Patchwork [v4,05/15] apic: Introduce backend/frontend infrastructure for KVM reuse

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Submitter Jan Kiszka
Date Dec. 8, 2011, 11:52 a.m.
Message ID <47c0f31370bc9a2e7df3cd1fc3bb1908f7bd0975.1323345150.git.jan.kiszka@siemens.com>
Download mbox | patch
Permalink /patch/130146/
State New
Headers show

Comments

Jan Kiszka - Dec. 8, 2011, 11:52 a.m.
The KVM in-kernel APIC model will reuse parts of the user space model
while providing the same frontend view to guest and most management
interfaces. Introduce an APIC backend concept to encapsulate those
parts that will tell user space and KVM model apart. The backend offers
callback hooks for init, base/tpr setting, and the external NMI delivery
that will be implemented accordingly.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
---
 Makefile.target    |    2 +-
 hw/apic.c          |  282 +++-------------------------------------------------
 hw/apic_common.c   |  265 ++++++++++++++++++++++++++++++++++++++++++++++++
 hw/apic_internal.h |  119 ++++++++++++++++++++++
 hw/pc.c            |    1 +
 trace-events       |    2 +-
 6 files changed, 403 insertions(+), 268 deletions(-)
 create mode 100644 hw/apic_common.c
 create mode 100644 hw/apic_internal.h

Patch

diff --git a/Makefile.target b/Makefile.target
index 1d24a30..c46f062 100644
--- a/Makefile.target
+++ b/Makefile.target
@@ -231,7 +231,7 @@  obj-$(CONFIG_IVSHMEM) += ivshmem.o
 # Hardware support
 obj-i386-y += vga.o
 obj-i386-y += mc146818rtc.o pc.o
-obj-i386-y += cirrus_vga.o sga.o apic.o ioapic.o piix_pci.o
+obj-i386-y += cirrus_vga.o sga.o apic_common.o apic.o ioapic.o piix_pci.o
 obj-i386-y += vmport.o
 obj-i386-y += device-hotplug.o pci-hotplug.o smbios.o wdt_ib700.o
 obj-i386-y += debugcon.o multiboot.o
diff --git a/hw/apic.c b/hw/apic.c
index b9d733c..f25be80 100644
--- a/hw/apic.c
+++ b/hw/apic.c
@@ -16,53 +16,13 @@ 
  * You should have received a copy of the GNU Lesser General Public
  * License along with this library; if not, see <http://www.gnu.org/licenses/>
  */
-#include "hw.h"
+#include "apic_internal.h"
 #include "apic.h"
 #include "ioapic.h"
-#include "qemu-timer.h"
 #include "host-utils.h"
-#include "sysbus.h"
 #include "trace.h"
 #include "pc.h"
 
-/* APIC Local Vector Table */
-#define APIC_LVT_TIMER   0
-#define APIC_LVT_THERMAL 1
-#define APIC_LVT_PERFORM 2
-#define APIC_LVT_LINT0   3
-#define APIC_LVT_LINT1   4
-#define APIC_LVT_ERROR   5
-#define APIC_LVT_NB      6
-
-/* APIC delivery modes */
-#define APIC_DM_FIXED	0
-#define APIC_DM_LOWPRI	1
-#define APIC_DM_SMI	2
-#define APIC_DM_NMI	4
-#define APIC_DM_INIT	5
-#define APIC_DM_SIPI	6
-#define APIC_DM_EXTINT	7
-
-/* APIC destination mode */
-#define APIC_DESTMODE_FLAT	0xf
-#define APIC_DESTMODE_CLUSTER	1
-
-#define APIC_TRIGGER_EDGE  0
-#define APIC_TRIGGER_LEVEL 1
-
-#define	APIC_LVT_TIMER_PERIODIC		(1<<17)
-#define	APIC_LVT_MASKED			(1<<16)
-#define	APIC_LVT_LEVEL_TRIGGER		(1<<15)
-#define	APIC_LVT_REMOTE_IRR		(1<<14)
-#define	APIC_INPUT_POLARITY		(1<<13)
-#define	APIC_SEND_PENDING		(1<<12)
-
-#define ESR_ILLEGAL_ADDRESS (1 << 7)
-
-#define APIC_SV_DIRECTED_IO             (1<<12)
-#define APIC_SV_ENABLE                  (1<<8)
-
-#define MAX_APICS 255
 #define MAX_APIC_WORDS 8
 
 /* Intel APIC constants: from include/asm/msidef.h */
@@ -75,40 +35,7 @@ 
 #define MSI_ADDR_DEST_ID_SHIFT		12
 #define	MSI_ADDR_DEST_ID_MASK		0x00ffff0
 
-#define MSI_ADDR_SIZE                   0x100000
-
-typedef struct APICState APICState;
-
-struct APICState {
-    SysBusDevice busdev;
-    MemoryRegion io_memory;
-    void *cpu_env;
-    uint32_t apicbase;
-    uint8_t id;
-    uint8_t arb_id;
-    uint8_t tpr;
-    uint32_t spurious_vec;
-    uint8_t log_dest;
-    uint8_t dest_mode;
-    uint32_t isr[8];  /* in service register */
-    uint32_t tmr[8];  /* trigger mode register */
-    uint32_t irr[8]; /* interrupt request register */
-    uint32_t lvt[APIC_LVT_NB];
-    uint32_t esr; /* error register */
-    uint32_t icr[2];
-
-    uint32_t divide_conf;
-    int count_shift;
-    uint32_t initial_count;
-    int64_t initial_count_load_time, next_time;
-    uint32_t idx;
-    QEMUTimer *timer;
-    int sipi_vector;
-    int wait_for_sipi;
-};
-
 static APICState *local_apics[MAX_APICS + 1];
-static int apic_irq_delivered;
 
 static void apic_set_irq(APICState *s, int vector_num, int trigger_mode);
 static void apic_update_irq(APICState *s);
@@ -205,10 +132,8 @@  void apic_deliver_pic_intr(DeviceState *d, int level)
     }
 }
 
-void apic_deliver_nmi(DeviceState *d)
+static void apic_external_nmi(APICState *s)
 {
-    APICState *s = DO_UPCAST(APICState, busdev.qdev, d);
-
     apic_local_deliver(s, APIC_LVT_LINT1);
 }
 
@@ -300,14 +225,8 @@  void apic_deliver_irq(uint8_t dest, uint8_t dest_mode, uint8_t delivery_mode,
     apic_bus_deliver(deliver_bitmask, delivery_mode, vector_num, trigger_mode);
 }
 
-void cpu_set_apic_base(DeviceState *d, uint64_t val)
+static void apic_set_base(APICState *s, uint64_t val)
 {
-    APICState *s = DO_UPCAST(APICState, busdev.qdev, d);
-
-    trace_cpu_set_apic_base(val);
-
-    if (!s)
-        return;
     s->apicbase = (val & 0xfffff000) |
         (s->apicbase & (MSR_IA32_APICBASE_BSP | MSR_IA32_APICBASE_ENABLE));
     /* if disabled, cannot be enabled again */
@@ -318,32 +237,12 @@  void cpu_set_apic_base(DeviceState *d, uint64_t val)
     }
 }
 
-uint64_t cpu_get_apic_base(DeviceState *d)
+static void apic_set_tpr(APICState *s, uint8_t val)
 {
-    APICState *s = DO_UPCAST(APICState, busdev.qdev, d);
-
-    trace_cpu_get_apic_base(s ? (uint64_t)s->apicbase: 0);
-
-    return s ? s->apicbase : 0;
-}
-
-void cpu_set_apic_tpr(DeviceState *d, uint8_t val)
-{
-    APICState *s = DO_UPCAST(APICState, busdev.qdev, d);
-
-    if (!s)
-        return;
     s->tpr = (val & 0x0f) << 4;
     apic_update_irq(s);
 }
 
-uint8_t cpu_get_apic_tpr(DeviceState *d)
-{
-    APICState *s = DO_UPCAST(APICState, busdev.qdev, d);
-
-    return s ? s->tpr >> 4 : 0;
-}
-
 /* return -1 if no bit is set */
 static int get_highest_priority_int(uint32_t *tab)
 {
@@ -413,25 +312,9 @@  static void apic_update_irq(APICState *s)
     }
 }
 
-void apic_reset_irq_delivered(void)
-{
-    trace_apic_reset_irq_delivered(apic_irq_delivered);
-
-    apic_irq_delivered = 0;
-}
-
-int apic_get_irq_delivered(void)
-{
-    trace_apic_get_irq_delivered(apic_irq_delivered);
-
-    return apic_irq_delivered;
-}
-
 static void apic_set_irq(APICState *s, int vector_num, int trigger_mode)
 {
-    apic_irq_delivered += !get_bit(s->irr, vector_num);
-
-    trace_apic_set_irq(apic_irq_delivered);
+    apic_set_irq_delivered(!get_bit(s->irr, vector_num));
 
     set_bit(s->irr, vector_num);
     if (trigger_mode)
@@ -510,35 +393,6 @@  static void apic_get_delivery_bitmask(uint32_t *deliver_bitmask,
     }
 }
 
-void apic_init_reset(DeviceState *d)
-{
-    APICState *s = DO_UPCAST(APICState, busdev.qdev, d);
-    int i;
-
-    if (!s)
-        return;
-
-    s->tpr = 0;
-    s->spurious_vec = 0xff;
-    s->log_dest = 0;
-    s->dest_mode = 0xf;
-    memset(s->isr, 0, sizeof(s->isr));
-    memset(s->tmr, 0, sizeof(s->tmr));
-    memset(s->irr, 0, sizeof(s->irr));
-    for(i = 0; i < APIC_LVT_NB; i++)
-        s->lvt[i] = 1 << 16; /* mask LVT */
-    s->esr = 0;
-    memset(s->icr, 0, sizeof(s->icr));
-    s->divide_conf = 0;
-    s->count_shift = 0;
-    s->initial_count = 0;
-    s->initial_count_load_time = 0;
-    s->next_time = 0;
-    s->wait_for_sipi = 1;
-
-    qemu_del_timer(s->timer);
-}
-
 static void apic_startup(APICState *s, int vector_num)
 {
     s->sipi_vector = vector_num;
@@ -899,96 +753,6 @@  static void apic_mem_writel(void *opaque, target_phys_addr_t addr, uint32_t val)
     }
 }
 
-/* This function is only used for old state version 1 and 2 */
-static int apic_load_old(QEMUFile *f, void *opaque, int version_id)
-{
-    APICState *s = opaque;
-    int i;
-
-    if (version_id > 2)
-        return -EINVAL;
-
-    /* XXX: what if the base changes? (registered memory regions) */
-    qemu_get_be32s(f, &s->apicbase);
-    qemu_get_8s(f, &s->id);
-    qemu_get_8s(f, &s->arb_id);
-    qemu_get_8s(f, &s->tpr);
-    qemu_get_be32s(f, &s->spurious_vec);
-    qemu_get_8s(f, &s->log_dest);
-    qemu_get_8s(f, &s->dest_mode);
-    for (i = 0; i < 8; i++) {
-        qemu_get_be32s(f, &s->isr[i]);
-        qemu_get_be32s(f, &s->tmr[i]);
-        qemu_get_be32s(f, &s->irr[i]);
-    }
-    for (i = 0; i < APIC_LVT_NB; i++) {
-        qemu_get_be32s(f, &s->lvt[i]);
-    }
-    qemu_get_be32s(f, &s->esr);
-    qemu_get_be32s(f, &s->icr[0]);
-    qemu_get_be32s(f, &s->icr[1]);
-    qemu_get_be32s(f, &s->divide_conf);
-    s->count_shift=qemu_get_be32(f);
-    qemu_get_be32s(f, &s->initial_count);
-    s->initial_count_load_time=qemu_get_be64(f);
-    s->next_time=qemu_get_be64(f);
-
-    if (version_id >= 2)
-        qemu_get_timer(f, s->timer);
-    return 0;
-}
-
-static const VMStateDescription vmstate_apic = {
-    .name = "apic",
-    .version_id = 3,
-    .minimum_version_id = 3,
-    .minimum_version_id_old = 1,
-    .load_state_old = apic_load_old,
-    .fields      = (VMStateField []) {
-        VMSTATE_UINT32(apicbase, APICState),
-        VMSTATE_UINT8(id, APICState),
-        VMSTATE_UINT8(arb_id, APICState),
-        VMSTATE_UINT8(tpr, APICState),
-        VMSTATE_UINT32(spurious_vec, APICState),
-        VMSTATE_UINT8(log_dest, APICState),
-        VMSTATE_UINT8(dest_mode, APICState),
-        VMSTATE_UINT32_ARRAY(isr, APICState, 8),
-        VMSTATE_UINT32_ARRAY(tmr, APICState, 8),
-        VMSTATE_UINT32_ARRAY(irr, APICState, 8),
-        VMSTATE_UINT32_ARRAY(lvt, APICState, APIC_LVT_NB),
-        VMSTATE_UINT32(esr, APICState),
-        VMSTATE_UINT32_ARRAY(icr, APICState, 2),
-        VMSTATE_UINT32(divide_conf, APICState),
-        VMSTATE_INT32(count_shift, APICState),
-        VMSTATE_UINT32(initial_count, APICState),
-        VMSTATE_INT64(initial_count_load_time, APICState),
-        VMSTATE_INT64(next_time, APICState),
-        VMSTATE_TIMER(timer, APICState),
-        VMSTATE_END_OF_LIST()
-    }
-};
-
-static void apic_reset(DeviceState *d)
-{
-    APICState *s = DO_UPCAST(APICState, busdev.qdev, d);
-    int bsp;
-
-    bsp = cpu_is_bsp(s->cpu_env);
-    s->apicbase = 0xfee00000 |
-        (bsp ? MSR_IA32_APICBASE_BSP : 0) | MSR_IA32_APICBASE_ENABLE;
-
-    apic_init_reset(d);
-
-    if (bsp) {
-        /*
-         * LINT0 delivery mode on CPU #0 is set to ExtInt at initialization
-         * time typically by BIOS, so PIC interrupt can be delivered to the
-         * processor when local APIC is enabled.
-         */
-        s->lvt[APIC_LVT_LINT0] = 0x700;
-    }
-}
-
 static const MemoryRegionOps apic_io_ops = {
     .old_mmio = {
         .read = { apic_mem_readb, apic_mem_readw, apic_mem_readl, },
@@ -997,41 +761,27 @@  static const MemoryRegionOps apic_io_ops = {
     .endianness = DEVICE_NATIVE_ENDIAN,
 };
 
-static int apic_init1(SysBusDevice *dev)
+static void apic_backend_init(APICState *s)
 {
-    APICState *s = FROM_SYSBUS(APICState, dev);
-    static int last_apic_idx;
-
-    if (last_apic_idx >= MAX_APICS) {
-        return -1;
-    }
-    memory_region_init_io(&s->io_memory, &apic_io_ops, s, "apic",
-                          MSI_ADDR_SIZE);
-    sysbus_init_mmio(dev, &s->io_memory);
+    memory_region_init_io(&s->io_memory, &apic_io_ops, s, "apic-msi",
+                          MSI_SPACE_SIZE);
 
     s->timer = qemu_new_timer_ns(vm_clock, apic_timer, s);
-    s->idx = last_apic_idx++;
     local_apics[s->idx] = s;
-    return 0;
 }
 
-static SysBusDeviceInfo apic_info = {
-    .init = apic_init1,
-    .qdev.name = "apic",
-    .qdev.size = sizeof(APICState),
-    .qdev.vmsd = &vmstate_apic,
-    .qdev.reset = apic_reset,
-    .qdev.no_user = 1,
-    .qdev.props = (Property[]) {
-        DEFINE_PROP_UINT8("id", APICState, id, -1),
-        DEFINE_PROP_PTR("cpu_env", APICState, cpu_env),
-        DEFINE_PROP_END_OF_LIST(),
-    }
+static APICBackend apic_backend = {
+    .name = "QEMU",
+    .init = apic_backend_init,
+    .set_base = apic_set_base,
+    .set_tpr = apic_set_tpr,
+    .external_nmi = apic_external_nmi,
 };
 
 static void apic_register_devices(void)
 {
-    sysbus_register_withprop(&apic_info);
+    apic_register_device();
+    apic_register_backend(&apic_backend);
 }
 
 device_init(apic_register_devices)
diff --git a/hw/apic_common.c b/hw/apic_common.c
new file mode 100644
index 0000000..73241e4
--- /dev/null
+++ b/hw/apic_common.c
@@ -0,0 +1,265 @@ 
+/*
+ *  APIC support - common bits of emulated and KVM kernel model
+ *
+ *  Copyright (c) 2004-2005 Fabrice Bellard
+ *  Copyright (c) 2011      Jan Kiszka, Siemens AG
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>
+ */
+#include "apic.h"
+#include "apic_internal.h"
+#include "trace.h"
+
+static QSIMPLEQ_HEAD(, APICBackend) backends =
+    QSIMPLEQ_HEAD_INITIALIZER(backends);
+static int apic_irq_delivered;
+
+void cpu_set_apic_base(DeviceState *d, uint64_t val)
+{
+    APICState *s = DO_UPCAST(APICState, busdev.qdev, d);
+
+    trace_cpu_set_apic_base(val);
+
+    if (s) {
+        s->backend->set_base(s, val);
+    }
+}
+
+uint64_t cpu_get_apic_base(DeviceState *d)
+{
+    APICState *s = DO_UPCAST(APICState, busdev.qdev, d);
+
+    trace_cpu_get_apic_base(s ? (uint64_t)s->apicbase : 0);
+
+    return s ? s->apicbase : 0;
+}
+
+void cpu_set_apic_tpr(DeviceState *d, uint8_t val)
+{
+    APICState *s = DO_UPCAST(APICState, busdev.qdev, d);
+
+    if (s) {
+        s->backend->set_tpr(s, val);
+    }
+}
+
+uint8_t cpu_get_apic_tpr(DeviceState *d)
+{
+    APICState *s = DO_UPCAST(APICState, busdev.qdev, d);
+
+    return s ? s->tpr >> 4 : 0;
+}
+
+void apic_set_irq_delivered(int delivered)
+{
+    apic_irq_delivered += delivered;
+
+    trace_apic_set_irq_delivered(apic_irq_delivered);
+}
+
+void apic_reset_irq_delivered(void)
+{
+    trace_apic_reset_irq_delivered(apic_irq_delivered);
+
+    apic_irq_delivered = false;
+}
+
+int apic_get_irq_delivered(void)
+{
+    trace_apic_get_irq_delivered(apic_irq_delivered);
+
+    return apic_irq_delivered;
+}
+
+void apic_deliver_nmi(DeviceState *d)
+{
+    APICState *s = DO_UPCAST(APICState, busdev.qdev, d);
+
+    s->backend->external_nmi(s);
+}
+
+void apic_init_reset(DeviceState *d)
+{
+    APICState *s = DO_UPCAST(APICState, busdev.qdev, d);
+    int i;
+
+    if (!s) {
+        return;
+    }
+    s->tpr = 0;
+    s->spurious_vec = 0xff;
+    s->log_dest = 0;
+    s->dest_mode = 0xf;
+    memset(s->isr, 0, sizeof(s->isr));
+    memset(s->tmr, 0, sizeof(s->tmr));
+    memset(s->irr, 0, sizeof(s->irr));
+    for (i = 0; i < APIC_LVT_NB; i++) {
+        s->lvt[i] = APIC_LVT_MASKED;
+    }
+    s->esr = 0;
+    memset(s->icr, 0, sizeof(s->icr));
+    s->divide_conf = 0;
+    s->count_shift = 0;
+    s->initial_count = 0;
+    s->initial_count_load_time = 0;
+    s->next_time = 0;
+    s->wait_for_sipi = 1;
+
+    qemu_del_timer(s->timer);
+}
+
+static void apic_reset(DeviceState *d)
+{
+    APICState *s = DO_UPCAST(APICState, busdev.qdev, d);
+    bool bsp;
+
+    bsp = cpu_is_bsp(s->cpu_env);
+    s->apicbase = 0xfee00000 |
+        (bsp ? MSR_IA32_APICBASE_BSP : 0) | MSR_IA32_APICBASE_ENABLE;
+
+    apic_init_reset(d);
+
+    if (bsp) {
+        /*
+         * LINT0 delivery mode on CPU #0 is set to ExtInt at initialization
+         * time typically by BIOS, so PIC interrupt can be delivered to the
+         * processor when local APIC is enabled.
+         */
+        s->lvt[APIC_LVT_LINT0] = 0x700;
+    }
+}
+
+/* This function is only used for old state version 1 and 2 */
+static int apic_load_old(QEMUFile *f, void *opaque, int version_id)
+{
+    APICState *s = opaque;
+    int i;
+
+    if (version_id > 2) {
+        return -EINVAL;
+    }
+
+    /* XXX: what if the base changes? (registered memory regions) */
+    qemu_get_be32s(f, &s->apicbase);
+    qemu_get_8s(f, &s->id);
+    qemu_get_8s(f, &s->arb_id);
+    qemu_get_8s(f, &s->tpr);
+    qemu_get_be32s(f, &s->spurious_vec);
+    qemu_get_8s(f, &s->log_dest);
+    qemu_get_8s(f, &s->dest_mode);
+    for (i = 0; i < 8; i++) {
+        qemu_get_be32s(f, &s->isr[i]);
+        qemu_get_be32s(f, &s->tmr[i]);
+        qemu_get_be32s(f, &s->irr[i]);
+    }
+    for (i = 0; i < APIC_LVT_NB; i++) {
+        qemu_get_be32s(f, &s->lvt[i]);
+    }
+    qemu_get_be32s(f, &s->esr);
+    qemu_get_be32s(f, &s->icr[0]);
+    qemu_get_be32s(f, &s->icr[1]);
+    qemu_get_be32s(f, &s->divide_conf);
+    s->count_shift = qemu_get_be32(f);
+    qemu_get_be32s(f, &s->initial_count);
+    s->initial_count_load_time = qemu_get_be64(f);
+    s->next_time = qemu_get_be64(f);
+
+    if (version_id >= 2) {
+        qemu_get_timer(f, s->timer);
+    }
+    return 0;
+}
+
+static const VMStateDescription vmstate_apic = {
+    .name = "apic",
+    .version_id = 3,
+    .minimum_version_id = 3,
+    .minimum_version_id_old = 1,
+    .load_state_old = apic_load_old,
+    .fields      = (VMStateField[]) {
+        VMSTATE_UINT32(apicbase, APICState),
+        VMSTATE_UINT8(id, APICState),
+        VMSTATE_UINT8(arb_id, APICState),
+        VMSTATE_UINT8(tpr, APICState),
+        VMSTATE_UINT32(spurious_vec, APICState),
+        VMSTATE_UINT8(log_dest, APICState),
+        VMSTATE_UINT8(dest_mode, APICState),
+        VMSTATE_UINT32_ARRAY(isr, APICState, 8),
+        VMSTATE_UINT32_ARRAY(tmr, APICState, 8),
+        VMSTATE_UINT32_ARRAY(irr, APICState, 8),
+        VMSTATE_UINT32_ARRAY(lvt, APICState, APIC_LVT_NB),
+        VMSTATE_UINT32(esr, APICState),
+        VMSTATE_UINT32_ARRAY(icr, APICState, 2),
+        VMSTATE_UINT32(divide_conf, APICState),
+        VMSTATE_INT32(count_shift, APICState),
+        VMSTATE_UINT32(initial_count, APICState),
+        VMSTATE_INT64(initial_count_load_time, APICState),
+        VMSTATE_INT64(next_time, APICState),
+        VMSTATE_TIMER(timer, APICState),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static int apic_init(SysBusDevice *dev)
+{
+    APICState *s = FROM_SYSBUS(APICState, dev);
+    static int apic_no;
+    APICBackend *b;
+
+    if (apic_no >= MAX_APICS) {
+        return -1;
+    }
+    s->idx = apic_no++;
+
+    QSIMPLEQ_FOREACH(b, &backends, entry) {
+        if (strcmp(b->name, s->backend_name) == 0) {
+            s->backend = b;
+            break;
+        }
+    }
+    if (!s->backend) {
+        hw_error("APIC backend '%s' not found!", s->backend_name);
+        exit(1);
+    }
+
+    b->init(s);
+
+    sysbus_init_mmio(&s->busdev, &s->io_memory);
+    return 0;
+}
+
+static SysBusDeviceInfo apic_info = {
+    .init = apic_init,
+    .qdev.name = "apic",
+    .qdev.size = sizeof(APICState),
+    .qdev.vmsd = &vmstate_apic,
+    .qdev.reset = apic_reset,
+    .qdev.no_user = 1,
+    .qdev.props = (Property[]) {
+        DEFINE_PROP_UINT8("id", APICState, id, -1),
+        DEFINE_PROP_PTR("cpu_env", APICState, cpu_env),
+        DEFINE_PROP_STRING("backend", APICState, backend_name),
+        DEFINE_PROP_END_OF_LIST(),
+    }
+};
+
+void apic_register_backend(APICBackend *backend)
+{
+    QSIMPLEQ_INSERT_TAIL(&backends, backend, entry);
+}
+
+void apic_register_device(void)
+{
+    sysbus_register_withprop(&apic_info);
+}
diff --git a/hw/apic_internal.h b/hw/apic_internal.h
new file mode 100644
index 0000000..80d6e62
--- /dev/null
+++ b/hw/apic_internal.h
@@ -0,0 +1,119 @@ 
+/*
+ *  APIC support - internal interfaces
+ *
+ *  Copyright (c) 2004-2005 Fabrice Bellard
+ *  Copyright (c) 2011      Jan Kiszka, Siemens AG
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>
+ */
+#ifndef QEMU_APIC_INTERNAL_H
+#define QEMU_APIC_INTERNAL_H
+
+#include "memory.h"
+#include "sysbus.h"
+#include "qemu-timer.h"
+#include "qemu-queue.h"
+
+/* APIC Local Vector Table */
+#define APIC_LVT_TIMER                  0
+#define APIC_LVT_THERMAL                1
+#define APIC_LVT_PERFORM                2
+#define APIC_LVT_LINT0                  3
+#define APIC_LVT_LINT1                  4
+#define APIC_LVT_ERROR                  5
+#define APIC_LVT_NB                     6
+
+/* APIC delivery modes */
+#define APIC_DM_FIXED                   0
+#define APIC_DM_LOWPRI                  1
+#define APIC_DM_SMI                     2
+#define APIC_DM_NMI                     4
+#define APIC_DM_INIT                    5
+#define APIC_DM_SIPI                    6
+#define APIC_DM_EXTINT                  7
+
+/* APIC destination mode */
+#define APIC_DESTMODE_FLAT              0xf
+#define APIC_DESTMODE_CLUSTER           1
+
+#define APIC_TRIGGER_EDGE               0
+#define APIC_TRIGGER_LEVEL              1
+
+#define APIC_LVT_TIMER_PERIODIC         (1<<17)
+#define APIC_LVT_MASKED                 (1<<16)
+#define APIC_LVT_LEVEL_TRIGGER          (1<<15)
+#define APIC_LVT_REMOTE_IRR             (1<<14)
+#define APIC_INPUT_POLARITY             (1<<13)
+#define APIC_SEND_PENDING               (1<<12)
+
+#define ESR_ILLEGAL_ADDRESS (1 << 7)
+
+#define APIC_SV_DIRECTED_IO             (1<<12)
+#define APIC_SV_ENABLE                  (1<<8)
+
+#define MAX_APICS 255
+
+#define MSI_SPACE_SIZE                  0x100000
+
+typedef struct APICBackend APICBackend;
+typedef struct APICState APICState;
+
+struct APICBackend {
+    const char *name;
+    void (*init)(APICState *s);
+    void (*set_base)(APICState *s, uint64_t val);
+    void (*set_tpr)(APICState *s, uint8_t val);
+    void (*external_nmi)(APICState *s);
+
+    QSIMPLEQ_ENTRY(APICBackend) entry;
+};
+
+struct APICState {
+    SysBusDevice busdev;
+    MemoryRegion io_memory;
+    void *cpu_env;
+    uint32_t apicbase;
+    uint8_t id;
+    uint8_t arb_id;
+    uint8_t tpr;
+    uint32_t spurious_vec;
+    uint8_t log_dest;
+    uint8_t dest_mode;
+    uint32_t isr[8];  /* in service register */
+    uint32_t tmr[8];  /* trigger mode register */
+    uint32_t irr[8]; /* interrupt request register */
+    uint32_t lvt[APIC_LVT_NB];
+    uint32_t esr; /* error register */
+    uint32_t icr[2];
+
+    uint32_t divide_conf;
+    int count_shift;
+    uint32_t initial_count;
+    int64_t initial_count_load_time;
+    int64_t next_time;
+    int idx;
+    QEMUTimer *timer;
+    int sipi_vector;
+    int wait_for_sipi;
+
+    char *backend_name;
+    APICBackend *backend;
+};
+
+void apic_register_device(void);
+void apic_register_backend(APICBackend *backend);
+
+void apic_set_irq_delivered(int delivered);
+
+#endif /* !QEMU_APIC_INTERNAL_H */
diff --git a/hw/pc.c b/hw/pc.c
index 240aaae..ee6e59b 100644
--- a/hw/pc.c
+++ b/hw/pc.c
@@ -884,6 +884,7 @@  static DeviceState *apic_init(void *env, uint8_t apic_id)
     dev = qdev_create(NULL, "apic");
     qdev_prop_set_uint8(dev, "id", apic_id);
     qdev_prop_set_ptr(dev, "cpu_env", env);
+    qdev_prop_set_string(dev, "backend", g_strdup("QEMU"));
     qdev_init_nofail(dev);
     d = sysbus_from_qdev(dev);
 
diff --git a/trace-events b/trace-events
index 962caca..210ee66 100644
--- a/trace-events
+++ b/trace-events
@@ -98,7 +98,7 @@  apic_mem_writel(uint64_t addr, uint32_t val) "%"PRIx64" = %08x"
 # coalescing
 apic_reset_irq_delivered(int apic_irq_delivered) "old coalescing %d"
 apic_get_irq_delivered(int apic_irq_delivered) "returning coalescing %d"
-apic_set_irq(int apic_irq_delivered) "coalescing %d"
+apic_set_irq_delivered(int apic_irq_delivered) "coalescing %d"
 
 # hw/cs4231.c
 cs4231_mem_readl_dreg(uint32_t reg, uint32_t ret) "read dreg %d: 0x%02x"