diff --git a/Makefile.target b/Makefile.target
index 29fde6e..4b460fd 100644
--- a/Makefile.target
+++ b/Makefile.target
@@ -236,7 +236,8 @@ obj-y += device-hotplug.o
 
 # Hardware support
 obj-i386-y += mc146818rtc.o pc.o
-obj-i386-y += sga.o apic_common.o apic.o ioapic_common.o ioapic.o piix_pci.o
+obj-i386-y += apic_common.o apic.o kvmvapic.o
+obj-i386-y += sga.o ioapic_common.o ioapic.o piix_pci.o
 obj-i386-y += vmport.o
 obj-i386-y += 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 ff9d24e..4eeaf88 100644
--- a/hw/apic.c
+++ b/hw/apic.c
@@ -35,6 +35,10 @@
 #define MSI_ADDR_DEST_ID_SHIFT		12
 #define	MSI_ADDR_DEST_ID_MASK		0x00ffff0
 
+#define SYNC_FROM_VAPIC                 0x1
+#define SYNC_TO_VAPIC                   0x2
+#define SYNC_ISR_IRR_TO_VAPIC           0x4
+
 static APICCommonState *local_apics[MAX_APICS + 1];
 
 static void apic_set_irq(APICCommonState *s, int vector_num, int trigger_mode);
@@ -78,6 +82,70 @@ static inline int get_bit(uint32_t *tab, int index)
     return !!(tab[i] & mask);
 }
 
+/* return -1 if no bit is set */
+static int get_highest_priority_int(uint32_t *tab)
+{
+    int i;
+    for (i = 7; i >= 0; i--) {
+        if (tab[i] != 0) {
+            return i * 32 + fls_bit(tab[i]);
+        }
+    }
+    return -1;
+}
+
+static void apic_sync_vapic(APICCommonState *s, int sync_type)
+{
+    VAPICState vapic_state;
+    size_t length;
+    off_t start;
+    int vector;
+
+    if (!s->vapic_paddr) {
+        return;
+    }
+    if (sync_type & SYNC_FROM_VAPIC) {
+        cpu_physical_memory_rw(s->vapic_paddr, (void *)&vapic_state,
+                               sizeof(vapic_state), 0);
+        s->tpr = vapic_state.tpr;
+    }
+    if (sync_type & (SYNC_TO_VAPIC | SYNC_ISR_IRR_TO_VAPIC)) {
+        start = offsetof(VAPICState, isr);
+        length = offsetof(VAPICState, enabled) - offsetof(VAPICState, isr);
+
+        if (sync_type & SYNC_TO_VAPIC) {
+            assert(qemu_cpu_is_self(s->cpu_env));
+
+            vapic_state.tpr = s->tpr;
+            vapic_state.enabled = 1;
+            start = 0;
+            length = sizeof(VAPICState);
+        }
+
+        vector = get_highest_priority_int(s->isr);
+        if (vector < 0) {
+            vector = 0;
+        }
+        vapic_state.isr = vector & 0xf0;
+
+        vapic_state.zero = 0;
+
+        vector = get_highest_priority_int(s->irr);
+        if (vector < 0) {
+            vector = 0;
+        }
+        vapic_state.irr = vector & 0xff;
+
+        cpu_physical_memory_write_rom(s->vapic_paddr + start,
+                                      ((void *)&vapic_state) + start, length);
+    }
+}
+
+static void apic_vapic_base_update(APICCommonState *s)
+{
+    apic_sync_vapic(s, SYNC_TO_VAPIC);
+}
+
 static void apic_local_deliver(APICCommonState *s, int vector)
 {
     uint32_t lvt = s->lvt[vector];
@@ -239,20 +307,17 @@ static void apic_set_base(APICCommonState *s, uint64_t val)
 
 static void apic_set_tpr(APICCommonState *s, uint8_t val)
 {
-    s->tpr = (val & 0x0f) << 4;
-    apic_update_irq(s);
+    /* Updates from cr8 are ignored while the VAPIC is active */
+    if (!s->vapic_paddr) {
+        s->tpr = val << 4;
+        apic_update_irq(s);
+    }
 }
 
-/* return -1 if no bit is set */
-static int get_highest_priority_int(uint32_t *tab)
+static uint8_t apic_get_tpr(APICCommonState *s)
 {
-    int i;
-    for(i = 7; i >= 0; i--) {
-        if (tab[i] != 0) {
-            return i * 32 + fls_bit(tab[i]);
-        }
-    }
-    return -1;
+    apic_sync_vapic(s, SYNC_FROM_VAPIC);
+    return s->tpr >> 4;
 }
 
 static int apic_get_ppr(APICCommonState *s)
@@ -312,6 +377,14 @@ static void apic_update_irq(APICCommonState *s)
     }
 }
 
+void apic_poll_irq(DeviceState *d)
+{
+    APICCommonState *s = APIC_COMMON(d);
+
+    apic_sync_vapic(s, SYNC_FROM_VAPIC);
+    apic_update_irq(s);
+}
+
 static void apic_set_irq(APICCommonState *s, int vector_num, int trigger_mode)
 {
     apic_report_irq_delivered(!get_bit(s->irr, vector_num));
@@ -321,6 +394,16 @@ static void apic_set_irq(APICCommonState *s, int vector_num, int trigger_mode)
         set_bit(s->tmr, vector_num);
     else
         reset_bit(s->tmr, vector_num);
+    if (s->vapic_paddr) {
+        apic_sync_vapic(s, SYNC_ISR_IRR_TO_VAPIC);
+        /*
+         * The vcpu thread needs to see the new IRR before we pull its current
+         * TPR value. That way, if we miss a lowering of the TRP, the guest
+         * has the chance to notice the new IRR and poll for IRQs on its own.
+         */
+        smp_wmb();
+        apic_sync_vapic(s, SYNC_FROM_VAPIC);
+    }
     apic_update_irq(s);
 }
 
@@ -334,6 +417,7 @@ static void apic_eoi(APICCommonState *s)
     if (!(s->spurious_vec & APIC_SV_DIRECTED_IO) && get_bit(s->tmr, isrv)) {
         ioapic_eoi_broadcast(isrv);
     }
+    apic_sync_vapic(s, SYNC_FROM_VAPIC | SYNC_TO_VAPIC);
     apic_update_irq(s);
 }
 
@@ -471,15 +555,19 @@ int apic_get_interrupt(DeviceState *d)
     if (!(s->spurious_vec & APIC_SV_ENABLE))
         return -1;
 
+    apic_sync_vapic(s, SYNC_FROM_VAPIC);
     intno = apic_irq_pending(s);
 
     if (intno == 0) {
+        apic_sync_vapic(s, SYNC_TO_VAPIC);
         return -1;
     } else if (intno < 0) {
+        apic_sync_vapic(s, SYNC_TO_VAPIC);
         return s->spurious_vec & 0xff;
     }
     reset_bit(s->irr, intno);
     set_bit(s->isr, intno);
+    apic_sync_vapic(s, SYNC_TO_VAPIC);
     apic_update_irq(s);
     return intno;
 }
@@ -576,6 +664,10 @@ static uint32_t apic_mem_readl(void *opaque, target_phys_addr_t addr)
         val = 0x11 | ((APIC_LVT_NB - 1) << 16); /* version 0x11 */
         break;
     case 0x08:
+        apic_sync_vapic(s, SYNC_FROM_VAPIC);
+        if (apic_report_tpr_access) {
+            cpu_report_tpr_access(s->cpu_env, TPR_ACCESS_READ);
+        }
         val = s->tpr;
         break;
     case 0x09:
@@ -675,7 +767,11 @@ static void apic_mem_writel(void *opaque, target_phys_addr_t addr, uint32_t val)
     case 0x03:
         break;
     case 0x08:
+        if (apic_report_tpr_access) {
+            cpu_report_tpr_access(s->cpu_env, TPR_ACCESS_WRITE);
+        }
         s->tpr = val;
+        apic_sync_vapic(s, SYNC_TO_VAPIC);
         apic_update_irq(s);
         break;
     case 0x09:
@@ -737,6 +833,11 @@ static void apic_mem_writel(void *opaque, target_phys_addr_t addr, uint32_t val)
     }
 }
 
+static void apic_pre_save(APICCommonState *s)
+{
+    apic_sync_vapic(s, SYNC_FROM_VAPIC);
+}
+
 static void apic_post_load(APICCommonState *s)
 {
     if (s->timer_expiry != -1) {
@@ -770,7 +871,10 @@ static void apic_class_init(ObjectClass *klass, void *data)
     k->init = apic_init;
     k->set_base = apic_set_base;
     k->set_tpr = apic_set_tpr;
+    k->get_tpr = apic_get_tpr;
+    k->vapic_base_update = apic_vapic_base_update;
     k->external_nmi = apic_external_nmi;
+    k->pre_save = apic_pre_save;
     k->post_load = apic_post_load;
 }
 
diff --git a/hw/apic_common.c b/hw/apic_common.c
index 340d793..60b8259 100644
--- a/hw/apic_common.c
+++ b/hw/apic_common.c
@@ -20,8 +20,10 @@
 #include "apic.h"
 #include "apic_internal.h"
 #include "trace.h"
+#include "kvm.h"
 
 static int apic_irq_delivered;
+bool apic_report_tpr_access;
 
 void cpu_set_apic_base(DeviceState *d, uint64_t val)
 {
@@ -63,14 +65,45 @@ void cpu_set_apic_tpr(DeviceState *d, uint8_t val)
 
 uint8_t cpu_get_apic_tpr(DeviceState *d)
 {
+    APICCommonState *s;
+    APICCommonClass *info;
+
+    if (!d) {
+        return 0;
+    }
+
+    s = APIC_COMMON(d);
+    info = APIC_COMMON_GET_CLASS(s);
+
+    return info->get_tpr(s);
+}
+
+void apic_enable_tpr_access_reporting(DeviceState *d, bool enable)
+{
+    APICCommonState *s = DO_UPCAST(APICCommonState, busdev.qdev, d);
+    APICCommonClass *info = APIC_COMMON_GET_CLASS(s);
+
+    apic_report_tpr_access = enable;
+    if (info->enable_tpr_reporting) {
+        info->enable_tpr_reporting(s, enable);
+    }
+}
+
+void apic_enable_vapic(DeviceState *d, target_phys_addr_t paddr)
+{
     APICCommonState *s = DO_UPCAST(APICCommonState, busdev.qdev, d);
+    APICCommonClass *info = APIC_COMMON_GET_CLASS(s);
 
-    return s ? s->tpr >> 4 : 0;
+    s->vapic_paddr = paddr;
+    info->vapic_base_update(s);
 }
 
 void apic_handle_tpr_access_report(DeviceState *d, target_ulong ip,
                                    TPRAccess access)
 {
+    APICCommonState *s = DO_UPCAST(APICCommonState, busdev.qdev, d);
+
+    vapic_report_tpr_access(s->vapic, s->cpu_env, ip, access);
 }
 
 void apic_report_irq_delivered(int delivered)
@@ -171,12 +204,16 @@ void apic_init_reset(DeviceState *d)
 static void apic_reset_common(DeviceState *d)
 {
     APICCommonState *s = DO_UPCAST(APICCommonState, busdev.qdev, d);
+    APICCommonClass *info = APIC_COMMON_GET_CLASS(s);
     bool bsp;
 
     bsp = cpu_is_bsp(s->cpu_env);
     s->apicbase = 0xfee00000 |
         (bsp ? MSR_IA32_APICBASE_BSP : 0) | MSR_IA32_APICBASE_ENABLE;
 
+    s->vapic_paddr = 0;
+    info->vapic_base_update(s);
+
     apic_init_reset(d);
 
     if (bsp) {
@@ -239,6 +276,7 @@ static int apic_init_common(SysBusDevice *dev)
 {
     APICCommonState *s = APIC_COMMON(dev);
     APICCommonClass *info;
+    static DeviceState *vapic;
     static int apic_no;
 
     if (apic_no >= MAX_APICS) {
@@ -249,10 +287,29 @@ static int apic_init_common(SysBusDevice *dev)
     info = APIC_COMMON_GET_CLASS(s);
     info->init(s);
 
-    sysbus_init_mmio(&s->busdev, &s->io_memory);
+    sysbus_init_mmio(dev, &s->io_memory);
+
+    if (!vapic && s->vapic_control & VAPIC_ENABLE_MASK) {
+        vapic = sysbus_create_simple("kvmvapic", -1, NULL);
+    }
+    s->vapic = vapic;
+    if (apic_report_tpr_access && info->enable_tpr_reporting) {
+        info->enable_tpr_reporting(s, true);
+    }
+
     return 0;
 }
 
+static void apic_dispatch_pre_save(void *opaque)
+{
+    APICCommonState *s = APIC_COMMON(opaque);
+    APICCommonClass *info = APIC_COMMON_GET_CLASS(s);
+
+    if (info->pre_save) {
+        info->pre_save(s);
+    }
+}
+
 static int apic_dispatch_post_load(void *opaque, int version_id)
 {
     APICCommonState *s = APIC_COMMON(opaque);
@@ -270,6 +327,7 @@ static const VMStateDescription vmstate_apic_common = {
     .minimum_version_id = 3,
     .minimum_version_id_old = 1,
     .load_state_old = apic_load_old,
+    .pre_save = apic_dispatch_pre_save,
     .post_load = apic_dispatch_post_load,
     .fields = (VMStateField[]) {
         VMSTATE_UINT32(apicbase, APICCommonState),
@@ -299,6 +357,8 @@ static const VMStateDescription vmstate_apic_common = {
 static Property apic_properties_common[] = {
     DEFINE_PROP_UINT8("id", APICCommonState, id, -1),
     DEFINE_PROP_PTR("cpu_env", APICCommonState, cpu_env),
+    DEFINE_PROP_BIT("vapic", APICCommonState, vapic_control, VAPIC_ENABLE_BIT,
+                    true),
     DEFINE_PROP_END_OF_LIST(),
 };
 
diff --git a/hw/apic_internal.h b/hw/apic_internal.h
index 0cab010..60a6a8b 100644
--- a/hw/apic_internal.h
+++ b/hw/apic_internal.h
@@ -61,6 +61,9 @@
 #define APIC_SV_DIRECTED_IO             (1<<12)
 #define APIC_SV_ENABLE                  (1<<8)
 
+#define VAPIC_ENABLE_BIT                0
+#define VAPIC_ENABLE_MASK               (1 << VAPIC_ENABLE_BIT)
+
 #define MAX_APICS 255
 
 #define MSI_SPACE_SIZE                  0x100000
@@ -82,7 +85,11 @@ typedef struct APICCommonClass
     void (*init)(APICCommonState *s);
     void (*set_base)(APICCommonState *s, uint64_t val);
     void (*set_tpr)(APICCommonState *s, uint8_t val);
+    uint8_t (*get_tpr)(APICCommonState *s);
+    void (*enable_tpr_reporting)(APICCommonState *s, bool enable);
+    void (*vapic_base_update)(APICCommonState *s);
     void (*external_nmi)(APICCommonState *s);
+    void (*pre_save)(APICCommonState *s);
     void (*post_load)(APICCommonState *s);
 } APICCommonClass;
 
@@ -114,9 +121,29 @@ struct APICCommonState {
     int64_t timer_expiry;
     int sipi_vector;
     int wait_for_sipi;
+
+    uint32_t vapic_control;
+    DeviceState *vapic;
+    target_phys_addr_t vapic_paddr; /* note: persistence via kvmvapic */
 };
 
+typedef struct VAPICState {
+    uint8_t tpr;
+    uint8_t isr;
+    uint8_t zero;
+    uint8_t irr;
+    uint8_t enabled;
+} QEMU_PACKED VAPICState;
+
+extern bool apic_report_tpr_access;
+
 void apic_report_irq_delivered(int delivered);
 bool apic_next_timer(APICCommonState *s, int64_t current_time);
+void apic_enable_tpr_access_reporting(DeviceState *d, bool enable);
+void apic_enable_vapic(DeviceState *d, target_phys_addr_t paddr);
+void apic_poll_irq(DeviceState *d);
+
+void vapic_report_tpr_access(DeviceState *dev, void *cpu, target_ulong ip,
+                             TPRAccess access);
 
 #endif /* !QEMU_APIC_INTERNAL_H */
diff --git a/hw/kvm/apic.c b/hw/kvm/apic.c
index 5bb0a4b..9ca68f8 100644
--- a/hw/kvm/apic.c
+++ b/hw/kvm/apic.c
@@ -92,6 +92,35 @@ static void kvm_apic_set_tpr(APICCommonState *s, uint8_t val)
     s->tpr = (val & 0x0f) << 4;
 }
 
+static uint8_t kvm_apic_get_tpr(APICCommonState *s)
+{
+    return s->tpr >> 4;
+}
+
+static void kvm_apic_enable_tpr_reporting(APICCommonState *s, bool enable)
+{
+    struct kvm_tpr_access_ctl ctl = {
+        .enabled = enable
+    };
+
+    kvm_vcpu_ioctl(s->cpu_env, KVM_TPR_ACCESS_REPORTING, &ctl);
+}
+
+static void kvm_apic_vapic_base_update(APICCommonState *s)
+{
+    struct kvm_vapic_addr vapid_addr = {
+        .vapic_addr = s->vapic_paddr,
+    };
+    int ret;
+
+    ret = kvm_vcpu_ioctl(s->cpu_env, KVM_SET_VAPIC_ADDR, &vapid_addr);
+    if (ret < 0) {
+        fprintf(stderr, "KVM: setting VAPIC address failed (%s)\n",
+                strerror(-ret));
+        abort();
+    }
+}
+
 static void do_inject_external_nmi(void *data)
 {
     APICCommonState *s = data;
@@ -129,6 +158,9 @@ static void kvm_apic_class_init(ObjectClass *klass, void *data)
     k->init = kvm_apic_init;
     k->set_base = kvm_apic_set_base;
     k->set_tpr = kvm_apic_set_tpr;
+    k->get_tpr = kvm_apic_get_tpr;
+    k->enable_tpr_reporting = kvm_apic_enable_tpr_reporting;
+    k->vapic_base_update = kvm_apic_vapic_base_update;
     k->external_nmi = kvm_apic_external_nmi;
 }
 
diff --git a/hw/kvmvapic.c b/hw/kvmvapic.c
new file mode 100644
index 0000000..36ccfbc
--- /dev/null
+++ b/hw/kvmvapic.c
@@ -0,0 +1,805 @@
+/*
+ * TPR optimization for 32-bit Windows guests (XP and Server 2003)
+ *
+ * Copyright (C) 2007-2008 Qumranet Technologies
+ * Copyright (C) 2012      Jan Kiszka, Siemens AG
+ *
+ * This work is licensed under the terms of the GNU GPL version 2, or
+ * (at your option) any later version. See the COPYING file in the
+ * top-level directory.
+ */
+#include "sysemu.h"
+#include "cpus.h"
+#include "kvm.h"
+#include "apic_internal.h"
+
+#define APIC_DEFAULT_ADDRESS    0xfee00000
+
+#define VAPIC_IO_PORT           0x7e
+
+#define VAPIC_CPU_SHIFT         7
+
+#define ROM_BLOCK_SIZE          512
+#define ROM_BLOCK_MASK          (~(ROM_BLOCK_SIZE - 1))
+
+typedef enum VAPICMode {
+    VAPIC_INACTIVE = 0,
+    VAPIC_ACTIVE   = 1,
+    VAPIC_STANDBY  = 2,
+} VAPICMode;
+
+typedef struct VAPICHandlers {
+    uint32_t set_tpr;
+    uint32_t set_tpr_eax;
+    uint32_t get_tpr[8];
+    uint32_t get_tpr_stack;
+} QEMU_PACKED VAPICHandlers;
+
+typedef struct GuestROMState {
+    char signature[8];
+    uint32_t vaddr;
+    uint32_t fixup_start;
+    uint32_t fixup_end;
+    uint32_t vapic_vaddr;
+    uint32_t vapic_size;
+    uint32_t vcpu_shift;
+    uint32_t real_tpr_addr;
+    VAPICHandlers up;
+    VAPICHandlers mp;
+} QEMU_PACKED GuestROMState;
+
+typedef struct VAPICROMState {
+    SysBusDevice busdev;
+    MemoryRegion io;
+    MemoryRegion rom;
+    uint32_t state;
+    uint32_t rom_state_paddr;
+    uint32_t rom_state_vaddr;
+    uint32_t vapic_paddr;
+    uint32_t real_tpr_addr;
+    GuestROMState rom_state;
+    size_t rom_size;
+    bool rom_mapped_writable;
+} VAPICROMState;
+
+#define TPR_INSTR_ABS_MODRM             0x1
+#define TPR_INSTR_MATCH_MODRM_REG       0x2
+
+typedef struct TPRInstruction {
+    uint8_t opcode;
+    uint8_t modrm_reg;
+    unsigned int flags;
+    TPRAccess access;
+    size_t length;
+    off_t addr_offset;
+} TPRInstruction;
+
+/* must be sorted by length, shortest first */
+static const TPRInstruction tpr_instr[] = {
+    { /* mov abs to eax */
+        .opcode = 0xa1,
+        .access = TPR_ACCESS_READ,
+        .length = 5,
+        .addr_offset = 1,
+    },
+    { /* mov eax to abs */
+        .opcode = 0xa3,
+        .access = TPR_ACCESS_WRITE,
+        .length = 5,
+        .addr_offset = 1,
+    },
+    { /* mov r32 to r/m32 */
+        .opcode = 0x89,
+        .flags = TPR_INSTR_ABS_MODRM,
+        .access = TPR_ACCESS_WRITE,
+        .length = 6,
+        .addr_offset = 2,
+    },
+    { /* mov r/m32 to r32 */
+        .opcode = 0x8b,
+        .flags = TPR_INSTR_ABS_MODRM,
+        .access = TPR_ACCESS_READ,
+        .length = 6,
+        .addr_offset = 2,
+    },
+    { /* push r/m32 */
+        .opcode = 0xff,
+        .modrm_reg = 6,
+        .flags = TPR_INSTR_ABS_MODRM | TPR_INSTR_MATCH_MODRM_REG,
+        .access = TPR_ACCESS_READ,
+        .length = 6,
+        .addr_offset = 2,
+    },
+    { /* mov imm32, r/m32 (c7/0) */
+        .opcode = 0xc7,
+        .modrm_reg = 0,
+        .flags = TPR_INSTR_ABS_MODRM | TPR_INSTR_MATCH_MODRM_REG,
+        .access = TPR_ACCESS_WRITE,
+        .length = 10,
+        .addr_offset = 2,
+    },
+};
+
+static void read_guest_rom_state(VAPICROMState *s)
+{
+    cpu_physical_memory_rw(s->rom_state_paddr, (void *)&s->rom_state,
+                           sizeof(GuestROMState), 0);
+}
+
+static void write_guest_rom_state(VAPICROMState *s)
+{
+    cpu_physical_memory_rw(s->rom_state_paddr, (void *)&s->rom_state,
+                           sizeof(GuestROMState), 1);
+}
+
+static void update_guest_rom_state(VAPICROMState *s)
+{
+    read_guest_rom_state(s);
+
+    s->rom_state.real_tpr_addr = cpu_to_le32(s->real_tpr_addr);
+    s->rom_state.vcpu_shift = cpu_to_le32(VAPIC_CPU_SHIFT);
+
+    write_guest_rom_state(s);
+}
+
+static int find_real_tpr_addr(VAPICROMState *s, CPUState *env)
+{
+    target_phys_addr_t paddr;
+    target_ulong addr;
+
+    if (s->state == VAPIC_ACTIVE) {
+        return 0;
+    }
+    /*
+     * If there is no prior TPR access instruction we could analyze (which is
+     * the case after resume from hibernation), we need to scan the possible
+     * virtual address space for the APIC mapping.
+     */
+    for (addr = 0xfffff000; addr >= 0x80000000; addr -= TARGET_PAGE_SIZE) {
+        paddr = cpu_get_phys_page_debug(env, addr);
+        if (paddr != APIC_DEFAULT_ADDRESS) {
+            continue;
+        }
+        s->real_tpr_addr = addr + 0x80;
+        update_guest_rom_state(s);
+        return 0;
+    }
+    return -1;
+}
+
+static uint8_t modrm_reg(uint8_t modrm)
+{
+    return (modrm >> 3) & 7;
+}
+
+static bool is_abs_modrm(uint8_t modrm)
+{
+    return (modrm & 0xc7) == 0x05;
+}
+
+static bool opcode_matches(uint8_t *opcode, const TPRInstruction *instr)
+{
+    return opcode[0] == instr->opcode &&
+        (!(instr->flags & TPR_INSTR_ABS_MODRM) || is_abs_modrm(opcode[1])) &&
+        (!(instr->flags & TPR_INSTR_MATCH_MODRM_REG) ||
+         modrm_reg(opcode[1]) == instr->modrm_reg);
+}
+
+static int evaluate_tpr_instruction(VAPICROMState *s, CPUState *env,
+                                    target_ulong *pip, TPRAccess access)
+{
+    const TPRInstruction *instr;
+    target_ulong ip = *pip;
+    uint8_t opcode[2];
+    uint32_t real_tpr_addr;
+    int i;
+
+    if ((ip & 0xf0000000ULL) != 0x80000000ULL &&
+        (ip & 0xf0000000ULL) != 0xe0000000ULL) {
+        return -1;
+    }
+
+    /*
+     * Early Windows 2003 SMP initialization contains a
+     *
+     *   mov imm32, r/m32
+     *
+     * instruction that is patched by TPR optimization. The problem is that
+     * RSP, used by the patched instruction, is zero, so the guest gets a
+     * double fault and dies.
+     */
+    if (env->regs[R_ESP] == 0) {
+        return -1;
+    }
+
+    if (kvm_enabled() && !kvm_irqchip_in_kernel()) {
+        /*
+         * KVM without kernel-based TPR access reporting will pass an IP that
+         * points after the accessing instruction. So we need to look backward
+         * to find the reason.
+         */
+        for (i = 0; i < ARRAY_SIZE(tpr_instr); i++) {
+            instr = &tpr_instr[i];
+            if (instr->access != access) {
+                continue;
+            }
+            if (cpu_memory_rw_debug(env, ip - instr->length, opcode,
+                                    sizeof(opcode), 0) < 0) {
+                return -1;
+            }
+            if (opcode_matches(opcode, instr)) {
+                ip -= instr->length;
+                goto instruction_ok;
+            }
+        }
+        return -1;
+    } else {
+        if (cpu_memory_rw_debug(env, ip, opcode, sizeof(opcode), 0) < 0) {
+            return -1;
+        }
+        for (i = 0; i < ARRAY_SIZE(tpr_instr); i++) {
+            instr = &tpr_instr[i];
+            if (opcode_matches(opcode, instr)) {
+                goto instruction_ok;
+            }
+        }
+        return -1;
+    }
+
+instruction_ok:
+    /*
+     * Grab the virtual TPR address from the instruction
+     * and update the cached values.
+     */
+    if (cpu_memory_rw_debug(env, ip + instr->addr_offset,
+                            (void *)&real_tpr_addr,
+                            sizeof(real_tpr_addr), 0) < 0) {
+        return -1;
+    }
+    real_tpr_addr = le32_to_cpu(real_tpr_addr);
+    if ((real_tpr_addr & 0xfff) != 0x80) {
+        return -1;
+    }
+    s->real_tpr_addr = real_tpr_addr;
+    update_guest_rom_state(s);
+
+    *pip = ip;
+    return 0;
+}
+
+static int update_rom_mapping(VAPICROMState *s, CPUState *env, target_ulong ip)
+{
+    target_phys_addr_t paddr;
+    uint32_t rom_state_vaddr;
+    uint32_t pos, patch, offset;
+
+    /* nothing to do if already activated */
+    if (s->state == VAPIC_ACTIVE) {
+        return 0;
+    }
+
+    /* bail out if ROM init code was not executed (missing ROM?) */
+    if (s->state == VAPIC_INACTIVE) {
+        return -1;
+    }
+
+    /* find out virtual address of the ROM */
+    rom_state_vaddr = s->rom_state_paddr + (ip & 0xf0000000);
+    paddr = cpu_get_phys_page_debug(env, rom_state_vaddr);
+    if (paddr == -1) {
+        return -1;
+    }
+    paddr += rom_state_vaddr & ~TARGET_PAGE_MASK;
+    if (paddr != s->rom_state_paddr) {
+        return -1;
+    }
+    read_guest_rom_state(s);
+    if (memcmp(s->rom_state.signature, "kvm aPiC", 8) != 0) {
+        return -1;
+    }
+    s->rom_state_vaddr = rom_state_vaddr;
+
+    /* fixup addresses in ROM if needed */
+    if (rom_state_vaddr == le32_to_cpu(s->rom_state.vaddr)) {
+        return 0;
+    }
+    for (pos = le32_to_cpu(s->rom_state.fixup_start);
+         pos < le32_to_cpu(s->rom_state.fixup_end);
+         pos += 4) {
+        cpu_physical_memory_rw(paddr + pos - s->rom_state.vaddr,
+                               (void *)&offset, sizeof(offset), 0);
+        offset = le32_to_cpu(offset);
+        cpu_physical_memory_rw(paddr + offset, (void *)&patch,
+                               sizeof(patch), 0);
+        patch = le32_to_cpu(patch);
+        patch += rom_state_vaddr - le32_to_cpu(s->rom_state.vaddr);
+        patch = cpu_to_le32(patch);
+        cpu_physical_memory_rw(paddr + offset, (void *)&patch,
+                               sizeof(patch), 1);
+    }
+    read_guest_rom_state(s);
+    s->vapic_paddr = paddr + le32_to_cpu(s->rom_state.vapic_vaddr) -
+        le32_to_cpu(s->rom_state.vaddr);
+
+    return 0;
+}
+
+/*
+ * Tries to read the unique processor number from the Kernel Processor Control
+ * Region (KPCR) of 32-bit Windows XP and Server 2003. Returns -1 if the KPCR
+ * cannot be accessed or is considered invalid. This also ensures that we are
+ * not patching the wrong guest.
+ */
+static int get_kpcr_number(CPUState *env)
+{
+    struct kpcr {
+        uint8_t  fill1[0x1c];
+        uint32_t self;
+        uint8_t  fill2[0x31];
+        uint8_t  number;
+    } QEMU_PACKED kpcr;
+
+    if (cpu_memory_rw_debug(env, env->segs[R_FS].base,
+                            (void *)&kpcr, sizeof(kpcr), 0) < 0 ||
+        kpcr.self != env->segs[R_FS].base) {
+        return -1;
+    }
+    return kpcr.number;
+}
+
+static int vapic_enable(VAPICROMState *s, CPUState *env)
+{
+    int cpu_number = get_kpcr_number(env);
+    target_phys_addr_t vapic_paddr;
+    static const uint8_t enabled = 1;
+
+    if (cpu_number < 0) {
+        return -1;
+    }
+    vapic_paddr = s->vapic_paddr +
+        (((target_phys_addr_t)cpu_number) << VAPIC_CPU_SHIFT);
+    cpu_physical_memory_rw(vapic_paddr + offsetof(VAPICState, enabled),
+                           (void *)&enabled, sizeof(enabled), 1);
+    apic_enable_vapic(env->apic_state, vapic_paddr);
+
+    s->state = VAPIC_ACTIVE;
+
+    return 0;
+}
+
+static void patch_byte(CPUState *env, target_ulong addr, uint8_t byte)
+{
+    cpu_memory_rw_debug(env, addr, &byte, 1, 1);
+}
+
+static void patch_call(VAPICROMState *s, CPUState *env, target_ulong ip,
+                       uint32_t target)
+{
+    uint32_t offset;
+
+    offset = cpu_to_le32(target - ip - 5);
+    patch_byte(env, ip, 0xe8); /* call near */
+    cpu_memory_rw_debug(env, ip + 1, (void *)&offset, sizeof(offset), 1);
+}
+
+static void patch_instruction(VAPICROMState *s, CPUState *env, target_ulong ip)
+{
+    target_phys_addr_t paddr;
+    VAPICHandlers *handlers;
+    uint8_t opcode[2];
+    uint32_t imm32;
+
+    if (smp_cpus == 1) {
+        handlers = &s->rom_state.up;
+    } else {
+        handlers = &s->rom_state.mp;
+    }
+
+    pause_all_vcpus();
+
+    cpu_memory_rw_debug(env, ip, opcode, sizeof(opcode), 0);
+
+    switch (opcode[0]) {
+    case 0x89: /* mov r32 to r/m32 */
+        patch_byte(env, ip, 0x50 + modrm_reg(opcode[1]));  /* push reg */
+        patch_call(s, env, ip + 1, handlers->set_tpr);
+        break;
+    case 0x8b: /* mov r/m32 to r32 */
+        patch_byte(env, ip, 0x90);
+        patch_call(s, env, ip + 1, handlers->get_tpr[modrm_reg(opcode[1])]);
+        break;
+    case 0xa1: /* mov abs to eax */
+        patch_call(s, env, ip, handlers->get_tpr[0]);
+        break;
+    case 0xa3: /* mov eax to abs */
+        patch_call(s, env, ip, handlers->set_tpr_eax);
+        break;
+    case 0xc7: /* mov imm32, r/m32 (c7/0) */
+        patch_byte(env, ip, 0x68);  /* push imm32 */
+        cpu_memory_rw_debug(env, ip + 6, (void *)&imm32, sizeof(imm32), 0);
+        cpu_memory_rw_debug(env, ip + 1, (void *)&imm32, sizeof(imm32), 1);
+        patch_call(s, env, ip + 5, handlers->set_tpr);
+        break;
+    case 0xff: /* push r/m32 */
+        patch_byte(env, ip, 0x50); /* push eax */
+        patch_call(s, env, ip + 1, handlers->get_tpr_stack);
+        break;
+    default:
+        abort();
+    }
+
+    resume_all_vcpus();
+
+    paddr = cpu_get_phys_page_debug(env, ip);
+    paddr += ip & ~TARGET_PAGE_MASK;
+    tb_invalidate_phys_page_range(paddr, paddr + 1, 1);
+}
+
+void vapic_report_tpr_access(DeviceState *dev, void *cpu, target_ulong ip,
+                             TPRAccess access)
+{
+    VAPICROMState *s = DO_UPCAST(VAPICROMState, busdev.qdev, dev);
+    CPUState *env = cpu;
+
+    cpu_synchronize_state(env);
+
+    if (evaluate_tpr_instruction(s, env, &ip, access) < 0) {
+        if (s->state == VAPIC_ACTIVE) {
+            vapic_enable(s, env);
+        }
+        return;
+    }
+    if (update_rom_mapping(s, env, ip) < 0) {
+        return;
+    }
+    if (vapic_enable(s, env) < 0) {
+        return;
+    }
+    patch_instruction(s, env, ip);
+}
+
+typedef struct VAPICEnableTPRReporting {
+    DeviceState *apic;
+    bool enable;
+} VAPICEnableTPRReporting;
+
+static void vapic_do_enable_tpr_reporting(void *data)
+{
+    VAPICEnableTPRReporting *info = data;
+
+    apic_enable_tpr_access_reporting(info->apic, info->enable);
+}
+
+static void vapic_enable_tpr_reporting(bool enable)
+{
+    VAPICEnableTPRReporting info = {
+        .enable = enable,
+    };
+    CPUState *env;
+
+    for (env = first_cpu; env != NULL; env = env->next_cpu) {
+        info.apic = env->apic_state;
+        run_on_cpu(env, vapic_do_enable_tpr_reporting, &info);
+    }
+}
+
+static void vapic_reset(DeviceState *dev)
+{
+    VAPICROMState *s = DO_UPCAST(VAPICROMState, busdev.qdev, dev);
+
+    if (s->state == VAPIC_ACTIVE) {
+        s->state = VAPIC_STANDBY;
+    }
+    vapic_enable_tpr_reporting(false);
+}
+
+/*
+ * Set the IRQ polling hypercalls to the supported variant:
+ *  - vmcall if using KVM in-kernel irqchip
+ *  - 32-bit VAPIC port write otherwise
+ */
+static int patch_hypercalls(VAPICROMState *s)
+{
+    target_phys_addr_t rom_paddr = s->rom_state_paddr & ROM_BLOCK_MASK;
+    static const uint8_t vmcall_pattern[] = { /* vmcall */
+        0xb8, 0x1, 0, 0, 0, 0xf, 0x1, 0xc1
+    };
+    static const uint8_t outl_pattern[] = { /* nop; outl %eax,0x7e */
+        0xb8, 0x1, 0, 0, 0, 0x90, 0xe7, 0x7e
+    };
+    uint8_t alternates[2];
+    const uint8_t *pattern;
+    const uint8_t *patch;
+    int patches = 0;
+    off_t pos;
+    uint8_t *rom;
+
+    rom = g_malloc(s->rom_size);
+    cpu_physical_memory_rw(rom_paddr, rom, s->rom_size, 0);
+
+    for (pos = 0; pos < s->rom_size - sizeof(vmcall_pattern); pos++) {
+        if (kvm_irqchip_in_kernel()) {
+            pattern = outl_pattern;
+            alternates[0] = outl_pattern[7];
+            alternates[1] = outl_pattern[7];
+            patch = &vmcall_pattern[5];
+        } else {
+            pattern = vmcall_pattern;
+            alternates[0] = vmcall_pattern[7];
+            alternates[1] = 0xd9; /* AMD's VMMCALL */
+            patch = &outl_pattern[5];
+        }
+        if (memcmp(rom + pos, pattern, 7) == 0 &&
+            (rom[pos + 7] == alternates[0] || rom[pos + 7] == alternates[1])) {
+            cpu_physical_memory_rw(rom_paddr + pos + 5, (uint8_t *)patch,
+                                   3, 1);
+            /*
+             * Don't flush the tb here. Under ordinary conditions, the patched
+             * calls are miles away from the current IP. Under malicious
+             * conditions, the guest could trick us to crash.
+             */
+        }
+    }
+
+    g_free(rom);
+
+    if (patches != 0 && patches != 2) {
+        return -1;
+    }
+
+    return 0;
+}
+
+/*
+ * For TCG mode or the time KVM honors read-only memory regions, we need to
+ * enable write access to the option ROM so that variables can be updated by
+ * the guest.
+ */
+static void vapic_map_rom_writable(VAPICROMState *s)
+{
+    target_phys_addr_t rom_paddr = s->rom_state_paddr & ROM_BLOCK_MASK;
+    MemoryRegionSection section;
+    MemoryRegion *as;
+    size_t rom_size;
+    uint8_t *ram;
+
+    as = sysbus_address_space(&s->busdev);
+
+    if (s->rom_mapped_writable) {
+        memory_region_del_subregion(as, &s->rom);
+        memory_region_destroy(&s->rom);
+    }
+
+    /* grab RAM memory region (region @rom_paddr may still be pc.rom) */
+    section = memory_region_find(as, 0, 1);
+
+    /* read ROM size from RAM region */
+    ram = memory_region_get_ram_ptr(section.mr);
+    rom_size = ram[rom_paddr + 2] * ROM_BLOCK_SIZE;
+    s->rom_size = rom_size;
+
+    /* We need to round up to avoid creating subpages
+     * from which we cannot run code. */
+    rom_size = TARGET_PAGE_ALIGN(rom_size);
+
+    memory_region_init_alias(&s->rom, "kvmvapic-rom", section.mr, rom_paddr,
+                             rom_size);
+    memory_region_add_subregion_overlap(as, rom_paddr, &s->rom, 1000);
+    s->rom_mapped_writable = true;
+}
+
+static int vapic_prepare(VAPICROMState *s)
+{
+    vapic_map_rom_writable(s);
+
+    if (patch_hypercalls(s) < 0) {
+        return -1;
+    }
+
+    vapic_enable_tpr_reporting(true);
+
+    return 0;
+}
+
+static void vapic_write(void *opaque, target_phys_addr_t addr, uint64_t data,
+                        unsigned int size)
+{
+    CPUState *env = cpu_single_env;
+    target_phys_addr_t rom_paddr;
+    VAPICROMState *s = opaque;
+
+    cpu_synchronize_state(env);
+
+    /*
+     * The VAPIC supports two PIO-based hypercalls, both via port 0x7E.
+     *  o 16-bit write access:
+     *    Reports the option ROM initialization to the hypervisor. Written
+     *    value is the offset of the state structure in the ROM.
+     *  o 8-bit write access:
+     *    Reactivates the VAPIC after a guest hibernation, i.e. after the
+     *    option ROM content has been re-initialized by a guest power cycle.
+     *  o 32-bit write access:
+     *    Poll for pending IRQs, considering the current VAPIC state.
+     */
+    switch (size) {
+    case 2:
+        if (s->state == VAPIC_INACTIVE) {
+            rom_paddr = (env->segs[R_CS].base + env->eip) & ROM_BLOCK_MASK;
+            s->rom_state_paddr = rom_paddr + data;
+
+            s->state = VAPIC_STANDBY;
+        }
+        if (vapic_prepare(s) < 0) {
+            s->state = VAPIC_INACTIVE;
+            break;
+        }
+        break;
+    case 1:
+        if (kvm_enabled()) {
+            /*
+             * Disable triggering instruction in ROM by writing a NOP.
+             *
+             * We cannot do this in TCG mode as the reported IP is not
+             * accurate.
+             */
+            pause_all_vcpus();
+            patch_byte(env, env->eip - 2, 0x66);
+            patch_byte(env, env->eip - 1, 0x90);
+            resume_all_vcpus();
+        }
+
+        if (s->state == VAPIC_ACTIVE) {
+            break;
+        }
+        if (update_rom_mapping(s, env, env->eip) < 0) {
+            break;
+        }
+        if (find_real_tpr_addr(s, env) < 0) {
+            break;
+        }
+        vapic_enable(s, env);
+        break;
+    default:
+    case 4:
+        if (!kvm_irqchip_in_kernel()) {
+            apic_poll_irq(env->apic_state);
+        }
+        break;
+    }
+}
+
+static const MemoryRegionOps vapic_ops = {
+    .write = vapic_write,
+    .endianness = DEVICE_NATIVE_ENDIAN,
+};
+
+static int vapic_init(SysBusDevice *dev)
+{
+    VAPICROMState *s = FROM_SYSBUS(VAPICROMState, dev);
+
+    memory_region_init_io(&s->io, &vapic_ops, s, "kvmvapic", 2);
+    sysbus_add_io(dev, VAPIC_IO_PORT, &s->io);
+    sysbus_init_ioports(dev, VAPIC_IO_PORT, 2);
+
+    option_rom[nb_option_roms].name = "kvmvapic.bin";
+    option_rom[nb_option_roms].bootindex = -1;
+    nb_option_roms++;
+
+    return 0;
+}
+
+static void do_vapic_enable(void *data)
+{
+    VAPICROMState *s = data;
+
+    vapic_enable(s, first_cpu);
+}
+
+static int vapic_post_load(void *opaque, int version_id)
+{
+    VAPICROMState *s = opaque;
+    uint8_t *zero;
+
+    /*
+     * The old implementation of qemu-kvm did not provide the state
+     * VAPIC_STANDBY. Reconstruct it.
+     */
+    if (s->state == VAPIC_INACTIVE && s->rom_state_paddr != 0) {
+        s->state = VAPIC_STANDBY;
+    }
+
+    if (s->state != VAPIC_INACTIVE) {
+        if (vapic_prepare(s) < 0) {
+            return -1;
+        }
+    }
+    if (s->state == VAPIC_ACTIVE) {
+        if (smp_cpus == 1) {
+            run_on_cpu(first_cpu, do_vapic_enable, s);
+        } else {
+            zero = g_malloc0(s->rom_state.vapic_size);
+            cpu_physical_memory_rw(s->vapic_paddr, zero,
+                                   s->rom_state.vapic_size, 1);
+            g_free(zero);
+        }
+    }
+
+    return 0;
+}
+
+static const VMStateDescription vmstate_handlers = {
+    .name = "kvmvapic-handlers",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .minimum_version_id_old = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT32(set_tpr, VAPICHandlers),
+        VMSTATE_UINT32(set_tpr_eax, VAPICHandlers),
+        VMSTATE_UINT32_ARRAY(get_tpr, VAPICHandlers, 8),
+        VMSTATE_UINT32(get_tpr_stack, VAPICHandlers),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static const VMStateDescription vmstate_guest_rom = {
+    .name = "kvmvapic-guest-rom",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .minimum_version_id_old = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_UNUSED(8),     /* signature */
+        VMSTATE_UINT32(vaddr, GuestROMState),
+        VMSTATE_UINT32(fixup_start, GuestROMState),
+        VMSTATE_UINT32(fixup_end, GuestROMState),
+        VMSTATE_UINT32(vapic_vaddr, GuestROMState),
+        VMSTATE_UINT32(vapic_size, GuestROMState),
+        VMSTATE_UINT32(vcpu_shift, GuestROMState),
+        VMSTATE_UINT32(real_tpr_addr, GuestROMState),
+        VMSTATE_STRUCT(up, GuestROMState, 0, vmstate_handlers, VAPICHandlers),
+        VMSTATE_STRUCT(mp, GuestROMState, 0, vmstate_handlers, VAPICHandlers),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static const VMStateDescription vmstate_vapic = {
+    .name = "kvm-tpr-opt",      /* compatible with qemu-kvm VAPIC */
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .minimum_version_id_old = 1,
+    .post_load = vapic_post_load,
+    .fields = (VMStateField[]) {
+        VMSTATE_STRUCT(rom_state, VAPICROMState, 0, vmstate_guest_rom,
+                       GuestROMState),
+        VMSTATE_UINT32(state, VAPICROMState),
+        VMSTATE_UINT32(real_tpr_addr, VAPICROMState),
+        VMSTATE_UINT32(rom_state_vaddr, VAPICROMState),
+        VMSTATE_UINT32(vapic_paddr, VAPICROMState),
+        VMSTATE_UINT32(rom_state_paddr, VAPICROMState),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static void vapic_class_init(ObjectClass *klass, void *data)
+{
+    SysBusDeviceClass *sc = SYS_BUS_DEVICE_CLASS(klass);
+    DeviceClass *dc = DEVICE_CLASS(klass);
+
+    dc->no_user = 1;
+    dc->reset   = vapic_reset;
+    dc->vmsd    = &vmstate_vapic;
+    sc->init    = vapic_init;
+}
+
+static TypeInfo vapic_type = {
+    .name          = "kvmvapic",
+    .parent        = TYPE_SYS_BUS_DEVICE,
+    .instance_size = sizeof(VAPICROMState),
+    .class_init    = vapic_class_init,
+};
+
+static void vapic_register(void)
+{
+    type_register_static(&vapic_type);
+}
+
+type_init(vapic_register);
