diff --git a/hw/apb_pci.c b/hw/apb_pci.c
index 8b9939c..1638226 100644
--- a/hw/apb_pci.c
+++ b/hw/apb_pci.c
@@ -348,6 +348,7 @@ PCIBus *pci_apb_init(target_phys_addr_t special_base,
     d->bus = pci_register_bus(&d->busdev.qdev, "pci",
                                          pci_apb_set_irq, pci_pbm_map_irq, d,
                                          get_system_memory(),
+                                         get_system_io(),
                                          0, 32);
     pci_bus_set_mem_base(d->bus, mem_base);
 
diff --git a/hw/bonito.c b/hw/bonito.c
index 5f62dda..8708e95 100644
--- a/hw/bonito.c
+++ b/hw/bonito.c
@@ -775,6 +775,7 @@ PCIBus *bonito_init(qemu_irq *pic)
     pcihost = FROM_SYSBUS(BonitoState, sysbus_from_qdev(dev));
     b = pci_register_bus(&pcihost->busdev.qdev, "pci", pci_bonito_set_irq,
                          pci_bonito_map_irq, pic, get_system_memory(),
+                         get_system_io(),
                          0x28, 32);
     pcihost->bus = b;
     qdev_init_nofail(dev);
diff --git a/hw/grackle_pci.c b/hw/grackle_pci.c
index da67cf9..9a823e1 100644
--- a/hw/grackle_pci.c
+++ b/hw/grackle_pci.c
@@ -62,7 +62,8 @@ static void pci_grackle_reset(void *opaque)
 }
 
 PCIBus *pci_grackle_init(uint32_t base, qemu_irq *pic,
-                         MemoryRegion *address_space)
+                         MemoryRegion *address_space_mem,
+                         MemoryRegion *address_space_io)
 {
     DeviceState *dev;
     SysBusDevice *s;
@@ -75,7 +76,10 @@ PCIBus *pci_grackle_init(uint32_t base, qemu_irq *pic,
     d->host_state.bus = pci_register_bus(&d->busdev.qdev, "pci",
                                          pci_grackle_set_irq,
                                          pci_grackle_map_irq,
-                                         pic, address_space, 0, 4);
+                                         pic,
+                                         address_space_mem,
+                                         address_space_io,
+                                         0, 4);
 
     pci_create_simple(d->host_state.bus, 0, "grackle");
 
diff --git a/hw/gt64xxx.c b/hw/gt64xxx.c
index 65e63dd..d541558 100644
--- a/hw/gt64xxx.c
+++ b/hw/gt64xxx.c
@@ -1093,7 +1093,9 @@ PCIBus *gt64120_register(qemu_irq *pic)
     d = FROM_SYSBUS(GT64120State, s);
     d->pci.bus = pci_register_bus(&d->busdev.qdev, "pci",
                                   gt64120_pci_set_irq, gt64120_pci_map_irq,
-                                  pic, get_system_memory(),
+                                  pic,
+                                  get_system_memory(),
+                                  get_system_io(),
                                   PCI_DEVFN(18, 0), 4);
     d->ISD_handle = cpu_register_io_memory(gt64120_read, gt64120_write, d,
                                            DEVICE_NATIVE_ENDIAN);
diff --git a/hw/pc.h b/hw/pc.h
index a2de0fe..ec34db7 100644
--- a/hw/pc.h
+++ b/hw/pc.h
@@ -179,7 +179,9 @@ struct PCII440FXState;
 typedef struct PCII440FXState PCII440FXState;
 
 PCIBus *i440fx_init(PCII440FXState **pi440fx_state, int *piix_devfn,
-                    qemu_irq *pic, MemoryRegion *address_space,
+                    qemu_irq *pic,
+                    MemoryRegion *address_space_mem,
+                    MemoryRegion *address_space_io,
                     ram_addr_t ram_size);
 void i440fx_init_memory_mappings(PCII440FXState *d);
 
diff --git a/hw/pc_piix.c b/hw/pc_piix.c
index 2b9c2b1..fb92035 100644
--- a/hw/pc_piix.c
+++ b/hw/pc_piix.c
@@ -69,6 +69,7 @@ static void ioapic_init(IsaIrqState *isa_irq_state)
 
 /* PC hardware initialisation */
 static void pc_init1(MemoryRegion *system_memory,
+                     MemoryRegion *system_io,
                      ram_addr_t ram_size,
                      const char *boot_device,
                      const char *kernel_filename,
@@ -129,7 +130,7 @@ static void pc_init1(MemoryRegion *system_memory,
 
     if (pci_enabled) {
         pci_bus = i440fx_init(&i440fx_state, &piix3_devfn, isa_irq,
-                              system_memory, ram_size);
+                              system_memory, system_io, ram_size);
     } else {
         pci_bus = NULL;
         i440fx_state = NULL;
@@ -214,6 +215,7 @@ static void pc_init_pci(ram_addr_t ram_size,
                         const char *cpu_model)
 {
     pc_init1(get_system_memory(),
+             get_system_io(),
              ram_size, boot_device,
              kernel_filename, kernel_cmdline,
              initrd_filename, cpu_model, 1, 1);
@@ -227,6 +229,7 @@ static void pc_init_pci_no_kvmclock(ram_addr_t ram_size,
                                     const char *cpu_model)
 {
     pc_init1(get_system_memory(),
+             get_system_io(),
              ram_size, boot_device,
              kernel_filename, kernel_cmdline,
              initrd_filename, cpu_model, 1, 0);
@@ -242,6 +245,7 @@ static void pc_init_isa(ram_addr_t ram_size,
     if (cpu_model == NULL)
         cpu_model = "486";
     pc_init1(get_system_memory(),
+             get_system_io(),
              ram_size, boot_device,
              kernel_filename, kernel_cmdline,
              initrd_filename, cpu_model, 0, 1);
diff --git a/hw/pci.c b/hw/pci.c
index 912f849..2659d96 100644
--- a/hw/pci.c
+++ b/hw/pci.c
@@ -264,13 +264,14 @@ int pci_find_domain(const PCIBus *bus)
 
 void pci_bus_new_inplace(PCIBus *bus, DeviceState *parent,
                          const char *name,
-                         MemoryRegion *address_space,
+                         MemoryRegion *address_space_mem,
+                         MemoryRegion *address_space_io,
                          uint8_t devfn_min)
 {
     qbus_create_inplace(&bus->qbus, &pci_bus_info, parent, name);
     assert(PCI_FUNC(devfn_min) == 0);
     bus->devfn_min = devfn_min;
-    bus->address_space = address_space;
+    bus->address_space = address_space_mem;
 
     /* host bridge */
     QLIST_INIT(&bus->child);
@@ -280,13 +281,16 @@ void pci_bus_new_inplace(PCIBus *bus, DeviceState *parent,
 }
 
 PCIBus *pci_bus_new(DeviceState *parent, const char *name,
-                    MemoryRegion *address_space, uint8_t devfn_min)
+                    MemoryRegion *address_space_mem,
+                    MemoryRegion *address_space_io,
+                    uint8_t devfn_min)
 {
     PCIBus *bus;
 
     bus = qemu_mallocz(sizeof(*bus));
     bus->qbus.qdev_allocated = 1;
-    pci_bus_new_inplace(bus, parent, name, address_space, devfn_min);
+    pci_bus_new_inplace(bus, parent, name, address_space_mem,
+                        address_space_io, devfn_min);
     return bus;
 }
 
@@ -315,12 +319,14 @@ void pci_bus_set_mem_base(PCIBus *bus, target_phys_addr_t base)
 PCIBus *pci_register_bus(DeviceState *parent, const char *name,
                          pci_set_irq_fn set_irq, pci_map_irq_fn map_irq,
                          void *irq_opaque,
-                         MemoryRegion *address_space,
+                         MemoryRegion *address_space_mem,
+                         MemoryRegion *address_space_io,
                          uint8_t devfn_min, int nirq)
 {
     PCIBus *bus;
 
-    bus = pci_bus_new(parent, name, address_space, devfn_min);
+    bus = pci_bus_new(parent, name, address_space_mem,
+                      address_space_io, devfn_min);
     pci_bus_irqs(bus, set_irq, map_irq, irq_opaque, nirq);
     return bus;
 }
diff --git a/hw/pci.h b/hw/pci.h
index 64282ad..45b30fa 100644
--- a/hw/pci.h
+++ b/hw/pci.h
@@ -239,10 +239,13 @@ typedef int (*pci_hotplug_fn)(DeviceState *qdev, PCIDevice *pci_dev,
                               PCIHotplugState state);
 void pci_bus_new_inplace(PCIBus *bus, DeviceState *parent,
                          const char *name,
-                         MemoryRegion *address_space,
+                         MemoryRegion *address_space_mem,
+                         MemoryRegion *address_space_io,
                          uint8_t devfn_min);
 PCIBus *pci_bus_new(DeviceState *parent, const char *name,
-                    MemoryRegion *address_space, uint8_t devfn_min);
+                    MemoryRegion *address_space_mem,
+                    MemoryRegion *address_space_io,
+                    uint8_t devfn_min);
 void pci_bus_irqs(PCIBus *bus, pci_set_irq_fn set_irq, pci_map_irq_fn map_irq,
                   void *irq_opaque, int nirq);
 int pci_bus_get_irq_level(PCIBus *bus, int irq_num);
@@ -250,7 +253,8 @@ void pci_bus_hotplug(PCIBus *bus, pci_hotplug_fn hotplug, DeviceState *dev);
 PCIBus *pci_register_bus(DeviceState *parent, const char *name,
                          pci_set_irq_fn set_irq, pci_map_irq_fn map_irq,
                          void *irq_opaque,
-                         MemoryRegion *address_space,
+                         MemoryRegion *address_space_mem,
+                         MemoryRegion *address_space_io,
                          uint8_t devfn_min, int nirq);
 void pci_device_reset(PCIDevice *dev);
 void pci_bus_reset(PCIBus *bus);
diff --git a/hw/piix_pci.c b/hw/piix_pci.c
index 445c6cb..2c106a4 100644
--- a/hw/piix_pci.c
+++ b/hw/piix_pci.c
@@ -242,7 +242,8 @@ static PCIBus *i440fx_common_init(const char *device_name,
                                   PCII440FXState **pi440fx_state,
                                   int *piix3_devfn,
                                   qemu_irq *pic,
-                                  MemoryRegion *address_space,
+                                  MemoryRegion *address_space_mem,
+                                  MemoryRegion *address_space_io,
                                   ram_addr_t ram_size)
 {
     DeviceState *dev;
@@ -253,8 +254,9 @@ static PCIBus *i440fx_common_init(const char *device_name,
 
     dev = qdev_create(NULL, "i440FX-pcihost");
     s = FROM_SYSBUS(I440FXState, sysbus_from_qdev(dev));
-    s->address_space = address_space;
-    b = pci_bus_new(&s->busdev.qdev, NULL, s->address_space, 0);
+    s->address_space = address_space_mem;
+    b = pci_bus_new(&s->busdev.qdev, NULL, s->address_space,
+                    address_space_io, 0);
     s->bus = b;
     qdev_init_nofail(dev);
 
@@ -291,13 +293,15 @@ static PCIBus *i440fx_common_init(const char *device_name,
 }
 
 PCIBus *i440fx_init(PCII440FXState **pi440fx_state, int *piix3_devfn,
-                    qemu_irq *pic, MemoryRegion *address_space,
+                    qemu_irq *pic,
+                    MemoryRegion *address_space_mem,
+                    MemoryRegion *address_space_io,
                     ram_addr_t ram_size)
 {
     PCIBus *b;
 
     b = i440fx_common_init("i440FX", pi440fx_state, piix3_devfn, pic,
-                           address_space, ram_size);
+                           address_space_mem, address_space_io, ram_size);
     return b;
 }
 
diff --git a/hw/ppc4xx_pci.c b/hw/ppc4xx_pci.c
index 15c24f6..c7696b0 100644
--- a/hw/ppc4xx_pci.c
+++ b/hw/ppc4xx_pci.c
@@ -348,6 +348,7 @@ PCIBus *ppc4xx_pci_init(CPUState *env, qemu_irq pci_irqs[4],
                                                  ppc4xx_pci_map_irq,
                                                  pci_irqs,
                                                  get_system_memory(),
+                                                 get_system_io(),
                                                  0, 4);
 
     controller->pci_dev = pci_register_device(controller->pci_state.bus,
diff --git a/hw/ppc_mac.h b/hw/ppc_mac.h
index 6fad20a..25a2274 100644
--- a/hw/ppc_mac.h
+++ b/hw/ppc_mac.h
@@ -55,11 +55,16 @@ qemu_irq *heathrow_pic_init(int *pmem_index,
 
 /* Grackle PCI */
 PCIBus *pci_grackle_init(uint32_t base, qemu_irq *pic,
-                         MemoryRegion *address_space);
+                         MemoryRegion *address_space_mem,
+                         MemoryRegion *address_space_io);
 
 /* UniNorth PCI */
-PCIBus *pci_pmac_init(qemu_irq *pic, MemoryRegion *address_space);
-PCIBus *pci_pmac_u3_init(qemu_irq *pic, MemoryRegion *address_space);
+PCIBus *pci_pmac_init(qemu_irq *pic,
+                      MemoryRegion *address_space_mem,
+                      MemoryRegion *address_space_io);
+PCIBus *pci_pmac_u3_init(qemu_irq *pic,
+                         MemoryRegion *address_space_mem,
+                         MemoryRegion *address_space_io);
 
 /* Mac NVRAM */
 typedef struct MacIONVRAMState MacIONVRAMState;
diff --git a/hw/ppc_newworld.c b/hw/ppc_newworld.c
index 2c0fae8..94a21f9 100644
--- a/hw/ppc_newworld.c
+++ b/hw/ppc_newworld.c
@@ -318,10 +318,10 @@ static void ppc_core99_init (ram_addr_t ram_size,
     pic = openpic_init(NULL, &pic_mem_index, smp_cpus, openpic_irqs, NULL);
     if (PPC_INPUT(env) == PPC_FLAGS_INPUT_970) {
         /* 970 gets a U3 bus */
-        pci_bus = pci_pmac_u3_init(pic, get_system_memory());
+        pci_bus = pci_pmac_u3_init(pic, get_system_memory(), get_system_io());
         machine_arch = ARCH_MAC99_U3;
     } else {
-        pci_bus = pci_pmac_init(pic, get_system_memory());
+        pci_bus = pci_pmac_init(pic, get_system_memory(), get_system_io());
         machine_arch = ARCH_MAC99;
     }
     /* init basic PC hardware */
diff --git a/hw/ppc_oldworld.c b/hw/ppc_oldworld.c
index 585afd6..0f99eef 100644
--- a/hw/ppc_oldworld.c
+++ b/hw/ppc_oldworld.c
@@ -234,7 +234,9 @@ static void ppc_heathrow_init (ram_addr_t ram_size,
         hw_error("Only 6xx bus is supported on heathrow machine\n");
     }
     pic = heathrow_pic_init(&pic_mem_index, 1, heathrow_irqs);
-    pci_bus = pci_grackle_init(0xfec00000, pic, get_system_memory());
+    pci_bus = pci_grackle_init(0xfec00000, pic,
+                               get_system_memory(),
+                               get_system_io());
     pci_vga_init(pci_bus);
 
     escc_mem_index = escc_init(0x80013000, pic[0x0f], pic[0x10], serial_hds[0],
diff --git a/hw/ppc_prep.c b/hw/ppc_prep.c
index 91ebe07..38d8573 100644
--- a/hw/ppc_prep.c
+++ b/hw/ppc_prep.c
@@ -649,7 +649,7 @@ static void ppc_prep_init (ram_addr_t ram_size,
         hw_error("Only 6xx bus is supported on PREP machine\n");
     }
     i8259 = i8259_init(first_cpu->irq_inputs[PPC6xx_INPUT_INT]);
-    pci_bus = pci_prep_init(i8259, get_system_memory());
+    pci_bus = pci_prep_init(i8259, get_system_memory(), get_system_io());
     /* Hmm, prep has no pci-isa bridge ??? */
     isa_bus_new(NULL);
     isa_bus_irqs(i8259);
diff --git a/hw/ppce500_pci.c b/hw/ppce500_pci.c
index 1344539..6a9f979 100644
--- a/hw/ppce500_pci.c
+++ b/hw/ppce500_pci.c
@@ -282,7 +282,8 @@ static int e500_pcihost_initfn(SysBusDevice *dev)
     PPCE500PCIState *s;
     PCIBus *b;
     int i;
-    MemoryRegion *address_space = get_system_memory();
+    MemoryRegion *address_space_mem = get_system_memory();
+    MemoryRegion *address_space_io = get_system_io();
 
     h = FROM_SYSBUS(PCIHostState, sysbus_from_qdev(dev));
     s = DO_UPCAST(PPCE500PCIState, pci_state, h);
@@ -292,8 +293,8 @@ static int e500_pcihost_initfn(SysBusDevice *dev)
     }
 
     b = pci_register_bus(&s->pci_state.busdev.qdev, NULL, mpc85xx_pci_set_irq,
-                         mpc85xx_pci_map_irq, s->irq, address_space,
-                         PCI_DEVFN(0x11, 0), 4);
+                         mpc85xx_pci_map_irq, s->irq, address_space_mem,
+                         address_space_io, PCI_DEVFN(0x11, 0), 4);
     s->pci_state.bus = b;
 
     pci_create_simple(b, 0, "e500-host-bridge");
diff --git a/hw/prep_pci.c b/hw/prep_pci.c
index da02f0e..58619dd 100644
--- a/hw/prep_pci.c
+++ b/hw/prep_pci.c
@@ -110,7 +110,9 @@ static void prep_set_irq(void *opaque, int irq_num, int level)
     qemu_set_irq(pic[(irq_num & 1) ? 11 : 9] , level);
 }
 
-PCIBus *pci_prep_init(qemu_irq *pic, MemoryRegion *address_space)
+PCIBus *pci_prep_init(qemu_irq *pic,
+                      MemoryRegion *address_space_mem,
+                      MemoryRegion *address_space_io)
 {
     PREPPCIState *s;
     PCIDevice *d;
@@ -119,7 +121,9 @@ PCIBus *pci_prep_init(qemu_irq *pic, MemoryRegion *address_space)
     s = qemu_mallocz(sizeof(PREPPCIState));
     s->bus = pci_register_bus(NULL, "pci",
                               prep_set_irq, prep_map_irq, pic,
-                              address_space, 0, 4);
+                              address_space_mem,
+                              address_space_io,
+                              0, 4);
 
     pci_host_conf_register_ioport(0xcf8, s);
 
diff --git a/hw/prep_pci.h b/hw/prep_pci.h
index a27368b..b6b481a 100644
--- a/hw/prep_pci.h
+++ b/hw/prep_pci.h
@@ -4,6 +4,8 @@
 #include "qemu-common.h"
 #include "memory.h"
 
-PCIBus *pci_prep_init(qemu_irq *pic, MemoryRegion *address_space);
+PCIBus *pci_prep_init(qemu_irq *pic,
+                      MemoryRegion *address_space_mem,
+                      MemoryRegion *address_space_io);
 
 #endif
diff --git a/hw/sh_pci.c b/hw/sh_pci.c
index 0ef93a0..cd86501 100644
--- a/hw/sh_pci.c
+++ b/hw/sh_pci.c
@@ -128,7 +128,9 @@ static int sh_pci_init_device(SysBusDevice *dev)
     }
     s->bus = pci_register_bus(&s->busdev.qdev, "pci",
                               sh_pci_set_irq, sh_pci_map_irq,
-                              s->irq, get_system_memory(),
+                              s->irq,
+                              get_system_memory(),
+                              get_system_io(),
                               PCI_DEVFN(0, 0), 4);
     s->memconfig = cpu_register_io_memory(sh_pci_reg.r, sh_pci_reg.w,
                                           s, DEVICE_NATIVE_ENDIAN);
diff --git a/hw/unin_pci.c b/hw/unin_pci.c
index b499523..f896f8c 100644
--- a/hw/unin_pci.c
+++ b/hw/unin_pci.c
@@ -201,7 +201,9 @@ static int pci_unin_internal_init_device(SysBusDevice *dev)
     return 0;
 }
 
-PCIBus *pci_pmac_init(qemu_irq *pic, MemoryRegion *address_space)
+PCIBus *pci_pmac_init(qemu_irq *pic,
+                      MemoryRegion *address_space_mem,
+                      MemoryRegion *address_space_io)
 {
     DeviceState *dev;
     SysBusDevice *s;
@@ -215,7 +217,9 @@ PCIBus *pci_pmac_init(qemu_irq *pic, MemoryRegion *address_space)
     d = FROM_SYSBUS(UNINState, s);
     d->host_state.bus = pci_register_bus(&d->busdev.qdev, "pci",
                                          pci_unin_set_irq, pci_unin_map_irq,
-                                         pic, address_space,
+                                         pic,
+                                         address_space_mem,
+                                         address_space_io,
                                          PCI_DEVFN(11, 0), 4);
 
 #if 0
@@ -253,7 +257,9 @@ PCIBus *pci_pmac_init(qemu_irq *pic, MemoryRegion *address_space)
     return d->host_state.bus;
 }
 
-PCIBus *pci_pmac_u3_init(qemu_irq *pic, MemoryRegion *address_space)
+PCIBus *pci_pmac_u3_init(qemu_irq *pic,
+                         MemoryRegion *address_space_mem,
+                         MemoryRegion *address_space_io)
 {
     DeviceState *dev;
     SysBusDevice *s;
@@ -268,7 +274,9 @@ PCIBus *pci_pmac_u3_init(qemu_irq *pic, MemoryRegion *address_space)
 
     d->host_state.bus = pci_register_bus(&d->busdev.qdev, "pci",
                                          pci_unin_set_irq, pci_unin_map_irq,
-                                         pic, address_space,
+                                         pic,
+                                         address_space_mem,
+                                         address_space_io,
                                          PCI_DEVFN(11, 0), 4);
 
     sysbus_mmio_map(s, 0, 0xf0800000);
diff --git a/hw/versatile_pci.c b/hw/versatile_pci.c
index 6b693df..bf7fadd 100644
--- a/hw/versatile_pci.c
+++ b/hw/versatile_pci.c
@@ -112,7 +112,7 @@ static int pci_vpb_init(SysBusDevice *dev)
     }
     bus = pci_register_bus(&dev->qdev, "pci",
                            pci_vpb_set_irq, pci_vpb_map_irq, s->irq,
-                           get_system_memory(),
+                           get_system_memory(), get_system_io(),
                            PCI_DEVFN(11, 0), 4);
 
     /* ??? Register memory space.  */
