hw/ppc/mac_newworld.c
+++ b/hw/ppc/mac_newworld.c
@@ -186,12 +186,12 @@ static void ppc_core99_init(QEMUMachineInitArgs *args)
     }
 
     /* allocate RAM */
-    memory_region_init_ram(ram, "ppc_core99.ram", ram_size);
+    memory_region_init_ram(ram, NULL, "ppc_core99.ram", ram_size);
     vmstate_register_ram_global(ram);
     memory_region_add_subregion(get_system_memory(), 0, ram);
 
     /* allocate and load BIOS */
-    memory_region_init_ram(bios, "ppc_core99.bios", BIOS_SIZE);
+    memory_region_init_ram(bios, NULL, "ppc_core99.bios", BIOS_SIZE);
     vmstate_register_ram_global(bios);
     if (bios_name == NULL)
         bios_name = PROM_FILENAME;
@@ -280,7 +280,7 @@ static void ppc_core99_init(QEMUMachineInitArgs *args)
     isa_mmio_init(0xf2000000, 0x00800000);
 
     /* UniN init */
-    memory_region_init_io(unin_memory, &unin_ops, NULL, "unin", 0x1000);
+    memory_region_init_io(unin_memory, NULL, &unin_ops, NULL, "unin", 0x1000);
     memory_region_add_subregion(get_system_memory(), 0xf8000000, unin_memory);
 
     openpic_irqs = g_malloc0(smp_cpus * sizeof(qemu_irq *));
@@ -358,7 +358,7 @@ static void ppc_core99_init(QEMUMachineInitArgs *args)
 
     escc_mem = escc_init(0, pic[0x25], pic[0x24],
                          serial_hds[0], serial_hds[1], ESCC_CLOCK, 4);
-    memory_region_init_alias(escc_bar, "escc-bar",
+    memory_region_init_alias(escc_bar, NULL, "escc-bar",
                              escc_mem, 0, memory_region_size(escc_mem));
 
     for(i = 0; i < nb_nics; i++)
diff --git a/hw/ppc/mac_oldworld.c b/hw/ppc/mac_oldworld.c
index 3acca94..313baf2 100644
--- a/hw/ppc/mac_oldworld.c
+++ b/hw/ppc/mac_oldworld.c
@@ -126,12 +126,12 @@ static void ppc_heathrow_init(QEMUMachineInitArgs *args)
         exit(1);
     }
 
-    memory_region_init_ram(ram, "ppc_heathrow.ram", ram_size);
+    memory_region_init_ram(ram, NULL, "ppc_heathrow.ram", ram_size);
     vmstate_register_ram_global(ram);
     memory_region_add_subregion(sysmem, 0, ram);
 
     /* allocate and load BIOS */
-    memory_region_init_ram(bios, "ppc_heathrow.bios", BIOS_SIZE);
+    memory_region_init_ram(bios, NULL, "ppc_heathrow.bios", BIOS_SIZE);
     vmstate_register_ram_global(bios);
     if (bios_name == NULL)
         bios_name = PROM_FILENAME;
@@ -255,7 +255,7 @@ static void ppc_heathrow_init(QEMUMachineInitArgs *args)
 
     escc_mem = escc_init(0, pic[0x0f], pic[0x10], serial_hds[0],
                                serial_hds[1], ESCC_CLOCK, 4);
-    memory_region_init_alias(escc_bar, "escc-bar",
+    memory_region_init_alias(escc_bar, NULL, "escc-bar",
                              escc_mem, 0, memory_region_size(escc_mem));
 
     for(i = 0; i < nb_nics; i++)
diff --git a/hw/ppc/mpc8544_guts.c b/hw/ppc/mpc8544_guts.c
index 193beab..9d34fd5 100644
--- a/hw/ppc/mpc8544_guts.c
+++ b/hw/ppc/mpc8544_guts.c
@@ -114,7 +114,7 @@ static int mpc8544_guts_initfn(SysBusDevice *dev)
 
     s = FROM_SYSBUS(GutsState, SYS_BUS_DEVICE(dev));
 
-    memory_region_init_io(&s->iomem, &mpc8544_guts_ops, s,
+    memory_region_init_io(&s->iomem, NULL, &mpc8544_guts_ops, s,
                           "mpc6544.guts", MPC8544_GUTS_MMIO_SIZE);
     sysbus_init_mmio(dev, &s->iomem);
 
diff --git a/hw/ppc/ppc405_boards.c b/hw/ppc/ppc405_boards.c
index f0c7ee9..f74e5e5 100644
--- a/hw/ppc/ppc405_boards.c
+++ b/hw/ppc/ppc405_boards.c
@@ -164,7 +164,7 @@ static void ref405ep_fpga_init(MemoryRegion *sysmem, uint32_t base)
     MemoryRegion *fpga_memory = g_new(MemoryRegion, 1);
 
     fpga = g_malloc0(sizeof(ref405ep_fpga_t));
-    memory_region_init_io(fpga_memory, &ref405ep_fpga_ops, fpga,
+    memory_region_init_io(fpga_memory, NULL, &ref405ep_fpga_ops, fpga,
                           "fpga", 0x00000100);
     memory_region_add_subregion(sysmem, base, fpga_memory);
     qemu_register_reset(&ref405ep_fpga_reset, fpga);
@@ -197,11 +197,11 @@ static void ref405ep_init(QEMUMachineInitArgs *args)
     MemoryRegion *sysmem = get_system_memory();
 
     /* XXX: fix this */
-    memory_region_init_ram(&ram_memories[0], "ef405ep.ram", 0x08000000);
+    memory_region_init_ram(&ram_memories[0], NULL, "ef405ep.ram", 0x08000000);
     vmstate_register_ram_global(&ram_memories[0]);
     ram_bases[0] = 0;
     ram_sizes[0] = 0x08000000;
-    memory_region_init(&ram_memories[1], "ef405ep.ram1", 0);
+    memory_region_init(&ram_memories[1], NULL, "ef405ep.ram1", 0);
     ram_bases[1] = 0x00000000;
     ram_sizes[1] = 0x00000000;
     ram_size = 128 * 1024 * 1024;
@@ -212,7 +212,7 @@ static void ref405ep_init(QEMUMachineInitArgs *args)
                         33333333, &pic, kernel_filename == NULL ? 0 : 1);
     /* allocate SRAM */
     sram_size = 512 * 1024;
-    memory_region_init_ram(sram, "ef405ep.sram", sram_size);
+    memory_region_init_ram(sram, NULL, "ef405ep.sram", sram_size);
     vmstate_register_ram_global(sram);
     memory_region_add_subregion(sysmem, 0xFFF00000, sram);
     /* allocate and load BIOS */
@@ -244,7 +244,7 @@ static void ref405ep_init(QEMUMachineInitArgs *args)
         printf("Load BIOS from file\n");
 #endif
         bios = g_new(MemoryRegion, 1);
-        memory_region_init_ram(bios, "ef405ep.bios", BIOS_SIZE);
+        memory_region_init_ram(bios, NULL, "ef405ep.bios", BIOS_SIZE);
         vmstate_register_ram_global(bios);
         if (bios_name == NULL)
             bios_name = BIOS_FILENAME;
@@ -490,7 +490,7 @@ static void taihu_cpld_init(MemoryRegion *sysmem, uint32_t base)
     MemoryRegion *cpld_memory = g_new(MemoryRegion, 1);
 
     cpld = g_malloc0(sizeof(taihu_cpld_t));
-    memory_region_init_io(cpld_memory, &taihu_cpld_ops, cpld, "cpld", 0x100);
+    memory_region_init_io(cpld_memory, NULL, &taihu_cpld_ops, cpld, "cpld", 0x100);
     memory_region_add_subregion(sysmem, base, cpld_memory);
     qemu_register_reset(&taihu_cpld_reset, cpld);
 }
@@ -514,12 +514,12 @@ static void taihu_405ep_init(QEMUMachineInitArgs *args)
     DriveInfo *dinfo;
 
     /* RAM is soldered to the board so the size cannot be changed */
-    memory_region_init_ram(&ram_memories[0],
+    memory_region_init_ram(&ram_memories[0], NULL,
                            "taihu_405ep.ram-0", 0x04000000);
     vmstate_register_ram_global(&ram_memories[0]);
     ram_bases[0] = 0;
     ram_sizes[0] = 0x04000000;
-    memory_region_init_ram(&ram_memories[1],
+    memory_region_init_ram(&ram_memories[1], NULL,
                            "taihu_405ep.ram-1", 0x04000000);
     vmstate_register_ram_global(&ram_memories[1]);
     ram_bases[1] = 0x04000000;
@@ -563,7 +563,7 @@ static void taihu_405ep_init(QEMUMachineInitArgs *args)
         if (bios_name == NULL)
             bios_name = BIOS_FILENAME;
         bios = g_new(MemoryRegion, 1);
-        memory_region_init_ram(bios, "taihu_405ep.bios", BIOS_SIZE);
+        memory_region_init_ram(bios, NULL, "taihu_405ep.bios", BIOS_SIZE);
         vmstate_register_ram_global(bios);
         filename = qemu_find_file(QEMU_FILE_TYPE_BIOS, bios_name);
         if (filename) {
diff --git a/hw/ppc/ppc405_uc.c b/hw/ppc/ppc405_uc.c
index c6c909e..290f71a 100644
--- a/hw/ppc/ppc405_uc.c
+++ b/hw/ppc/ppc405_uc.c
@@ -390,7 +390,7 @@ static void ppc4xx_opba_init(hwaddr base)
 #ifdef DEBUG_OPBA
     printf("%s: offset " TARGET_FMT_plx "\n", __func__, base);
 #endif
-    memory_region_init_io(&opba->io, &opba_ops, opba, "opba", 0x002);
+    memory_region_init_io(&opba->io, NULL, &opba_ops, opba, "opba", 0x002);
     memory_region_add_subregion(get_system_memory(), base, &opba->io);
     qemu_register_reset(ppc4xx_opba_reset, opba);
 }
@@ -812,7 +812,7 @@ static void ppc405_gpio_init(hwaddr base)
 #ifdef DEBUG_GPIO
     printf("%s: offset " TARGET_FMT_plx "\n", __func__, base);
 #endif
-    memory_region_init_io(&gpio->io, &ppc405_gpio_ops, gpio, "pgio", 0x038);
+    memory_region_init_io(&gpio->io, NULL, &ppc405_gpio_ops, gpio, "pgio", 0x038);
     memory_region_add_subregion(get_system_memory(), base, &gpio->io);
     qemu_register_reset(&ppc405_gpio_reset, gpio);
 }
@@ -972,9 +972,9 @@ static void ppc405_ocm_init(CPUPPCState *env)
 
     ocm = g_malloc0(sizeof(ppc405_ocm_t));
     /* XXX: Size is 4096 or 0x04000000 */
-    memory_region_init_ram(&ocm->isarc_ram, "ppc405.ocm", 4096);
+    memory_region_init_ram(&ocm->isarc_ram, NULL, "ppc405.ocm", 4096);
     vmstate_register_ram_global(&ocm->isarc_ram);
-    memory_region_init_alias(&ocm->dsarc_ram, "ppc405.dsarc", &ocm->isarc_ram,
+    memory_region_init_alias(&ocm->dsarc_ram, NULL, "ppc405.dsarc", &ocm->isarc_ram,
                              0, 4096);
     qemu_register_reset(&ocm_reset, ocm);
     ppc_dcr_register(env, OCM0_ISARC,
@@ -1222,7 +1222,7 @@ static void ppc405_i2c_init(hwaddr base, qemu_irq irq)
 #ifdef DEBUG_I2C
     printf("%s: offset " TARGET_FMT_plx "\n", __func__, base);
 #endif
-    memory_region_init_io(&i2c->iomem, &i2c_ops, i2c, "i2c", 0x011);
+    memory_region_init_io(&i2c->iomem, NULL, &i2c_ops, i2c, "i2c", 0x011);
     memory_region_add_subregion(get_system_memory(), base, &i2c->iomem);
     qemu_register_reset(ppc4xx_i2c_reset, i2c);
 }
@@ -1501,7 +1501,7 @@ static void ppc4xx_gpt_init(hwaddr base, qemu_irq irqs[5])
 #ifdef DEBUG_GPT
     printf("%s: offset " TARGET_FMT_plx "\n", __func__, base);
 #endif
-    memory_region_init_io(&gpt->iomem, &gpt_ops, gpt, "gpt", 0x0d4);
+    memory_region_init_io(&gpt->iomem, NULL, &gpt_ops, gpt, "gpt", 0x0d4);
     memory_region_add_subregion(get_system_memory(), base, &gpt->iomem);
     qemu_register_reset(ppc4xx_gpt_reset, gpt);
 }
diff --git a/hw/ppc/ppc4xx_devs.c b/hw/ppc/ppc4xx_devs.c
index d8e3dae..239aada 100644
--- a/hw/ppc/ppc4xx_devs.c
+++ b/hw/ppc/ppc4xx_devs.c
@@ -431,7 +431,7 @@ static void sdram_set_bcr(ppc4xx_sdram_t *sdram,
         printf("%s: Map RAM area " TARGET_FMT_plx " " TARGET_FMT_lx "\n",
                __func__, sdram_base(bcr), sdram_size(bcr));
 #endif
-        memory_region_init(&sdram->containers[n], "sdram-containers",
+        memory_region_init(&sdram->containers[n], NULL, "sdram-containers",
                            sdram_size(bcr));
         memory_region_add_subregion(&sdram->containers[n], 0,
                                     &sdram->ram_memories[n]);
@@ -696,7 +696,7 @@ ram_addr_t ppc4xx_sdram_adjust(ram_addr_t ram_size, int nr_banks,
             if (bank_size <= size_left) {
                 char name[32];
                 snprintf(name, sizeof(name), "ppc4xx.sdram%d", i);
-                memory_region_init_ram(&ram_memories[i], name, bank_size);
+                memory_region_init_ram(&ram_memories[i], NULL, name, bank_size);
                 vmstate_register_ram_global(&ram_memories[i]);
                 ram_bases[i] = base;
                 ram_sizes[i] = bank_size;
diff --git a/hw/ppc/ppc4xx_pci.c b/hw/ppc/ppc4xx_pci.c
index 599539b..f227043 100644
--- a/hw/ppc/ppc4xx_pci.c
+++ b/hw/ppc/ppc4xx_pci.c
@@ -355,12 +355,12 @@ static int ppc4xx_pcihost_initfn(SysBusDevice *dev)
     pci_create_simple(b, 0, "ppc4xx-host-bridge");
 
     /* XXX split into 2 memory regions, one for config space, one for regs */
-    memory_region_init(&s->container, "pci-container", PCI_ALL_SIZE);
-    memory_region_init_io(&h->conf_mem, &pci_host_conf_le_ops, h,
+    memory_region_init(&s->container, NULL, "pci-container", PCI_ALL_SIZE);
+    memory_region_init_io(&h->conf_mem, NULL, &pci_host_conf_le_ops, h,
                           "pci-conf-idx", 4);
-    memory_region_init_io(&h->data_mem, &pci_host_data_le_ops, h,
+    memory_region_init_io(&h->data_mem, NULL, &pci_host_data_le_ops, h,
                           "pci-conf-data", 4);
-    memory_region_init_io(&s->iomem, &pci_reg_ops, s,
+    memory_region_init_io(&s->iomem, NULL, &pci_reg_ops, s,
                           "pci.reg", PCI_REG_SIZE);
     memory_region_add_subregion(&s->container, PCIC0_CFGADDR, &h->conf_mem);
     memory_region_add_subregion(&s->container, PCIC0_CFGDATA, &h->data_mem);
diff --git a/hw/ppc/ppce500_spin.c b/hw/ppc/ppce500_spin.c
index 1290d37..b504d9c 100644
--- a/hw/ppc/ppce500_spin.c
+++ b/hw/ppc/ppce500_spin.c
@@ -191,7 +191,7 @@ static int ppce500_spin_initfn(SysBusDevice *dev)
 
     s = FROM_SYSBUS(SpinState, SYS_BUS_DEVICE(dev));
 
-    memory_region_init_io(&s->iomem, &spin_rw_ops, s, "e500 spin pv device",
+    memory_region_init_io(&s->iomem, NULL, &spin_rw_ops, s, "e500 spin pv device",
                           sizeof(SpinInfo) * MAX_CPUS);
     sysbus_init_mmio(dev, &s->iomem);
 
diff --git a/hw/ppc/prep.c b/hw/ppc/prep.c
index e7689ad..6c81e62 100644
--- a/hw/ppc/prep.c
+++ b/hw/ppc/prep.c
@@ -505,12 +505,12 @@ static void ppc_prep_init(QEMUMachineInitArgs *args)
     }
 
     /* allocate RAM */
-    memory_region_init_ram(ram, "ppc_prep.ram", ram_size);
+    memory_region_init_ram(ram, NULL, "ppc_prep.ram", ram_size);
     vmstate_register_ram_global(ram);
     memory_region_add_subregion(sysmem, 0, ram);
 
     /* allocate and load BIOS */
-    memory_region_init_ram(bios, "ppc_prep.bios", BIOS_SIZE);
+    memory_region_init_ram(bios, NULL, "ppc_prep.bios", BIOS_SIZE);
     memory_region_set_readonly(bios, true);
     memory_region_add_subregion(sysmem, (uint32_t)(-BIOS_SIZE), bios);
     vmstate_register_ram_global(bios);
@@ -621,7 +621,7 @@ static void ppc_prep_init(QEMUMachineInitArgs *args)
     qdev_init_nofail(dev);
 
     /* Register 8 MB of ISA IO space (needed for non-contiguous map) */
-    memory_region_init_io(PPC_io_memory, &PPC_prep_io_ops, sysctrl,
+    memory_region_init_io(PPC_io_memory, NULL, &PPC_prep_io_ops, sysctrl,
                           "ppc-io", 0x00800000);
     memory_region_add_subregion(sysmem, 0x80000000, PPC_io_memory);
 
@@ -658,7 +658,7 @@ static void ppc_prep_init(QEMUMachineInitArgs *args)
 
     /* PowerPC control and status register group */
 #if 0
-    memory_region_init_io(xcsr, &PPC_XCSR_ops, NULL, "ppc-xcsr", 0x1000);
+    memory_region_init_io(xcsr, NULL, &PPC_XCSR_ops, NULL, "ppc-xcsr", 0x1000);
     memory_region_add_subregion(sysmem, 0xFEFF0000, xcsr);
 #endif
 
diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 218ea23..808e130 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -835,7 +835,7 @@ static void ppc_spapr_init(QEMUMachineInitArgs *args)
         ram_addr_t nonrma_base = rma_alloc_size;
         ram_addr_t nonrma_size = spapr->ram_limit - rma_alloc_size;
 
-        memory_region_init_ram(ram, "ppc_spapr.ram", nonrma_size);
+        memory_region_init_ram(ram, NULL, "ppc_spapr.ram", nonrma_size);
         vmstate_register_ram_global(ram);
         memory_region_add_subregion(sysmem, nonrma_base, ram);
     }
diff --git a/hw/ppc/spapr_iommu.c b/hw/ppc/spapr_iommu.c
index 91bc8e4..3976af6 100644
--- a/hw/ppc/spapr_iommu.c
+++ b/hw/ppc/spapr_iommu.c
@@ -151,7 +151,7 @@ sPAPRTCETable *spapr_tce_new_table(uint32_t liobn, size_t window_size)
             "table @ %p, fd=%d\n", tcet, liobn, tcet->table, tcet->fd);
 #endif
 
-    memory_region_init_iommu(&tcet->iommu, &spapr_iommu_ops,
+    memory_region_init_iommu(&tcet->iommu, NULL, &spapr_iommu_ops,
                              "iommu-spapr", UINT64_MAX);
 
     QLIST_INSERT_HEAD(&spapr_tce_tables, tcet, list);
diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c
index 04e8362..04f755f 100644
--- a/hw/ppc/spapr_pci.c
+++ b/hw/ppc/spapr_pci.c
@@ -580,10 +580,10 @@ static int spapr_phb_init(SysBusDevice *s)
 
     /* Initialize memory regions */
     sprintf(namebuf, "%s.mmio", sphb->dtbusname);
-    memory_region_init(&sphb->memspace, namebuf, INT64_MAX);
+    memory_region_init(&sphb->memspace, NULL, namebuf, INT64_MAX);
 
     sprintf(namebuf, "%s.mmio-alias", sphb->dtbusname);
-    memory_region_init_alias(&sphb->memwindow, namebuf, &sphb->memspace,
+    memory_region_init_alias(&sphb->memwindow, NULL, namebuf, &sphb->memspace,
                              SPAPR_PCI_MEM_WIN_BUS_OFFSET, sphb->mem_win_size);
     memory_region_add_subregion(get_system_memory(), sphb->mem_win_addr,
                                 &sphb->memwindow);
@@ -597,12 +597,12 @@ static int spapr_phb_init(SysBusDevice *s)
      * system_io works around the problem until all the users of
      * old_portion are updated */
     sprintf(namebuf, "%s.io", sphb->dtbusname);
-    memory_region_init(&sphb->iospace, namebuf, SPAPR_PCI_IO_WIN_SIZE);
+    memory_region_init(&sphb->iospace, NULL, namebuf, SPAPR_PCI_IO_WIN_SIZE);
     /* FIXME: fix to support multiple PHBs */
     memory_region_add_subregion(get_system_io(), 0, &sphb->iospace);
 
     sprintf(namebuf, "%s.io-alias", sphb->dtbusname);
-    memory_region_init_io(&sphb->iowindow, &spapr_io_ops, sphb,
+    memory_region_init_io(&sphb->iowindow, NULL, &spapr_io_ops, sphb,
                           namebuf, SPAPR_PCI_IO_WIN_SIZE);
     memory_region_add_subregion(get_system_memory(), sphb->io_win_addr,
                                 &sphb->iowindow);
@@ -612,7 +612,7 @@ static int spapr_phb_init(SysBusDevice *s)
      * from msi_notify()/msix_notify() */
     if (msi_supported) {
         sprintf(namebuf, "%s.msi", sphb->dtbusname);
-        memory_region_init_io(&sphb->msiwindow, &spapr_msi_ops, sphb,
+        memory_region_init_io(&sphb->msiwindow, NULL, &spapr_msi_ops, sphb,
                               namebuf, SPAPR_MSIX_MAX_DEVS * 0x10000);
         memory_region_add_subregion(get_system_memory(), sphb->msi_win_addr,
                                     &sphb->msiwindow);
diff --git a/hw/ppc/virtex_ml507.c b/hw/ppc/virtex_ml507.c
index 709a707..08e77fb 100644
--- a/hw/ppc/virtex_ml507.c
+++ b/hw/ppc/virtex_ml507.c
@@ -190,7 +190,7 @@ static void virtex_init(QEMUMachineInitArgs *args)
     env = &cpu->env;
     qemu_register_reset(main_cpu_reset, cpu);
 
-    memory_region_init_ram(phys_ram, "ram", ram_size);
+    memory_region_init_ram(phys_ram, NULL, "ram", ram_size);
     vmstate_register_ram_global(phys_ram);
     memory_region_add_subregion(address_space_mem, ram_base, phys_ram);
 
diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index eb774d9..aebbbf1 100644
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -89,7 +89,7 @@ static void ccw_init(QEMUMachineInitArgs *args)
     virtio_ccw_register_hcalls();
 
     /* allocate RAM */
-    memory_region_init_ram(ram, "s390.ram", my_ram_size);
+    memory_region_init_ram(ram, NULL, "s390.ram", my_ram_size);
     vmstate_register_ram_global(ram);
     memory_region_add_subregion(sysmem, 0, ram);
 
diff --git a/hw/s390x/s390-virtio.c b/hw/s390x/s390-virtio.c
index 30d1118..edbde00 100644
--- a/hw/s390x/s390-virtio.c
+++ b/hw/s390x/s390-virtio.c
@@ -256,7 +256,7 @@ static void s390_init(QEMUMachineInitArgs *args)
     s390_virtio_register_hcalls();
 
     /* allocate RAM */
-    memory_region_init_ram(ram, "s390.ram", my_ram_size);
+    memory_region_init_ram(ram, NULL, "s390.ram", my_ram_size);
     vmstate_register_ram_global(ram);
     memory_region_add_subregion(sysmem, 0, ram);
 
diff --git a/hw/scsi/esp-pci.c b/hw/scsi/esp-pci.c
index 029789a..384224f 100644
--- a/hw/scsi/esp-pci.c
+++ b/hw/scsi/esp-pci.c
@@ -349,7 +349,7 @@ static int esp_pci_scsi_init(PCIDevice *dev)
     s->dma_memory_write = esp_pci_dma_memory_write;
     s->dma_opaque = pci;
     s->chip_id = TCHI_AM53C974;
-    memory_region_init_io(&pci->io, &esp_pci_io_ops, pci, "esp-io", 0x80);
+    memory_region_init_io(&pci->io, NULL, &esp_pci_io_ops, pci, "esp-io", 0x80);
 
     pci_register_bar(&pci->dev, 0, PCI_BASE_ADDRESS_SPACE_IO, &pci->io);
     s->irq = pci->dev.irq[0];
diff --git a/hw/scsi/esp.c b/hw/scsi/esp.c
index 0c81a50..5da5d7a 100644
--- a/hw/scsi/esp.c
+++ b/hw/scsi/esp.c
@@ -675,7 +675,7 @@ static int sysbus_esp_init(SysBusDevice *dev)
     assert(sysbus->it_shift != -1);
 
     s->chip_id = TCHI_FAS100A;
-    memory_region_init_io(&sysbus->iomem, &sysbus_esp_mem_ops, sysbus,
+    memory_region_init_io(&sysbus->iomem, NULL, &sysbus_esp_mem_ops, sysbus,
                           "esp", ESP_REGS << sysbus->it_shift);
     sysbus_init_mmio(dev, &sysbus->iomem);
 
diff --git a/hw/scsi/lsi53c895a.c b/hw/scsi/lsi53c895a.c
index 22b8e98..b31f0b7 100644
--- a/hw/scsi/lsi53c895a.c
+++ b/hw/scsi/lsi53c895a.c
@@ -2090,9 +2090,9 @@ static int lsi_scsi_init(PCIDevice *dev)
     /* Interrupt pin A */
     pci_conf[PCI_INTERRUPT_PIN] = 0x01;
 
-    memory_region_init_io(&s->mmio_io, &lsi_mmio_ops, s, "lsi-mmio", 0x400);
-    memory_region_init_io(&s->ram_io, &lsi_ram_ops, s, "lsi-ram", 0x2000);
-    memory_region_init_io(&s->io_io, &lsi_io_ops, s, "lsi-io", 256);
+    memory_region_init_io(&s->mmio_io, NULL, &lsi_mmio_ops, s, "lsi-mmio", 0x400);
+    memory_region_init_io(&s->ram_io, NULL, &lsi_ram_ops, s, "lsi-ram", 0x2000);
+    memory_region_init_io(&s->io_io, NULL, &lsi_io_ops, s, "lsi-io", 256);
 
     pci_register_bar(&s->dev, 0, PCI_BASE_ADDRESS_SPACE_IO, &s->io_io);
     pci_register_bar(&s->dev, 1, 0, &s->mmio_io);
diff --git a/hw/scsi/megasas.c b/hw/scsi/megasas.c
index 65ccb09..ba74f0b 100644
--- a/hw/scsi/megasas.c
+++ b/hw/scsi/megasas.c
@@ -2098,11 +2098,11 @@ static int megasas_scsi_init(PCIDevice *dev)
     /* Interrupt pin 1 */
     pci_conf[PCI_INTERRUPT_PIN] = 0x01;
 
-    memory_region_init_io(&s->mmio_io, &megasas_mmio_ops, s,
+    memory_region_init_io(&s->mmio_io, NULL, &megasas_mmio_ops, s,
                           "megasas-mmio", 0x4000);
-    memory_region_init_io(&s->port_io, &megasas_port_ops, s,
+    memory_region_init_io(&s->port_io, NULL, &megasas_port_ops, s,
                           "megasas-io", 256);
-    memory_region_init_io(&s->queue_io, &megasas_queue_ops, s,
+    memory_region_init_io(&s->queue_io, NULL, &megasas_queue_ops, s,
                           "megasas-queue", 0x40000);
 
 #ifdef USE_MSIX
diff --git a/hw/scsi/vmw_pvscsi.c b/hw/scsi/vmw_pvscsi.c
index 7cf4044..b7a1275 100644
--- a/hw/scsi/vmw_pvscsi.c
+++ b/hw/scsi/vmw_pvscsi.c
@@ -1075,7 +1075,7 @@ pvscsi_init(PCIDevice *pci_dev)
     /* Interrupt pin A */
     pci_config_set_interrupt_pin(pci_dev->config, 1);
 
-    memory_region_init_io(&s->io_space, &pvscsi_ops, s,
+    memory_region_init_io(&s->io_space, NULL, &pvscsi_ops, s,
                           "pvscsi-io", PVSCSI_MEM_SPACE_SIZE);
     pci_register_bar(pci_dev, 0, PCI_BASE_ADDRESS_SPACE_MEMORY, &s->io_space);
 
diff --git a/hw/sd/milkymist-memcard.c b/hw/sd/milkymist-memcard.c
index 61a8aad..6de050f 100644
--- a/hw/sd/milkymist-memcard.c
+++ b/hw/sd/milkymist-memcard.c
@@ -253,7 +253,7 @@ static int milkymist_memcard_init(SysBusDevice *dev)
     s->card = sd_init(dinfo ? dinfo->bdrv : NULL, false);
     s->enabled = dinfo ? bdrv_is_inserted(dinfo->bdrv) : 0;
 
-    memory_region_init_io(&s->regs_region, &memcard_mmio_ops, s,
+    memory_region_init_io(&s->regs_region, NULL, &memcard_mmio_ops, s,
             "milkymist-memcard", R_MAX * 4);
     sysbus_init_mmio(dev, &s->regs_region);
 
diff --git a/hw/sd/omap_mmc.c b/hw/sd/omap_mmc.c
index ba9f4b3..bf5d1fb 100644
--- a/hw/sd/omap_mmc.c
+++ b/hw/sd/omap_mmc.c
@@ -588,7 +588,7 @@ struct omap_mmc_s *omap_mmc_init(hwaddr base,
 
     omap_mmc_reset(s);
 
-    memory_region_init_io(&s->iomem, &omap_mmc_ops, s, "omap.mmc", 0x800);
+    memory_region_init_io(&s->iomem, NULL, &omap_mmc_ops, s, "omap.mmc", 0x800);
     memory_region_add_subregion(sysmem, base, &s->iomem);
 
     /* Instantiate the storage */
@@ -612,7 +612,7 @@ struct omap_mmc_s *omap2_mmc_init(struct omap_target_agent_s *ta,
 
     omap_mmc_reset(s);
 
-    memory_region_init_io(&s->iomem, &omap_mmc_ops, s, "omap.mmc",
+    memory_region_init_io(&s->iomem, NULL, &omap_mmc_ops, s, "omap.mmc",
                           omap_l4_region_size(ta, 0));
     omap_l4_attach(ta, 0, &s->iomem);
 
diff --git a/hw/sd/pl181.c b/hw/sd/pl181.c
index e08fd04..15f7890 100644
--- a/hw/sd/pl181.c
+++ b/hw/sd/pl181.c
@@ -479,7 +479,7 @@ static int pl181_init(SysBusDevice *dev)
     pl181_state *s = FROM_SYSBUS(pl181_state, dev);
     DriveInfo *dinfo;
 
-    memory_region_init_io(&s->iomem, &pl181_ops, s, "pl181", 0x1000);
+    memory_region_init_io(&s->iomem, NULL, &pl181_ops, s, "pl181", 0x1000);
     sysbus_init_mmio(dev, &s->iomem);
     sysbus_init_irq(dev, &s->irq[0]);
     sysbus_init_irq(dev, &s->irq[1]);
diff --git a/hw/sd/pxa2xx_mmci.c b/hw/sd/pxa2xx_mmci.c
index 0574d6b..90c955f 100644
--- a/hw/sd/pxa2xx_mmci.c
+++ b/hw/sd/pxa2xx_mmci.c
@@ -533,7 +533,7 @@ PXA2xxMMCIState *pxa2xx_mmci_init(MemoryRegion *sysmem,
     s->rx_dma = rx_dma;
     s->tx_dma = tx_dma;
 
-    memory_region_init_io(&s->iomem, &pxa2xx_mmci_ops, s,
+    memory_region_init_io(&s->iomem, NULL, &pxa2xx_mmci_ops, s,
                           "pxa2xx-mmci", 0x00100000);
     memory_region_add_subregion(sysmem, base, &s->iomem);
 
diff --git a/hw/sd/sdhci.c b/hw/sd/sdhci.c
index b9dd4be..ac219c0 100644
--- a/hw/sd/sdhci.c
+++ b/hw/sd/sdhci.c
@@ -1245,7 +1245,7 @@ static void sdhci_realize(DeviceState *dev, Error ** errp)
     s->buf_maxsz = sdhci_get_fifolen(s);
     s->fifo_buffer = g_malloc0(s->buf_maxsz);
     sysbus_init_irq(sbd, &s->irq);
-    memory_region_init_io(&s->iomem, &sdhci_mmio_ops, s, "sdhci",
+    memory_region_init_io(&s->iomem, NULL, &sdhci_mmio_ops, s, "sdhci",
             SDHC_REGISTERS_MAP_SIZE);
     sysbus_init_mmio(sbd, &s->iomem);
 }
diff --git a/hw/sh4/r2d.c b/hw/sh4/r2d.c
index 3e4818e..e779416 100644
--- a/hw/sh4/r2d.c
+++ b/hw/sh4/r2d.c
@@ -186,7 +186,7 @@ static qemu_irq *r2d_fpga_init(MemoryRegion *sysmem,
 
     s->irl = irl;
 
-    memory_region_init_io(&s->iomem, &r2d_fpga_ops, s, "r2d-fpga", 0x40);
+    memory_region_init_io(&s->iomem, NULL, &r2d_fpga_ops, s, "r2d-fpga", 0x40);
     memory_region_add_subregion(sysmem, base, &s->iomem);
     return qemu_allocate_irqs(r2d_fpga_irq_set, s, NR_IRQS);
 }
@@ -254,7 +254,7 @@ static void r2d_init(QEMUMachineInitArgs *args)
     qemu_register_reset(main_cpu_reset, reset_info);
 
     /* Allocate memory space */
-    memory_region_init_ram(sdram, "r2d.sdram", SDRAM_SIZE);
+    memory_region_init_ram(sdram, NULL, "r2d.sdram", SDRAM_SIZE);
     vmstate_register_ram_global(sdram);
     memory_region_add_subregion(address_space_mem, SDRAM_BASE, sdram);
     /* Register peripherals */
diff --git a/hw/sh4/sh7750.c b/hw/sh4/sh7750.c
index 03e8bd1..1439ba4 100644
--- a/hw/sh4/sh7750.c
+++ b/hw/sh4/sh7750.c
@@ -730,34 +730,34 @@ SH7750State *sh7750_init(SuperHCPU *cpu, MemoryRegion *sysmem)
     s = g_malloc0(sizeof(SH7750State));
     s->cpu = cpu;
     s->periph_freq = 60000000;	/* 60MHz */
-    memory_region_init_io(&s->iomem, &sh7750_mem_ops, s,
+    memory_region_init_io(&s->iomem, NULL, &sh7750_mem_ops, s,
                           "memory", 0x1fc01000);
 
-    memory_region_init_alias(&s->iomem_1f0, "memory-1f0",
+    memory_region_init_alias(&s->iomem_1f0, NULL, "memory-1f0",
                              &s->iomem, 0x1f000000, 0x1000);
     memory_region_add_subregion(sysmem, 0x1f000000, &s->iomem_1f0);
 
-    memory_region_init_alias(&s->iomem_ff0, "memory-ff0",
+    memory_region_init_alias(&s->iomem_ff0, NULL, "memory-ff0",
                              &s->iomem, 0x1f000000, 0x1000);
     memory_region_add_subregion(sysmem, 0xff000000, &s->iomem_ff0);
 
-    memory_region_init_alias(&s->iomem_1f8, "memory-1f8",
+    memory_region_init_alias(&s->iomem_1f8, NULL, "memory-1f8",
                              &s->iomem, 0x1f800000, 0x1000);
     memory_region_add_subregion(sysmem, 0x1f800000, &s->iomem_1f8);
 
-    memory_region_init_alias(&s->iomem_ff8, "memory-ff8",
+    memory_region_init_alias(&s->iomem_ff8, NULL, "memory-ff8",
                              &s->iomem, 0x1f800000, 0x1000);
     memory_region_add_subregion(sysmem, 0xff800000, &s->iomem_ff8);
 
-    memory_region_init_alias(&s->iomem_1fc, "memory-1fc",
+    memory_region_init_alias(&s->iomem_1fc, NULL, "memory-1fc",
                              &s->iomem, 0x1fc00000, 0x1000);
     memory_region_add_subregion(sysmem, 0x1fc00000, &s->iomem_1fc);
 
-    memory_region_init_alias(&s->iomem_ffc, "memory-ffc",
+    memory_region_init_alias(&s->iomem_ffc, NULL, "memory-ffc",
                              &s->iomem, 0x1fc00000, 0x1000);
     memory_region_add_subregion(sysmem, 0xffc00000, &s->iomem_ffc);
 
-    memory_region_init_io(&s->mmct_iomem, &sh7750_mmct_ops, s,
+    memory_region_init_io(&s->mmct_iomem, NULL, &sh7750_mmct_ops, s,
                           "cache-and-tlb", 0x08000000);
     memory_region_add_subregion(sysmem, 0xf0000000, &s->mmct_iomem);
 
diff --git a/hw/sh4/sh_pci.c b/hw/sh4/sh_pci.c
index d213a90..8b842bc 100644
--- a/hw/sh4/sh_pci.c
+++ b/hw/sh4/sh_pci.c
@@ -125,9 +125,9 @@ static int sh_pci_device_init(SysBusDevice *dev)
                               get_system_memory(),
                               get_system_io(),
                               PCI_DEVFN(0, 0), 4, TYPE_PCI_BUS);
-    memory_region_init_io(&s->memconfig_p4, &sh_pci_reg_ops, s,
+    memory_region_init_io(&s->memconfig_p4, NULL, &sh_pci_reg_ops, s,
                           "sh_pci", 0x224);
-    memory_region_init_alias(&s->memconfig_a7, "sh_pci.2", &s->memconfig_p4,
+    memory_region_init_alias(&s->memconfig_a7, NULL, "sh_pci.2", &s->memconfig_p4,
                              0, 0x224);
     isa_mmio_setup(&s->isa, 0x40000);
     sysbus_init_mmio(dev, &s->memconfig_p4);
diff --git a/hw/sh4/shix.c b/hw/sh4/shix.c
index ffac621..84dd666 100644
--- a/hw/sh4/shix.c
+++ b/hw/sh4/shix.c
@@ -59,16 +59,16 @@ static void shix_init(QEMUMachineInitArgs *args)
 
     /* Allocate memory space */
     printf("Allocating ROM\n");
-    memory_region_init_ram(rom, "shix.rom", 0x4000);
+    memory_region_init_ram(rom, NULL, "shix.rom", 0x4000);
     vmstate_register_ram_global(rom);
     memory_region_set_readonly(rom, true);
     memory_region_add_subregion(sysmem, 0x00000000, rom);
     printf("Allocating SDRAM 1\n");
-    memory_region_init_ram(&sdram[0], "shix.sdram1", 0x01000000);
+    memory_region_init_ram(&sdram[0], NULL, "shix.sdram1", 0x01000000);
     vmstate_register_ram_global(&sdram[0]);
     memory_region_add_subregion(sysmem, 0x08000000, &sdram[0]);
     printf("Allocating SDRAM 2\n");
-    memory_region_init_ram(&sdram[1], "shix.sdram2", 0x01000000);
+    memory_region_init_ram(&sdram[1], NULL, "shix.sdram2", 0x01000000);
     vmstate_register_ram_global(&sdram[1]);
     memory_region_add_subregion(sysmem, 0x0c000000, &sdram[1]);
 
diff --git a/hw/sparc/leon3.c b/hw/sparc/leon3.c
index 78c77ef..5ef282f 100644
--- a/hw/sparc/leon3.c
+++ b/hw/sparc/leon3.c
@@ -147,13 +147,13 @@ static void leon3_generic_hw_init(QEMUMachineInitArgs *args)
         exit(1);
     }
 
-    memory_region_init_ram(ram, "leon3.ram", ram_size);
+    memory_region_init_ram(ram, NULL, "leon3.ram", ram_size);
     vmstate_register_ram_global(ram);
     memory_region_add_subregion(address_space_mem, 0x40000000, ram);
 
     /* Allocate BIOS */
     prom_size = 8 * 1024 * 1024; /* 8Mb */
-    memory_region_init_ram(prom, "Leon3.bios", prom_size);
+    memory_region_init_ram(prom, NULL, "Leon3.bios", prom_size);
     vmstate_register_ram_global(prom);
     memory_region_set_readonly(prom, true);
     memory_region_add_subregion(address_space_mem, 0x00000000, prom);
diff --git a/hw/sparc/sun4m.c b/hw/sparc/sun4m.c
index 0e86ca7..1a16c82 100644
--- a/hw/sparc/sun4m.c
+++ b/hw/sparc/sun4m.c
@@ -582,7 +582,7 @@ static int idreg_init1(SysBusDevice *dev)
 {
     IDRegState *s = FROM_SYSBUS(IDRegState, dev);
 
-    memory_region_init_ram(&s->mem, "sun4m.idreg", sizeof(idreg_data));
+    memory_region_init_ram(&s->mem, NULL, "sun4m.idreg", sizeof(idreg_data));
     vmstate_register_ram_global(&s->mem);
     memory_region_set_readonly(&s->mem, true);
     sysbus_init_mmio(dev, &s->mem);
@@ -625,7 +625,7 @@ static int afx_init1(SysBusDevice *dev)
 {
     AFXState *s = FROM_SYSBUS(AFXState, dev);
 
-    memory_region_init_ram(&s->mem, "sun4m.afx", 4);
+    memory_region_init_ram(&s->mem, NULL, "sun4m.afx", 4);
     vmstate_register_ram_global(&s->mem);
     sysbus_init_mmio(dev, &s->mem);
     return 0;
@@ -695,7 +695,7 @@ static int prom_init1(SysBusDevice *dev)
 {
     PROMState *s = FROM_SYSBUS(PROMState, dev);
 
-    memory_region_init_ram(&s->prom, "sun4m.prom", PROM_SIZE_MAX);
+    memory_region_init_ram(&s->prom, NULL, "sun4m.prom", PROM_SIZE_MAX);
     vmstate_register_ram_global(&s->prom);
     memory_region_set_readonly(&s->prom, true);
     sysbus_init_mmio(dev, &s->prom);
@@ -734,7 +734,7 @@ static int ram_init1(SysBusDevice *dev)
 {
     RamDevice *d = FROM_SYSBUS(RamDevice, dev);
 
-    memory_region_init_ram(&d->ram, "sun4m.ram", d->size);
+    memory_region_init_ram(&d->ram, NULL, "sun4m.ram", d->size);
     vmstate_register_ram_global(&d->ram);
     sysbus_init_mmio(dev, &d->ram);
     return 0;
diff --git a/hw/sparc64/sun4u.c b/hw/sparc64/sun4u.c
index a6a3b76..4643a83 100644
--- a/hw/sparc64/sun4u.c
+++ b/hw/sparc64/sun4u.c
@@ -680,7 +680,7 @@ static int prom_init1(SysBusDevice *dev)
 {
     PROMState *s = FROM_SYSBUS(PROMState, dev);
 
-    memory_region_init_ram(&s->prom, "sun4u.prom", PROM_SIZE_MAX);
+    memory_region_init_ram(&s->prom, NULL, "sun4u.prom", PROM_SIZE_MAX);
     vmstate_register_ram_global(&s->prom);
     memory_region_set_readonly(&s->prom, true);
     sysbus_init_mmio(dev, &s->prom);
@@ -720,7 +720,7 @@ static int ram_init1(SysBusDevice *dev)
 {
     RamDevice *d = FROM_SYSBUS(RamDevice, dev);
 
-    memory_region_init_ram(&d->ram, "sun4u.ram", d->size);
+    memory_region_init_ram(&d->ram, NULL, "sun4u.ram", d->size);
     vmstate_register_ram_global(&d->ram);
     sysbus_init_mmio(dev, &d->ram);
     return 0;
diff --git a/hw/ssi/omap_spi.c b/hw/ssi/omap_spi.c
index 11403c4..0ed3b11 100644
--- a/hw/ssi/omap_spi.c
+++ b/hw/ssi/omap_spi.c
@@ -354,7 +354,7 @@ struct omap_mcspi_s *omap_mcspi_init(struct omap_target_agent_s *ta, int chnum,
     }
     omap_mcspi_reset(s);
 
-    memory_region_init_io(&s->iomem, &omap_mcspi_ops, s, "omap.mcspi",
+    memory_region_init_io(&s->iomem, NULL, &omap_mcspi_ops, s, "omap.mcspi",
                           omap_l4_region_size(ta, 0));
     omap_l4_attach(ta, 0, &s->iomem);
 
diff --git a/hw/ssi/pl022.c b/hw/ssi/pl022.c
index 536c216..ab569d6 100644
--- a/hw/ssi/pl022.c
+++ b/hw/ssi/pl022.c
@@ -277,7 +277,7 @@ static int pl022_init(SysBusDevice *dev)
 {
     pl022_state *s = FROM_SYSBUS(pl022_state, dev);
 
-    memory_region_init_io(&s->iomem, &pl022_ops, s, "pl022", 0x1000);
+    memory_region_init_io(&s->iomem, NULL, &pl022_ops, s, "pl022", 0x1000);
     sysbus_init_mmio(dev, &s->iomem);
     sysbus_init_irq(dev, &s->irq);
     s->ssi = ssi_create_bus(&dev->qdev, "ssi");
diff --git a/hw/ssi/xilinx_spi.c b/hw/ssi/xilinx_spi.c
index f6bd3ba..7a3c356 100644
--- a/hw/ssi/xilinx_spi.c
+++ b/hw/ssi/xilinx_spi.c
@@ -330,7 +330,7 @@ static int xilinx_spi_init(SysBusDevice *dev)
         sysbus_init_irq(dev, &s->cs_lines[i]);
     }
 
-    memory_region_init_io(&s->mmio, &spi_ops, s, "xilinx-spi", R_MAX * 4);
+    memory_region_init_io(&s->mmio, NULL, &spi_ops, s, "xilinx-spi", R_MAX * 4);
     sysbus_init_mmio(dev, &s->mmio);
 
     s->irqline = -1;
diff --git a/hw/ssi/xilinx_spips.c b/hw/ssi/xilinx_spips.c
index 05a3ada..d7b5074 100644
--- a/hw/ssi/xilinx_spips.c
+++ b/hw/ssi/xilinx_spips.c
@@ -663,7 +663,7 @@ static void xilinx_spips_realize(DeviceState *dev, Error **errp)
         sysbus_init_irq(sbd, &s->cs_lines[i]);
     }
 
-    memory_region_init_io(&s->iomem, xsc->reg_ops, s, "spi", R_MAX*4);
+    memory_region_init_io(&s->iomem, NULL, xsc->reg_ops, s, "spi", R_MAX*4);
     sysbus_init_mmio(sbd, &s->iomem);
 
     s->irqline = -1;
@@ -685,7 +685,7 @@ static void xilinx_qspips_realize(DeviceState *dev, Error **errp)
     s->num_txrx_bytes = 4;
 
     xilinx_spips_realize(dev, errp);
-    memory_region_init_io(&s->mmlqspi, &lqspi_ops, s, "lqspi",
+    memory_region_init_io(&s->mmlqspi, NULL, &lqspi_ops, s, "lqspi",
                           (1 << LQSPI_ADDRESS_BITS) * 2);
     sysbus_init_mmio(sbd, &s->mmlqspi);
 
diff --git a/hw/timer/arm_mptimer.c b/hw/timer/arm_mptimer.c
index 317f5e4..e78f820 100644
--- a/hw/timer/arm_mptimer.c
+++ b/hw/timer/arm_mptimer.c
@@ -236,14 +236,14 @@ static int arm_mptimer_init(SysBusDevice *dev)
      *  * timer for core 1
      * and so on.
      */
-    memory_region_init_io(&s->iomem, &arm_thistimer_ops, s,
+    memory_region_init_io(&s->iomem, NULL, &arm_thistimer_ops, s,
                           "arm_mptimer_timer", 0x20);
     sysbus_init_mmio(dev, &s->iomem);
     for (i = 0; i < s->num_cpu; i++) {
         TimerBlock *tb = &s->timerblock[i];
         tb->timer = qemu_new_timer_ns(vm_clock, timerblock_tick, tb);
         sysbus_init_irq(dev, &tb->irq);
-        memory_region_init_io(&tb->iomem, &timerblock_ops, tb,
+        memory_region_init_io(&tb->iomem, NULL, &timerblock_ops, tb,
                               "arm_mptimer_timerblock", 0x20);
         sysbus_init_mmio(dev, &tb->iomem);
     }
diff --git a/hw/timer/arm_timer.c b/hw/timer/arm_timer.c
index 6449870..f1a501f 100644
--- a/hw/timer/arm_timer.c
+++ b/hw/timer/arm_timer.c
@@ -284,7 +284,7 @@ static int sp804_init(SysBusDevice *dev)
     s->timer[1] = arm_timer_init(s->freq1);
     s->timer[0]->irq = qi[0];
     s->timer[1]->irq = qi[1];
-    memory_region_init_io(&s->iomem, &sp804_ops, s, "sp804", 0x1000);
+    memory_region_init_io(&s->iomem, NULL, &sp804_ops, s, "sp804", 0x1000);
     sysbus_init_mmio(dev, &s->iomem);
     vmstate_register(&dev->qdev, -1, &vmstate_sp804, s);
     return 0;
@@ -347,7 +347,7 @@ static int icp_pit_init(SysBusDevice *dev)
     sysbus_init_irq(dev, &s->timer[1]->irq);
     sysbus_init_irq(dev, &s->timer[2]->irq);
 
-    memory_region_init_io(&s->iomem, &icp_pit_ops, s, "icp_pit", 0x1000);
+    memory_region_init_io(&s->iomem, NULL, &icp_pit_ops, s, "icp_pit", 0x1000);
     sysbus_init_mmio(dev, &s->iomem);
     /* This device has no state to save/restore.  The component timers will
        save themselves.  */
diff --git a/hw/timer/cadence_ttc.c b/hw/timer/cadence_ttc.c
index ba584f4..4879cb0 100644
--- a/hw/timer/cadence_ttc.c
+++ b/hw/timer/cadence_ttc.c
@@ -409,7 +409,7 @@ static int cadence_ttc_init(SysBusDevice *dev)
         sysbus_init_irq(dev, &s->timer[i].irq);
     }
 
-    memory_region_init_io(&s->iomem, &cadence_ttc_ops, s, "timer", 0x1000);
+    memory_region_init_io(&s->iomem, NULL, &cadence_ttc_ops, s, "timer", 0x1000);
     sysbus_init_mmio(dev, &s->iomem);
 
     return 0;
diff --git a/hw/timer/etraxfs_timer.c b/hw/timer/etraxfs_timer.c
index 3cd9476..8a7b177 100644
--- a/hw/timer/etraxfs_timer.c
+++ b/hw/timer/etraxfs_timer.c
@@ -323,7 +323,7 @@ static int etraxfs_timer_init(SysBusDevice *dev)
     sysbus_init_irq(dev, &t->irq);
     sysbus_init_irq(dev, &t->nmi);
 
-    memory_region_init_io(&t->mmio, &timer_ops, t, "etraxfs-timer", 0x5c);
+    memory_region_init_io(&t->mmio, NULL, &timer_ops, t, "etraxfs-timer", 0x5c);
     sysbus_init_mmio(dev, &t->mmio);
     qemu_register_reset(etraxfs_timer_reset, t);
     return 0;
diff --git a/hw/timer/exynos4210_mct.c b/hw/timer/exynos4210_mct.c
index 38dcc1a..ba74d2b 100644
--- a/hw/timer/exynos4210_mct.c
+++ b/hw/timer/exynos4210_mct.c
@@ -1449,7 +1449,7 @@ static int exynos4210_mct_init(SysBusDevice *dev)
         sysbus_init_irq(dev, &s->l_timer[i].irq);
     }
 
-    memory_region_init_io(&s->iomem, &exynos4210_mct_ops, s, "exynos4210-mct",
+    memory_region_init_io(&s->iomem, NULL, &exynos4210_mct_ops, s, "exynos4210-mct",
             MCT_SFR_SIZE);
     sysbus_init_mmio(dev, &s->iomem);
 
diff --git a/hw/timer/exynos4210_pwm.c b/hw/timer/exynos4210_pwm.c
index 185ccb9..62c42b4 100644
--- a/hw/timer/exynos4210_pwm.c
+++ b/hw/timer/exynos4210_pwm.c
@@ -390,7 +390,7 @@ static int exynos4210_pwm_init(SysBusDevice *dev)
         s->timer[i].parent = s;
     }
 
-    memory_region_init_io(&s->iomem, &exynos4210_pwm_ops, s, "exynos4210-pwm",
+    memory_region_init_io(&s->iomem, NULL, &exynos4210_pwm_ops, s, "exynos4210-pwm",
             EXYNOS4210_PWM_REG_MEM_SIZE);
     sysbus_init_mmio(dev, &s->iomem);
 
diff --git a/hw/timer/exynos4210_rtc.c b/hw/timer/exynos4210_rtc.c
index 3ac77f9..779dc77 100644
--- a/hw/timer/exynos4210_rtc.c
+++ b/hw/timer/exynos4210_rtc.c
@@ -559,7 +559,7 @@ static int exynos4210_rtc_init(SysBusDevice *dev)
     sysbus_init_irq(dev, &s->alm_irq);
     sysbus_init_irq(dev, &s->tick_irq);
 
-    memory_region_init_io(&s->iomem, &exynos4210_rtc_ops, s, "exynos4210-rtc",
+    memory_region_init_io(&s->iomem, NULL, &exynos4210_rtc_ops, s, "exynos4210-rtc",
             EXYNOS4210_RTC_REG_MEM_SIZE);
     sysbus_init_mmio(dev, &s->iomem);
 
diff --git a/hw/timer/grlib_gptimer.c b/hw/timer/grlib_gptimer.c
index 7043a34..749ed31 100644
--- a/hw/timer/grlib_gptimer.c
+++ b/hw/timer/grlib_gptimer.c
@@ -365,7 +365,7 @@ static int grlib_gptimer_init(SysBusDevice *dev)
         ptimer_set_freq(timer->ptimer, unit->freq_hz);
     }
 
-    memory_region_init_io(&unit->iomem, &grlib_gptimer_ops, unit, "gptimer",
+    memory_region_init_io(&unit->iomem, NULL, &grlib_gptimer_ops, unit, "gptimer",
                           UNIT_REG_SIZE + GPTIMER_REG_SIZE * unit->nr_timers);
 
     sysbus_init_mmio(dev, &unit->iomem);
diff --git a/hw/timer/hpet.c b/hw/timer/hpet.c
index 95dd01d..2e7fdb5 100644
--- a/hw/timer/hpet.c
+++ b/hw/timer/hpet.c
@@ -722,7 +722,7 @@ static int hpet_init(SysBusDevice *dev)
     qdev_init_gpio_out(&dev->qdev, &s->pit_enabled, 1);
 
     /* HPET Area */
-    memory_region_init_io(&s->iomem, &hpet_ram_ops, s, "hpet", 0x400);
+    memory_region_init_io(&s->iomem, NULL, &hpet_ram_ops, s, "hpet", 0x400);
     sysbus_init_mmio(dev, &s->iomem);
     return 0;
 }
diff --git a/hw/timer/i8254.c b/hw/timer/i8254.c
index 16c8dd6..fdb23da 100644
--- a/hw/timer/i8254.c
+++ b/hw/timer/i8254.c
@@ -333,7 +333,7 @@ static void pit_realizefn(DeviceState *dev, Error **err)
     s->irq_timer = qemu_new_timer_ns(vm_clock, pit_irq_timer, s);
     qdev_init_gpio_out(dev, &s->irq, 1);
 
-    memory_region_init_io(&pit->ioports, &pit_ioport_ops, pit, "pit", 4);
+    memory_region_init_io(&pit->ioports, NULL, &pit_ioport_ops, pit, "pit", 4);
 
     qdev_init_gpio_in(dev, pit_irq_control, 1);
 
diff --git a/hw/timer/imx_epit.c b/hw/timer/imx_epit.c
index 7cdb006..d2e0895 100644
--- a/hw/timer/imx_epit.c
+++ b/hw/timer/imx_epit.c
@@ -396,7 +396,7 @@ static void imx_epit_realize(DeviceState *dev, Error **errp)
     DPRINTF("\n");
 
     sysbus_init_irq(sbd, &s->irq);
-    memory_region_init_io(&s->iomem, &imx_epit_ops, s, TYPE_IMX_EPIT,
+    memory_region_init_io(&s->iomem, NULL, &imx_epit_ops, s, TYPE_IMX_EPIT,
                           0x00001000);
     sysbus_init_mmio(sbd, &s->iomem);
 
diff --git a/hw/timer/imx_gpt.c b/hw/timer/imx_gpt.c
index de53b13..6e6442d 100644
--- a/hw/timer/imx_gpt.c
+++ b/hw/timer/imx_gpt.c
@@ -514,7 +514,7 @@ static void imx_gpt_realize(DeviceState *dev, Error **errp)
     QEMUBH *bh;
 
     sysbus_init_irq(sbd, &s->irq);
-    memory_region_init_io(&s->iomem, &imx_gpt_ops, s, TYPE_IMX_GPT,
+    memory_region_init_io(&s->iomem, NULL, &imx_gpt_ops, s, TYPE_IMX_GPT,
                           0x00001000);
     sysbus_init_mmio(sbd, &s->iomem);
 
diff --git a/hw/timer/lm32_timer.c b/hw/timer/lm32_timer.c
index e06fac7..2ab8588 100644
--- a/hw/timer/lm32_timer.c
+++ b/hw/timer/lm32_timer.c
@@ -180,7 +180,7 @@ static int lm32_timer_init(SysBusDevice *dev)
     s->ptimer = ptimer_init(s->bh);
     ptimer_set_freq(s->ptimer, s->freq_hz);
 
-    memory_region_init_io(&s->iomem, &timer_ops, s, "timer", R_MAX * 4);
+    memory_region_init_io(&s->iomem, NULL, &timer_ops, s, "timer", R_MAX * 4);
     sysbus_init_mmio(dev, &s->iomem);
 
     return 0;
diff --git a/hw/timer/m48t59.c b/hw/timer/m48t59.c
index bf6c4c8..fdda6d6 100644
--- a/hw/timer/m48t59.c
+++ b/hw/timer/m48t59.c
@@ -655,7 +655,7 @@ M48t59State *m48t59_init(qemu_irq IRQ, hwaddr mem_base,
     d = FROM_SYSBUS(M48t59SysBusState, s);
     state = &d->state;
     sysbus_connect_irq(s, 0, IRQ);
-    memory_region_init_io(&d->io, &m48t59_io_ops, state, "m48t59", 4);
+    memory_region_init_io(&d->io, NULL, &m48t59_io_ops, state, "m48t59", 4);
     if (io_base != 0) {
         memory_region_add_subregion(get_system_io(), io_base, &d->io);
     }
@@ -683,7 +683,7 @@ M48t59State *m48t59_init_isa(ISABus *bus, uint32_t io_base, uint16_t size,
     d = ISA_M48T59(isadev);
     s = &d->state;
 
-    memory_region_init_io(&d->io, &m48t59_io_ops, s, "m48t59", 4);
+    memory_region_init_io(&d->io, NULL, &m48t59_io_ops, s, "m48t59", 4);
     if (io_base != 0) {
         isa_register_ioport(isadev, &d->io, io_base);
     }
@@ -721,7 +721,7 @@ static int m48t59_init1(SysBusDevice *dev)
 
     sysbus_init_irq(dev, &s->IRQ);
 
-    memory_region_init_io(&s->iomem, &nvram_ops, s, "m48t59.nvram", s->size);
+    memory_region_init_io(&s->iomem, NULL, &nvram_ops, s, "m48t59.nvram", s->size);
     sysbus_init_mmio(dev, &s->iomem);
     m48t59_realize_common(s, &err);
     if (err != NULL) {
diff --git a/hw/timer/mc146818rtc.c b/hw/timer/mc146818rtc.c
index 9c4a7bd..4110a37 100644
--- a/hw/timer/mc146818rtc.c
+++ b/hw/timer/mc146818rtc.c
@@ -863,7 +863,7 @@ static void rtc_realizefn(DeviceState *dev, Error **errp)
     s->suspend_notifier.notify = rtc_notify_suspend;
     qemu_register_suspend_notifier(&s->suspend_notifier);
 
-    memory_region_init_io(&s->io, &cmos_ops, s, "rtc", 2);
+    memory_region_init_io(&s->io, NULL, &cmos_ops, s, "rtc", 2);
     isa_register_ioport(isadev, &s->io, base);
 
     qdev_set_legacy_instance_id(dev, base, 3);
diff --git a/hw/timer/milkymist-sysctl.c b/hw/timer/milkymist-sysctl.c
index e083a28..f253f21 100644
--- a/hw/timer/milkymist-sysctl.c
+++ b/hw/timer/milkymist-sysctl.c
@@ -280,7 +280,7 @@ static int milkymist_sysctl_init(SysBusDevice *dev)
     ptimer_set_freq(s->ptimer0, s->freq_hz);
     ptimer_set_freq(s->ptimer1, s->freq_hz);
 
-    memory_region_init_io(&s->regs_region, &sysctl_mmio_ops, s,
+    memory_region_init_io(&s->regs_region, NULL, &sysctl_mmio_ops, s,
             "milkymist-sysctl", R_MAX * 4);
     sysbus_init_mmio(dev, &s->regs_region);
 
diff --git a/hw/timer/omap_gptimer.c b/hw/timer/omap_gptimer.c
index 9b0e9dd..ac389d8 100644
--- a/hw/timer/omap_gptimer.c
+++ b/hw/timer/omap_gptimer.c
@@ -480,7 +480,7 @@ struct omap_gp_timer_s *omap_gp_timer_init(struct omap_target_agent_s *ta,
     omap_gp_timer_reset(s);
     omap_gp_timer_clk_setup(s);
 
-    memory_region_init_io(&s->iomem, &omap_gp_timer_ops, s, "omap.gptimer",
+    memory_region_init_io(&s->iomem, NULL, &omap_gp_timer_ops, s, "omap.gptimer",
                           omap_l4_region_size(ta, 0));
     omap_l4_attach(ta, 0, &s->iomem);
 
diff --git a/hw/timer/omap_synctimer.c b/hw/timer/omap_synctimer.c
index a24f35c..a12aca2 100644
--- a/hw/timer/omap_synctimer.c
+++ b/hw/timer/omap_synctimer.c
@@ -94,7 +94,7 @@ struct omap_synctimer_s *omap_synctimer_init(struct omap_target_agent_s *ta,
     struct omap_synctimer_s *s = g_malloc0(sizeof(*s));
 
     omap_synctimer_reset(s);
-    memory_region_init_io(&s->iomem, &omap_synctimer_ops, s, "omap.synctimer",
+    memory_region_init_io(&s->iomem, NULL, &omap_synctimer_ops, s, "omap.synctimer",
                           omap_l4_region_size(ta, 0));
     omap_l4_attach(ta, 0, &s->iomem);
 
diff --git a/hw/timer/pl031.c b/hw/timer/pl031.c
index 764940b..cba4e87 100644
--- a/hw/timer/pl031.c
+++ b/hw/timer/pl031.c
@@ -192,7 +192,7 @@ static int pl031_init(SysBusDevice *dev)
     pl031_state *s = FROM_SYSBUS(pl031_state, dev);
     struct tm tm;
 
-    memory_region_init_io(&s->iomem, &pl031_ops, s, "pl031", 0x1000);
+    memory_region_init_io(&s->iomem, NULL, &pl031_ops, s, "pl031", 0x1000);
     sysbus_init_mmio(dev, &s->iomem);
 
     sysbus_init_irq(dev, &s->irq);
diff --git a/hw/timer/puv3_ost.c b/hw/timer/puv3_ost.c
index 0c3d827..375d368 100644
--- a/hw/timer/puv3_ost.c
+++ b/hw/timer/puv3_ost.c
@@ -122,7 +122,7 @@ static int puv3_ost_init(SysBusDevice *dev)
     s->ptimer = ptimer_init(s->bh);
     ptimer_set_freq(s->ptimer, 50 * 1000 * 1000);
 
-    memory_region_init_io(&s->iomem, &puv3_ost_ops, s, "puv3_ost",
+    memory_region_init_io(&s->iomem, NULL, &puv3_ost_ops, s, "puv3_ost",
             PUV3_REGS_OFFSET);
     sysbus_init_mmio(dev, &s->iomem);
 
diff --git a/hw/timer/pxa2xx_timer.c b/hw/timer/pxa2xx_timer.c
index 8ea2416..dd41a10 100644
--- a/hw/timer/pxa2xx_timer.c
+++ b/hw/timer/pxa2xx_timer.c
@@ -461,7 +461,7 @@ static int pxa2xx_timer_init(SysBusDevice *dev)
         }
     }
 
-    memory_region_init_io(&s->iomem, &pxa2xx_timer_ops, s,
+    memory_region_init_io(&s->iomem, NULL, &pxa2xx_timer_ops, s,
                           "pxa2xx-timer", 0x00001000);
     sysbus_init_mmio(dev, &s->iomem);
 
diff --git a/hw/timer/sh_timer.c b/hw/timer/sh_timer.c
index f92ff4f..251a10d 100644
--- a/hw/timer/sh_timer.c
+++ b/hw/timer/sh_timer.c
@@ -319,14 +319,14 @@ void tmu012_init(MemoryRegion *sysmem, hwaddr base,
         s->timer[2] = sh_timer_init(freq, timer_feat | TIMER_FEAT_CAPT,
 				    ch2_irq0); /* ch2_irq1 not supported */
 
-    memory_region_init_io(&s->iomem, &tmu012_ops, s,
+    memory_region_init_io(&s->iomem, NULL, &tmu012_ops, s,
                           "timer", 0x100000000ULL);
 
-    memory_region_init_alias(&s->iomem_p4, "timer-p4",
+    memory_region_init_alias(&s->iomem_p4, NULL, "timer-p4",
                              &s->iomem, 0, 0x1000);
     memory_region_add_subregion(sysmem, P4ADDR(base), &s->iomem_p4);
 
-    memory_region_init_alias(&s->iomem_a7, "timer-a7",
+    memory_region_init_alias(&s->iomem_a7, NULL, "timer-a7",
                              &s->iomem, 0, 0x1000);
     memory_region_add_subregion(sysmem, A7ADDR(base), &s->iomem_a7);
     /* ??? Save/restore.  */
diff --git a/hw/timer/slavio_timer.c b/hw/timer/slavio_timer.c
index 1145a87..cad81a3 100644
--- a/hw/timer/slavio_timer.c
+++ b/hw/timer/slavio_timer.c
@@ -394,7 +394,7 @@ static int slavio_timer_init1(SysBusDevice *dev)
 
         size = i == 0 ? SYS_TIMER_SIZE : CPU_TIMER_SIZE;
         snprintf(timer_name, sizeof(timer_name), "timer-%i", i);
-        memory_region_init_io(&tc->iomem, &slavio_timer_mem_ops, tc,
+        memory_region_init_io(&tc->iomem, NULL, &slavio_timer_mem_ops, tc,
                               timer_name, size);
         sysbus_init_mmio(dev, &tc->iomem);
 
diff --git a/hw/timer/tusb6010.c b/hw/timer/tusb6010.c
index 50edc06..fcce4ac 100644
--- a/hw/timer/tusb6010.c
+++ b/hw/timer/tusb6010.c
@@ -779,7 +779,7 @@ static int tusb6010_init(SysBusDevice *dev)
     TUSBState *s = FROM_SYSBUS(TUSBState, dev);
     s->otg_timer = qemu_new_timer_ns(vm_clock, tusb_otg_tick, s);
     s->pwr_timer = qemu_new_timer_ns(vm_clock, tusb_power_tick, s);
-    memory_region_init_io(&s->iomem[1], &tusb_async_ops, s, "tusb-async",
+    memory_region_init_io(&s->iomem[1], NULL, &tusb_async_ops, s, "tusb-async",
                           UINT32_MAX);
     sysbus_init_mmio(dev, &s->iomem[0]);
     sysbus_init_mmio(dev, &s->iomem[1]);
diff --git a/hw/timer/xilinx_timer.c b/hw/timer/xilinx_timer.c
index 0c39cff..f4b4fb5 100644
--- a/hw/timer/xilinx_timer.c
+++ b/hw/timer/xilinx_timer.c
@@ -218,7 +218,7 @@ static int xilinx_timer_init(SysBusDevice *dev)
         ptimer_set_freq(xt->ptimer, t->freq_hz);
     }
 
-    memory_region_init_io(&t->mmio, &timer_ops, t, "xlnx.xps-timer",
+    memory_region_init_io(&t->mmio, NULL, &timer_ops, t, "xlnx.xps-timer",
                           R_MAX * 4 * num_timers(t));
     sysbus_init_mmio(dev, &t->mmio);
     return 0;
diff --git a/hw/tpm/tpm_tis.c b/hw/tpm/tpm_tis.c
index d4d8152..5504fb4 100644
--- a/hw/tpm/tpm_tis.c
+++ b/hw/tpm/tpm_tis.c
@@ -888,7 +888,7 @@ static void tpm_tis_initfn(Object *obj)
     ISADevice *dev = ISA_DEVICE(obj);
     TPMState *s = TPM(obj);
 
-    memory_region_init_io(&s->mmio, &tpm_tis_memory_ops, s, "tpm-tis-mmio",
+    memory_region_init_io(&s->mmio, NULL, &tpm_tis_memory_ops, s, "tpm-tis-mmio",
                           TPM_TIS_NUM_LOCALITIES << TPM_TIS_LOCALITY_SHIFT);
     memory_region_add_subregion(isa_address_space(dev), TPM_TIS_ADDR_BASE,
                                 &s->mmio);
diff --git a/hw/unicore32/puv3.c b/hw/unicore32/puv3.c
index 56d1afa..5ff0dc9 100644
--- a/hw/unicore32/puv3.c
+++ b/hw/unicore32/puv3.c
@@ -73,7 +73,7 @@ static void puv3_board_init(CPUUniCore32State *env, ram_addr_t ram_size)
     MemoryRegion *ram_memory = g_new(MemoryRegion, 1);
 
     /* SDRAM at address zero.  */
-    memory_region_init_ram(ram_memory, "puv3.ram", ram_size);
+    memory_region_init_ram(ram_memory, NULL, "puv3.ram", ram_size);
     vmstate_register_ram_global(ram_memory);
     memory_region_add_subregion(get_system_memory(), 0, ram_memory);
 }
diff --git a/hw/usb/hcd-ehci-sysbus.c b/hw/usb/hcd-ehci-sysbus.c
index e7d4f74..76b4c05 100644
--- a/hw/usb/hcd-ehci-sysbus.c
+++ b/hw/usb/hcd-ehci-sysbus.c
@@ -173,7 +173,7 @@ static void fusbh200_ehci_init(Object *obj)
     FUSBH200EHCIState *f = FUSBH200_EHCI(obj);
     EHCIState *s = &i->ehci;
 
-    memory_region_init_io(&f->mem_vendor, &fusbh200_ehci_mmio_ops, s,
+    memory_region_init_io(&f->mem_vendor, NULL, &fusbh200_ehci_mmio_ops, s,
                           "fusbh200", 0x4c);
     memory_region_add_subregion(&s->mem,
                                 s->opregbase + s->portscbase + 4 * s->portnr,
diff --git a/hw/usb/hcd-ehci.c b/hw/usb/hcd-ehci.c
index 65e6680..07d72e6 100644
--- a/hw/usb/hcd-ehci.c
+++ b/hw/usb/hcd-ehci.c
@@ -2551,12 +2551,12 @@ void usb_ehci_init(EHCIState *s, DeviceState *dev)
     QTAILQ_INIT(&s->pqueues);
     usb_packet_init(&s->ipacket);
 
-    memory_region_init(&s->mem, "ehci", MMIO_SIZE);
-    memory_region_init_io(&s->mem_caps, &ehci_mmio_caps_ops, s,
+    memory_region_init(&s->mem, NULL, "ehci", MMIO_SIZE);
+    memory_region_init_io(&s->mem_caps, NULL, &ehci_mmio_caps_ops, s,
                           "capabilities", CAPA_SIZE);
-    memory_region_init_io(&s->mem_opreg, &ehci_mmio_opreg_ops, s,
+    memory_region_init_io(&s->mem_opreg, NULL, &ehci_mmio_opreg_ops, s,
                           "operational", s->portscbase);
-    memory_region_init_io(&s->mem_ports, &ehci_mmio_port_ops, s,
+    memory_region_init_io(&s->mem_ports, NULL, &ehci_mmio_port_ops, s,
                           "ports", 4 * s->portnr);
 
     memory_region_add_subregion(&s->mem, s->capsbase, &s->mem_caps);
diff --git a/hw/usb/hcd-ohci.c b/hw/usb/hcd-ohci.c
index 5513924..aa51042 100644
--- a/hw/usb/hcd-ohci.c
+++ b/hw/usb/hcd-ohci.c
@@ -1830,7 +1830,7 @@ static int usb_ohci_init(OHCIState *ohci, DeviceState *dev,
         }
     }
 
-    memory_region_init_io(&ohci->mem, &ohci_mem_ops, ohci, "ohci", 256);
+    memory_region_init_io(&ohci->mem, NULL, &ohci_mem_ops, ohci, "ohci", 256);
     ohci->localmem_base = localmem_base;
 
     ohci->name = object_get_typename(OBJECT(dev));
diff --git a/hw/usb/hcd-uhci.c b/hw/usb/hcd-uhci.c
index c85b203..502228b 100644
--- a/hw/usb/hcd-uhci.c
+++ b/hw/usb/hcd-uhci.c
@@ -1259,7 +1259,7 @@ static int usb_uhci_common_initfn(PCIDevice *dev)
 
     qemu_register_reset(uhci_reset, s);
 
-    memory_region_init_io(&s->io_bar, &uhci_ioport_ops, s, "uhci", 0x20);
+    memory_region_init_io(&s->io_bar, NULL, &uhci_ioport_ops, s, "uhci", 0x20);
     /* Use region 4 for consistency with real hardware.  BSD guests seem
        to rely on this.  */
     pci_register_bar(&s->dev, 4, PCI_BASE_ADDRESS_SPACE_IO, &s->io_bar);
diff --git a/hw/usb/hcd-xhci.c b/hw/usb/hcd-xhci.c
index 91633ed..493d759 100644
--- a/hw/usb/hcd-xhci.c
+++ b/hw/usb/hcd-xhci.c
@@ -3342,14 +3342,14 @@ static int usb_xhci_initfn(struct PCIDevice *dev)
 
     xhci->irq = xhci->pci_dev.irq[0];
 
-    memory_region_init(&xhci->mem, "xhci", LEN_REGS);
-    memory_region_init_io(&xhci->mem_cap, &xhci_cap_ops, xhci,
+    memory_region_init(&xhci->mem, NULL, "xhci", LEN_REGS);
+    memory_region_init_io(&xhci->mem_cap, NULL, &xhci_cap_ops, xhci,
                           "capabilities", LEN_CAP);
-    memory_region_init_io(&xhci->mem_oper, &xhci_oper_ops, xhci,
+    memory_region_init_io(&xhci->mem_oper, NULL, &xhci_oper_ops, xhci,
                           "operational", 0x400);
-    memory_region_init_io(&xhci->mem_runtime, &xhci_runtime_ops, xhci,
+    memory_region_init_io(&xhci->mem_runtime, NULL, &xhci_runtime_ops, xhci,
                           "runtime", LEN_RUNTIME);
-    memory_region_init_io(&xhci->mem_doorbell, &xhci_doorbell_ops, xhci,
+    memory_region_init_io(&xhci->mem_doorbell, NULL, &xhci_doorbell_ops, xhci,
                           "doorbell", LEN_DOORBELL);
 
     memory_region_add_subregion(&xhci->mem, 0,            &xhci->mem_cap);
@@ -3361,7 +3361,7 @@ static int usb_xhci_initfn(struct PCIDevice *dev)
         XHCIPort *port = &xhci->ports[i];
         uint32_t offset = OFF_OPER + 0x400 + 0x10 * i;
         port->xhci = xhci;
-        memory_region_init_io(&port->mem, &xhci_port_ops, port,
+        memory_region_init_io(&port->mem, NULL, &xhci_port_ops, port,
                               port->name, 0x10);
         memory_region_add_subregion(&xhci->mem, offset, &port->mem);
     }
diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index b070b64..c8ecc8e 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -966,7 +966,7 @@ static void virtio_pci_device_plugged(DeviceState *d)
         size = 1 << qemu_fls(size);
     }
 
-    memory_region_init_io(&proxy->bar, &virtio_pci_config_ops, proxy,
+    memory_region_init_io(&proxy->bar, NULL, &virtio_pci_config_ops, proxy,
                           "virtio-pci", size);
     pci_register_bar(&proxy->pci_dev, 0, PCI_BASE_ADDRESS_SPACE_IO,
                      &proxy->bar);
diff --git a/hw/watchdog/wdt_i6300esb.c b/hw/watchdog/wdt_i6300esb.c
index 05af0b1..2c75014 100644
--- a/hw/watchdog/wdt_i6300esb.c
+++ b/hw/watchdog/wdt_i6300esb.c
@@ -417,7 +417,7 @@ static int i6300esb_init(PCIDevice *dev)
     d->timer = qemu_new_timer_ns(vm_clock, i6300esb_timer_expired, d);
     d->previous_reboot_flag = 0;
 
-    memory_region_init_io(&d->io_mem, &i6300esb_ops, d, "i6300esb", 0x10);
+    memory_region_init_io(&d->io_mem, NULL, &i6300esb_ops, d, "i6300esb", 0x10);
     pci_register_bar(&d->dev, 0, 0, &d->io_mem);
     /* qemu_register_coalesced_mmio (addr, 0x10); ? */
 
diff --git a/hw/xen/xen_apic.c b/hw/xen/xen_apic.c
index a958782..3526ffe 100644
--- a/hw/xen/xen_apic.c
+++ b/hw/xen/xen_apic.c
@@ -38,7 +38,7 @@ static const MemoryRegionOps xen_apic_io_ops = {
 
 static void xen_apic_init(APICCommonState *s)
 {
-    memory_region_init_io(&s->io_memory, &xen_apic_io_ops, s, "xen-apic-msi",
+    memory_region_init_io(&s->io_memory, NULL, &xen_apic_io_ops, s, "xen-apic-msi",
                           APIC_SPACE_SIZE);
 
 #if defined(CONFIG_XEN_CTRL_INTERFACE_VERSION) \
diff --git a/hw/xen/xen_platform.c b/hw/xen/xen_platform.c
index f8f5dd5..8855309 100644
--- a/hw/xen/xen_platform.c
+++ b/hw/xen/xen_platform.c
@@ -275,7 +275,7 @@ static const MemoryRegionOps platform_fixed_io_ops = {
 
 static void platform_fixed_ioport_init(PCIXenPlatformState* s)
 {
-    memory_region_init_io(&s->fixed_io, &platform_fixed_io_ops, s,
+    memory_region_init_io(&s->fixed_io, NULL, &platform_fixed_io_ops, s,
                           "xen-fixed", 16);
     memory_region_add_subregion(get_system_io(), XEN_PLATFORM_IOPORT,
                                 &s->fixed_io);
@@ -319,7 +319,7 @@ static const MemoryRegionOps xen_pci_io_ops = {
 
 static void platform_ioport_bar_setup(PCIXenPlatformState *d)
 {
-    memory_region_init_io(&d->bar, &xen_pci_io_ops, d, "xen-pci", 0x100);
+    memory_region_init_io(&d->bar, NULL, &xen_pci_io_ops, d, "xen-pci", 0x100);
 }
 
 static uint64_t platform_mmio_read(void *opaque, hwaddr addr,
@@ -347,7 +347,7 @@ static const MemoryRegionOps platform_mmio_handler = {
 
 static void platform_mmio_setup(PCIXenPlatformState *d)
 {
-    memory_region_init_io(&d->mmio_bar, &platform_mmio_handler, d,
+    memory_region_init_io(&d->mmio_bar, NULL, &platform_mmio_handler, d,
                           "xen-mmio", 0x1000000);
 }
 
diff --git a/hw/xen/xen_pt.c b/hw/xen/xen_pt.c
index c31a28a..15b4896 100644
--- a/hw/xen/xen_pt.c
+++ b/hw/xen/xen_pt.c
@@ -416,7 +416,7 @@ static int xen_pt_register_regions(XenPCIPassthroughState *s)
             }
         }
 
-        memory_region_init_io(&s->bar[i], &ops, &s->dev,
+        memory_region_init_io(&s->bar[i], NULL, &ops, &s->dev,
                               "xen-pci-pt-bar", r->size);
         pci_register_bar(&s->dev, i, type, &s->bar[i]);
 
@@ -440,7 +440,7 @@ static int xen_pt_register_regions(XenPCIPassthroughState *s)
 
         s->bases[PCI_ROM_SLOT].access.maddr = d->rom.base_addr;
 
-        memory_region_init_rom_device(&s->rom, NULL, NULL,
+        memory_region_init_rom_device(&s->rom, NULL, NULL, NULL,
                                       "xen-pci-pt-rom", d->rom.size);
         pci_register_bar(&s->dev, PCI_ROM_SLOT, PCI_BASE_ADDRESS_MEM_PREFETCH,
                          &s->rom);
diff --git a/hw/xen/xen_pt_msi.c b/hw/xen/xen_pt_msi.c
index db2c842..9c7d43b 100644
--- a/hw/xen/xen_pt_msi.c
+++ b/hw/xen/xen_pt_msi.c
@@ -544,7 +544,7 @@ int xen_pt_msix_init(XenPCIPassthroughState *s, uint32_t base)
         msix->msix_entry[i].pirq = XEN_PT_UNASSIGNED_PIRQ;
     }
 
-    memory_region_init_io(&msix->mmio, &pci_msix_ops, s, "xen-pci-pt-msix",
+    memory_region_init_io(&msix->mmio, NULL, &pci_msix_ops, s, "xen-pci-pt-msix",
                           (total_entries * PCI_MSIX_ENTRY_SIZE
                            + XC_PAGE_SIZE - 1)
                           & XC_PAGE_MASK);
diff --git a/hw/xtensa/xtensa_lx60.c b/hw/xtensa/xtensa_lx60.c
index 650dd31..11c30c2 100644
--- a/hw/xtensa/xtensa_lx60.c
+++ b/hw/xtensa/xtensa_lx60.c
@@ -109,7 +109,7 @@ static Lx60FpgaState *lx60_fpga_init(MemoryRegion *address_space,
 {
     Lx60FpgaState *s = g_malloc(sizeof(Lx60FpgaState));
 
-    memory_region_init_io(&s->iomem, &lx60_fpga_ops, s,
+    memory_region_init_io(&s->iomem, NULL, &lx60_fpga_ops, s,
             "lx60.fpga", 0x10000);
     memory_region_add_subregion(address_space, base, &s->iomem);
     lx60_fpga_reset(s);
@@ -139,7 +139,7 @@ static void lx60_net_init(MemoryRegion *address_space,
             sysbus_mmio_get_region(s, 1));
 
     ram = g_malloc(sizeof(*ram));
-    memory_region_init_ram(ram, "open_eth.ram", 16384);
+    memory_region_init_ram(ram, NULL, "open_eth.ram", 16384);
     vmstate_register_ram_global(ram);
     memory_region_add_subregion(address_space, buffers, ram);
 }
@@ -195,12 +195,12 @@ static void lx_init(const LxBoardDesc *board, QEMUMachineInitArgs *args)
     }
 
     ram = g_malloc(sizeof(*ram));
-    memory_region_init_ram(ram, "lx60.dram", args->ram_size);
+    memory_region_init_ram(ram, NULL, "lx60.dram", args->ram_size);
     vmstate_register_ram_global(ram);
     memory_region_add_subregion(system_memory, 0, ram);
 
     system_io = g_malloc(sizeof(*system_io));
-    memory_region_init(system_io, "lx60.io", 224 * 1024 * 1024);
+    memory_region_init(system_io, NULL, "lx60.io", 224 * 1024 * 1024);
     memory_region_add_subregion(system_memory, 0xf0000000, system_io);
     lx60_fpga_init(system_io, 0x0d020000);
     if (nd_table[0].used) {
@@ -231,7 +231,7 @@ static void lx_init(const LxBoardDesc *board, QEMUMachineInitArgs *args)
     /* Use presence of kernel file name as 'boot from SRAM' switch. */
     if (kernel_filename) {
         rom = g_malloc(sizeof(*rom));
-        memory_region_init_ram(rom, "lx60.sram", board->sram_size);
+        memory_region_init_ram(rom, NULL, "lx60.sram", board->sram_size);
         vmstate_register_ram_global(rom);
         memory_region_add_subregion(system_memory, 0xfe000000, rom);
 
@@ -262,7 +262,7 @@ static void lx_init(const LxBoardDesc *board, QEMUMachineInitArgs *args)
             MemoryRegion *flash_mr = pflash_cfi01_get_memory(flash);
             MemoryRegion *flash_io = g_malloc(sizeof(*flash_io));
 
-            memory_region_init_alias(flash_io, "lx60.flash",
+            memory_region_init_alias(flash_io, NULL, "lx60.flash",
                     flash_mr, 0, board->flash_size);
             memory_region_add_subregion(system_memory, 0xfe000000,
                     flash_io);
diff --git a/hw/xtensa/xtensa_sim.c b/hw/xtensa/xtensa_sim.c
index 5241f8d..a88707e 100644
--- a/hw/xtensa/xtensa_sim.c
+++ b/hw/xtensa/xtensa_sim.c
@@ -75,12 +75,12 @@ static void xtensa_sim_init(QEMUMachineInitArgs *args)
     }
 
     ram = g_malloc(sizeof(*ram));
-    memory_region_init_ram(ram, "xtensa.sram", ram_size);
+    memory_region_init_ram(ram, NULL, "xtensa.sram", ram_size);
     vmstate_register_ram_global(ram);
     memory_region_add_subregion(get_system_memory(), 0, ram);
 
     rom = g_malloc(sizeof(*rom));
-    memory_region_init_ram(rom, "xtensa.rom", 0x1000);
+    memory_region_init_ram(rom, NULL, "xtensa.rom", 0x1000);
     vmstate_register_ram_global(rom);
     memory_region_add_subregion(get_system_memory(), 0xfe000000, rom);
 
diff --git a/include/exec/memory.h b/include/exec/memory.h
index 84b3eef..be3d39f 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -134,6 +134,7 @@ struct MemoryRegion {
     const MemoryRegionOps *ops;
     const MemoryRegionIOMMUOps *iommu_ops;
     void *opaque;
+    struct Object *owner;
     MemoryRegion *parent;
     Int128 size;
     hwaddr addr;
@@ -236,10 +237,12 @@ struct MemoryListener {
  * memory_region_add_subregion() to add subregions.
  *
  * @mr: the #MemoryRegion to be initialized
+ * @owner: the object that tracks the region's reference count
  * @name: used for debugging; not visible to the user or ABI
  * @size: size of the region; any subregions beyond this size will be clipped
  */
 void memory_region_init(MemoryRegion *mr,
+                        struct Object *owner,
                         const char *name,
                         uint64_t size);
 /**
@@ -249,6 +252,7 @@ void memory_region_init(MemoryRegion *mr,
  * if @size is nonzero, subregions will be clipped to @size.
  *
  * @mr: the #MemoryRegion to be initialized.
+ * @owner: the object that tracks the region's reference count
  * @ops: a structure containing read and write callbacks to be used when
  *       I/O is performed on the region.
  * @opaque: passed to to the read and write callbacks of the @ops structure.
@@ -256,6 +260,7 @@ void memory_region_init(MemoryRegion *mr,
  * @size: size of the region.
  */
 void memory_region_init_io(MemoryRegion *mr,
+                           struct Object *owner,
                            const MemoryRegionOps *ops,
                            void *opaque,
                            const char *name,
@@ -266,10 +271,12 @@ void memory_region_init_io(MemoryRegion *mr,
  *                          region will modify memory directly.
  *
  * @mr: the #MemoryRegion to be initialized.
+ * @owner: the object that tracks the region's reference count
  * @name: the name of the region.
  * @size: size of the region.
  */
 void memory_region_init_ram(MemoryRegion *mr,
+                            struct Object *owner,
                             const char *name,
                             uint64_t size);
 
@@ -279,11 +286,13 @@ void memory_region_init_ram(MemoryRegion *mr,
  *                              region will modify memory directly.
  *
  * @mr: the #MemoryRegion to be initialized.
+ * @owner: the object that tracks the region's reference count
  * @name: the name of the region.
  * @size: size of the region.
  * @ptr: memory to be mapped; must contain at least @size bytes.
  */
 void memory_region_init_ram_ptr(MemoryRegion *mr,
+                                struct Object *owner,
                                 const char *name,
                                 uint64_t size,
                                 void *ptr);
@@ -293,6 +302,7 @@ void memory_region_init_ram_ptr(MemoryRegion *mr,
  *                           part of another memory region.
  *
  * @mr: the #MemoryRegion to be initialized.
+ * @owner: the object that tracks the region's reference count
  * @name: used for debugging; not visible to the user or ABI
  * @orig: the region to be referenced; @mr will be equivalent to
  *        @orig between @offset and @offset + @size - 1.
@@ -300,6 +310,7 @@ void memory_region_init_ram_ptr(MemoryRegion *mr,
  * @size: size of the region.
  */
 void memory_region_init_alias(MemoryRegion *mr,
+                              struct Object *owner,
                               const char *name,
                               MemoryRegion *orig,
                               hwaddr offset,
@@ -310,11 +321,13 @@ void memory_region_init_alias(MemoryRegion *mr,
  *                                 handled via callbacks.
  *
  * @mr: the #MemoryRegion to be initialized.
+ * @owner: the object that tracks the region's reference count
  * @ops: callbacks for write access handling.
  * @name: the name of the region.
  * @size: size of the region.
  */
 void memory_region_init_rom_device(MemoryRegion *mr,
+                                   struct Object *owner,
                                    const MemoryRegionOps *ops,
                                    void *opaque,
                                    const char *name,
@@ -329,10 +342,12 @@ void memory_region_init_rom_device(MemoryRegion *mr,
  * the memory API will cause an abort().
  *
  * @mr: the #MemoryRegion to be initialized
+ * @owner: the object that tracks the region's reference count
  * @name: used for debugging; not visible to the user or ABI
  * @size: size of the region.
  */
 void memory_region_init_reservation(MemoryRegion *mr,
+                                    struct Object *owner,
                                     const char *name,
                                     uint64_t size);
 
@@ -344,11 +359,13 @@ void memory_region_init_reservation(MemoryRegion *mr,
  * memory region.
  *
  * @mr: the #MemoryRegion to be initialized
+ * @owner: the object that tracks the region's reference count
  * @ops: a function that translates addresses into the @target region
  * @name: used for debugging; not visible to the user or ABI
  * @size: size of the region.
  */
 void memory_region_init_iommu(MemoryRegion *mr,
+                              struct Object *owner,
                               const MemoryRegionIOMMUOps *ops,
                               const char *name,
                               uint64_t size);
diff --git a/ioport.c b/ioport.c
index ef6fb96..3a6a73d 100644
--- a/ioport.c
+++ b/ioport.c
@@ -211,7 +211,7 @@ static void portio_list_add_1(PortioList *piolist,
      * Use an alias so that the callback is called with an absolute address,
      * rather than an offset relative to to start + off_low.
      */
-    memory_region_init_io(&mrpio->mr, &portio_ops, mrpio, piolist->name,
+    memory_region_init_io(&mrpio->mr, NULL, &portio_ops, mrpio, piolist->name,
                           off_high - off_low);
     memory_region_add_subregion(piolist->address_space,
                                 start + off_low, &mrpio->mr);
diff --git a/memory.c b/memory.c
index df07b24..6250bec1 100644
--- a/memory.c
+++ b/memory.c
@@ -17,6 +17,7 @@
 #include "exec/address-spaces.h"
 #include "exec/ioport.h"
 #include "qemu/bitops.h"
+#include "qom/object.h"
 #include "sysemu/kvm.h"
 #include <assert.h>
 
@@ -728,11 +729,13 @@ static bool memory_region_wrong_endianness(MemoryRegion *mr)
 }
 
 void memory_region_init(MemoryRegion *mr,
+                        Object *owner,
                         const char *name,
                         uint64_t size)
 {
     mr->ops = &unassigned_mem_ops;
     mr->opaque = NULL;
+    mr->owner = owner;
     mr->iommu_ops = NULL;
     mr->parent = NULL;
     mr->size = int128_make64(size);
@@ -912,12 +915,13 @@ static bool memory_region_dispatch_write(MemoryRegion *mr,
 }
 
 void memory_region_init_io(MemoryRegion *mr,
+                           Object *owner,
                            const MemoryRegionOps *ops,
                            void *opaque,
                            const char *name,
                            uint64_t size)
 {
-    memory_region_init(mr, name, size);
+    memory_region_init(mr, owner, name, size);
     mr->ops = ops;
     mr->opaque = opaque;
     mr->terminates = true;
@@ -925,10 +929,11 @@ void memory_region_init_io(MemoryRegion *mr,
 }
 
 void memory_region_init_ram(MemoryRegion *mr,
+                            Object *owner,
                             const char *name,
                             uint64_t size)
 {
-    memory_region_init(mr, name, size);
+    memory_region_init(mr, owner, name, size);
     mr->ram = true;
     mr->terminates = true;
     mr->destructor = memory_region_destructor_ram;
@@ -936,11 +941,12 @@ void memory_region_init_ram(MemoryRegion *mr,
 }
 
 void memory_region_init_ram_ptr(MemoryRegion *mr,
+                                Object *owner,
                                 const char *name,
                                 uint64_t size,
                                 void *ptr)
 {
-    memory_region_init(mr, name, size);
+    memory_region_init(mr, owner, name, size);
     mr->ram = true;
     mr->terminates = true;
     mr->destructor = memory_region_destructor_ram_from_ptr;
@@ -948,23 +954,25 @@ void memory_region_init_ram_ptr(MemoryRegion *mr,
 }
 
 void memory_region_init_alias(MemoryRegion *mr,
+                              Object *owner,
                               const char *name,
                               MemoryRegion *orig,
                               hwaddr offset,
                               uint64_t size)
 {
-    memory_region_init(mr, name, size);
+    memory_region_init(mr, owner, name, size);
     mr->alias = orig;
     mr->alias_offset = offset;
 }
 
 void memory_region_init_rom_device(MemoryRegion *mr,
+                                   Object *owner,
                                    const MemoryRegionOps *ops,
                                    void *opaque,
                                    const char *name,
                                    uint64_t size)
 {
-    memory_region_init(mr, name, size);
+    memory_region_init(mr, owner, name, size);
     mr->ops = ops;
     mr->opaque = opaque;
     mr->terminates = true;
@@ -974,21 +982,23 @@ void memory_region_init_rom_device(MemoryRegion *mr,
 }
 
 void memory_region_init_iommu(MemoryRegion *mr,
+                              Object *owner,
                               const MemoryRegionIOMMUOps *ops,
                               const char *name,
                               uint64_t size)
 {
-    memory_region_init(mr, name, size);
+    memory_region_init(mr, owner, name, size);
     mr->iommu_ops = ops,
     mr->terminates = true;  /* then re-forwards */
     notifier_list_init(&mr->iommu_notify);
 }
 
 void memory_region_init_reservation(MemoryRegion *mr,
+                                    Object *owner,
                                     const char *name,
                                     uint64_t size)
 {
-    memory_region_init_io(mr, &unassigned_mem_ops, mr, name, size);
+    memory_region_init_io(mr, owner, &unassigned_mem_ops, mr, name, size);
 }
 
 void memory_region_destroy(MemoryRegion *mr)
diff --git a/target-ppc/kvm.c b/target-ppc/kvm.c
index 2bbc3b8..757290b 100644
--- a/target-ppc/kvm.c
+++ b/target-ppc/kvm.c
@@ -1555,7 +1555,7 @@ off_t kvmppc_alloc_rma(const char *name, MemoryRegion *sysmem)
     };
 
     rma_region = g_new(MemoryRegion, 1);
-    memory_region_init_ram_ptr(rma_region, name, size, rma);
+    memory_region_init_ram_ptr(rma_region, NULL, name, size, rma);
     vmstate_register_ram_global(rma_region);
     memory_region_add_subregion(sysmem, 0, rma_region);
 
diff --git a/xen-all.c b/xen-all.c
index dcb57a0..1f040c0 100644
--- a/xen-all.c
+++ b/xen-all.c
@@ -167,7 +167,7 @@ static void xen_ram_init(ram_addr_t ram_size)
          */
         block_len += HVM_BELOW_4G_MMIO_LENGTH;
     }
-    memory_region_init_ram(&ram_memory, "xen.ram", block_len);
+    memory_region_init_ram(&ram_memory, NULL, "xen.ram", block_len);
     vmstate_register_ram_global(&ram_memory);
 
     if (ram_size >= HVM_BELOW_4G_RAM_END) {
@@ -177,7 +177,7 @@ static void xen_ram_init(ram_addr_t ram_size)
         below_4g_mem_size = ram_size;
     }
 
-    memory_region_init_alias(&ram_640k, "xen.ram.640k",
+    memory_region_init_alias(&ram_640k, NULL, "xen.ram.640k",
                              &ram_memory, 0, 0xa0000);
     memory_region_add_subregion(sysmem, 0, &ram_640k);
     /* Skip of the VGA IO memory space, it will be registered later by the VGA
@@ -186,11 +186,11 @@ static void xen_ram_init(ram_addr_t ram_size)
      * The area between 0xc0000 and 0x100000 will be used by SeaBIOS to load
      * the Options ROM, so it is registered here as RAM.
      */
-    memory_region_init_alias(&ram_lo, "xen.ram.lo",
+    memory_region_init_alias(&ram_lo, NULL, "xen.ram.lo",
                              &ram_memory, 0xc0000, below_4g_mem_size - 0xc0000);
     memory_region_add_subregion(sysmem, 0xc0000, &ram_lo);
     if (above_4g_mem_size > 0) {
-        memory_region_init_alias(&ram_hi, "xen.ram.hi",
+        memory_region_init_alias(&ram_hi, NULL, "xen.ram.hi",
                                  &ram_memory, 0x100000000ULL,
                                  above_4g_mem_size);
         memory_region_add_subregion(sysmem, 0x100000000ULL, &ram_hi);
