Re: [Qemu-devel] [PATCH 1/2] i386: Add a Virtual Machine Generation ID device

["Michael S. Tsirkin" <mst@redhat.com>]

On Mon, Oct 20, 2014 at 08:57:05AM +0300, Gal Hammer wrote:
> On 19/10/2014 18:14, Michael S. Tsirkin wrote:
> >On Sun, Oct 19, 2014 at 04:43:07PM +0300, Gal Hammer wrote:
> >>Based on Microsoft's sepecifications (paper can be dowloaded from
> >>http://go.microsoft.com/fwlink/?LinkId=260709), add a device
> >>description to the SSDT ACPI table and its implementation.
> >>
> >>The GUID is set using a global "vmgenid.uuid" parameter.
> >>
> >>Signed-off-by: Gal Hammer <ghammer@redhat.com>
> >>
> >>---
> >>  default-configs/i386-softmmu.mak     |   1 +
> >>  default-configs/x86_64-softmmu.mak   |   1 +
> >>  hw/acpi/core.c                       |   8 +++
> >>  hw/acpi/ich9.c                       |   8 +++
> >>  hw/acpi/piix4.c                      |   8 +++
> >>  hw/i386/acpi-build.c                 |   8 +++
> >>  hw/i386/acpi-dsdt.dsl                |   4 +-
> >>  hw/i386/acpi-dsdt.hex.generated      |   6 +-
> >>  hw/i386/pc.c                         |   8 +++
> >>  hw/i386/q35-acpi-dsdt.dsl            |   5 +-
> >>  hw/i386/q35-acpi-dsdt.hex.generated  |   8 +--
> >>  hw/i386/ssdt-misc.dsl                |  36 +++++++++++
> >>  hw/i386/ssdt-misc.hex.generated      |   8 +--
> >>  hw/isa/lpc_ich9.c                    |   1 +
> >>  hw/misc/Makefile.objs                |   1 +
> >>  hw/misc/vmgenid.c                    | 116 +++++++++++++++++++++++++++++++++++
> >>  include/hw/acpi/acpi.h               |   2 +
> >>  include/hw/acpi/acpi_dev_interface.h |   4 ++
> >>  include/hw/acpi/ich9.h               |   2 +
> >>  include/hw/i386/pc.h                 |   3 +
> >>  include/hw/misc/vmgenid.h            |  21 +++++++
> >>  21 files changed, 246 insertions(+), 13 deletions(-)
> >>  create mode 100644 hw/misc/vmgenid.c
> >>  create mode 100644 include/hw/misc/vmgenid.h
> >
> >Please document the host/guest API.
> >It seems that you are using a hard-coded hardware address,
> >and using up a GPE.
> 
> I'll add a document file which describes the device's implementation.
> 
> >
> >
> >>
> >>diff --git a/default-configs/i386-softmmu.mak b/default-configs/i386-softmmu.mak
> >>index 8e08841..bd33c75 100644
> >>--- a/default-configs/i386-softmmu.mak
> >>+++ b/default-configs/i386-softmmu.mak
> >>@@ -45,3 +45,4 @@ CONFIG_IOAPIC=y
> >>  CONFIG_ICC_BUS=y
> >>  CONFIG_PVPANIC=y
> >>  CONFIG_MEM_HOTPLUG=y
> >>+CONFIG_VMGENID=y
> >>diff --git a/default-configs/x86_64-softmmu.mak b/default-configs/x86_64-softmmu.mak
> >>index 66557ac..006fc7c 100644
> >>--- a/default-configs/x86_64-softmmu.mak
> >>+++ b/default-configs/x86_64-softmmu.mak
> >>@@ -45,3 +45,4 @@ CONFIG_IOAPIC=y
> >>  CONFIG_ICC_BUS=y
> >>  CONFIG_PVPANIC=y
> >>  CONFIG_MEM_HOTPLUG=y
> >>+CONFIG_VMGENID=y
> >>diff --git a/hw/acpi/core.c b/hw/acpi/core.c
> >>index a7368fb..a01c980 100644
> >>--- a/hw/acpi/core.c
> >>+++ b/hw/acpi/core.c
> >>@@ -28,6 +28,8 @@
> >>  #include "qapi-visit.h"
> >>  #include "qapi-event.h"
> >>
> >>+#define ACPI_VM_GENERATION_ID_CHANGED_STATUS 1
> >>+
> >>  struct acpi_table_header {
> >>      uint16_t _length;         /* our length, not actual part of the hdr */
> >>                                /* allows easier parsing for fw_cfg clients */
> >>@@ -680,3 +682,9 @@ void acpi_update_sci(ACPIREGS *regs, qemu_irq irq)
> >>                         (regs->pm1.evt.en & ACPI_BITMASK_TIMER_ENABLE) &&
> >>                         !(pm1a_sts & ACPI_BITMASK_TIMER_STATUS));
> >>  }
> >>+
> >>+void acpi_vm_generation_id_changed(ACPIREGS *acpi_regs, qemu_irq irq)
> >>+{
> >>+    acpi_regs->gpe.sts[0] |= ACPI_VM_GENERATION_ID_CHANGED_STATUS;
> >>+    acpi_update_sci(acpi_regs, irq);
> >>+}
> >>diff --git a/hw/acpi/ich9.c b/hw/acpi/ich9.c
> >>index 7b14bbb..5501c0e 100644
> >>--- a/hw/acpi/ich9.c
> >>+++ b/hw/acpi/ich9.c
> >>@@ -316,3 +316,11 @@ void ich9_pm_ospm_status(AcpiDeviceIf *adev, ACPIOSTInfoList ***list)
> >>
> >>      acpi_memory_ospm_status(&s->pm.acpi_memory_hotplug, list);
> >>  }
> >>+
> >>+void ich9_vm_generation_id_changed(AcpiDeviceIf *adev)
> >>+{
> >>+    ICH9LPCState *s = ICH9_LPC_DEVICE(adev);
> >>+    ICH9LPCPMRegs *pm = &s->pm;
> >>+
> >>+    acpi_vm_generation_id_changed(&pm->acpi_regs, pm->irq);
> >>+}
> >>diff --git a/hw/acpi/piix4.c b/hw/acpi/piix4.c
> >>index 0bfa814..ad0ef68 100644
> >>--- a/hw/acpi/piix4.c
> >>+++ b/hw/acpi/piix4.c
> >>@@ -580,6 +580,13 @@ static void piix4_ospm_status(AcpiDeviceIf *adev, ACPIOSTInfoList ***list)
> >>      acpi_memory_ospm_status(&s->acpi_memory_hotplug, list);
> >>  }
> >>
> >>+static void piix4_vm_generation_id_changed(AcpiDeviceIf *adev)
> >>+{
> >>+    PIIX4PMState *s = PIIX4_PM(adev);
> >>+
> >>+    acpi_vm_generation_id_changed(&s->ar, s->irq);
> >>+}
> >>+
> >>  static Property piix4_pm_properties[] = {
> >>      DEFINE_PROP_UINT32("smb_io_base", PIIX4PMState, smb_io_base, 0),
> >>      DEFINE_PROP_UINT8(ACPI_PM_PROP_S3_DISABLED, PIIX4PMState, disable_s3, 0),
> >>@@ -617,6 +624,7 @@ static void piix4_pm_class_init(ObjectClass *klass, void *data)
> >>      hc->plug = piix4_device_plug_cb;
> >>      hc->unplug_request = piix4_device_unplug_request_cb;
> >>      adevc->ospm_status = piix4_ospm_status;
> >>+    adevc->vm_generation_id_changed = piix4_vm_generation_id_changed;
> >>  }
> >>
> >>  static const TypeInfo piix4_pm_info = {
> >>diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> >>index 00be4bb..27d0494 100644
> >>--- a/hw/i386/acpi-build.c
> >>+++ b/hw/i386/acpi-build.c
> >>@@ -42,6 +42,7 @@
> >>  #include "hw/acpi/memory_hotplug.h"
> >>  #include "sysemu/tpm.h"
> >>  #include "hw/acpi/tpm.h"
> >>+#include "hw/misc/vmgenid.h"
> >>
> >>  /* Supported chipsets: */
> >>  #include "hw/acpi/piix4.h"
> >>@@ -96,6 +97,7 @@ typedef struct AcpiMiscInfo {
> >>      const unsigned char *dsdt_code;
> >>      unsigned dsdt_size;
> >>      uint16_t pvpanic_port;
> >>+    bool vm_generation_id_set;
> >>  } AcpiMiscInfo;
> >>
> >>  typedef struct AcpiBuildPciBusHotplugState {
> >>@@ -216,6 +218,7 @@ static void acpi_get_misc_info(AcpiMiscInfo *info)
> >>      info->has_hpet = hpet_find();
> >>      info->has_tpm = tpm_find();
> >>      info->pvpanic_port = pvpanic_port();
> >>+    info->vm_generation_id_set = vm_generation_id_set();
> >>  }
> >>
> >>  static void acpi_get_pci_info(PcPciInfo *info)
> >>@@ -1088,6 +1091,11 @@ build_ssdt(GArray *table_data, GArray *linker,
> >>      ACPI_BUILD_SET_LE(ssdt_ptr, sizeof(ssdp_misc_aml),
> >>                        ssdt_isa_pest[0], 16, misc->pvpanic_port);
> >>
> >>+    if (!misc->vm_generation_id_set) {
> >>+        ACPI_BUILD_SET_LE(ssdt_ptr, sizeof(ssdp_misc_aml),
> >>+                          ssdt_acpi_vm_gid_addr[0], 32, 0);
> >>+    }
> >>+
> >>      ACPI_BUILD_SET_LE(ssdt_ptr, sizeof(ssdp_misc_aml),
> >>                        ssdt_mctrl_nr_slots[0], 32, nr_mem);
> >>
> >>diff --git a/hw/i386/acpi-dsdt.dsl b/hw/i386/acpi-dsdt.dsl
> >>index 559f4b6..10b4afb 100644
> >>--- a/hw/i386/acpi-dsdt.dsl
> >>+++ b/hw/i386/acpi-dsdt.dsl
> >>@@ -307,7 +307,9 @@ DefinitionBlock (
> >>      Scope(\_GPE) {
> >>          Name(_HID, "ACPI0006")
> >>
> >>-        Method(_L00) {
> >>+        External(\_SB.VMGI, DeviceObj)
> >>+        Method(_E00) {
> >>+            Notify(\_SB.VMGI, 0x80)
> >>          }
> >>          Method(_E01) {
> >>              // PCI hotplug event
> >>diff --git a/hw/i386/acpi-dsdt.hex.generated b/hw/i386/acpi-dsdt.hex.generated
> >>index a21bf41..3fd06d2 100644
> >>--- a/hw/i386/acpi-dsdt.hex.generated
> >>+++ b/hw/i386/acpi-dsdt.hex.generated
> >>@@ -8,7 +8,7 @@ static unsigned char AcpiDsdtAmlCode[] = {
> >>  0x0,
> >>  0x0,
> >>  0x1,
> >>-0x1f,
> >>+0x18,
> >>  0x42,
> >>  0x58,
> >>  0x50,
> >>@@ -32,8 +32,8 @@ static unsigned char AcpiDsdtAmlCode[] = {
> >>  0x54,
> >>  0x4c,
> >>  0x28,
> >>-0x5,
> >>-0x10,
> >>+0x8,
> >>+0x14,
> >>  0x20,
> >>  0x10,
> >>  0x49,
> >>diff --git a/hw/i386/pc.c b/hw/i386/pc.c
> >>index d045e8b..95ec233 100644
> >>--- a/hw/i386/pc.c
> >>+++ b/hw/i386/pc.c
> >>@@ -59,6 +59,7 @@
> >>  #include "hw/pci/pci_host.h"
> >>  #include "acpi-build.h"
> >>  #include "hw/mem/pc-dimm.h"
> >>+#include "hw/misc/vmgenid.h"
> >>  #include "trace.h"
> >>  #include "qapi/visitor.h"
> >>
> >>@@ -1361,6 +1362,7 @@ void pc_basic_device_init(ISABus *isa_bus, qemu_irq *gsi,
> >>      int i;
> >>      DriveInfo *fd[MAX_FD];
> >>      DeviceState *hpet = NULL;
> >>+    DeviceState *vmgenid;
> >>      int pit_isa_irq = 0;
> >>      qemu_irq pit_alt_irq = NULL;
> >>      qemu_irq rtc_irq = NULL;
> >>@@ -1459,6 +1461,12 @@ void pc_basic_device_init(ISABus *isa_bus, qemu_irq *gsi,
> >>          fd[i] = drive_get(IF_FLOPPY, 0, i);
> >>      }
> >>      *floppy = fdctrl_init_isa(isa_bus, fd);
> >>+
> >>+    vmgenid = qdev_try_create(NULL, VMGENID_DEVICE);
> >>+    if (vmgenid) {
> >>+        qdev_init_nofail(vmgenid);
> >>+        sysbus_mmio_map(SYS_BUS_DEVICE(vmgenid), 0, VMGENID_BASE_ADDRESS);
> >>+    }
> >>  }
> >>
> >>  void pc_nic_init(ISABus *isa_bus, PCIBus *pci_bus)
> >>diff --git a/hw/i386/q35-acpi-dsdt.dsl b/hw/i386/q35-acpi-dsdt.dsl
> >>index 054b035..b1d04e2 100644
> >>--- a/hw/i386/q35-acpi-dsdt.dsl
> >>+++ b/hw/i386/q35-acpi-dsdt.dsl
> >>@@ -415,7 +415,10 @@ DefinitionBlock (
> >>      Scope(\_GPE) {
> >>          Name(_HID, "ACPI0006")
> >>
> >>-        Method(_L00) {
> >>+        External(\_SB.VMGI, DeviceObj)
> >>+        Method(_E00)
> >>+        {
> >>+            Notify(\_SB.VMGI, 0x80)
> >>          }
> >>          Method(_L01) {
> >>          }
> >>diff --git a/hw/i386/q35-acpi-dsdt.hex.generated b/hw/i386/q35-acpi-dsdt.hex.generated
> >>index c9eb4ac..866e648 100644
> >>--- a/hw/i386/q35-acpi-dsdt.hex.generated
> >>+++ b/hw/i386/q35-acpi-dsdt.hex.generated
> >>@@ -8,7 +8,7 @@ static unsigned char Q35AcpiDsdtAmlCode[] = {
> >>  0x0,
> >>  0x0,
> >>  0x1,
> >>-0xb7,
> >>+0xac,
> >>  0x42,
> >>  0x58,
> >>  0x50,
> >>@@ -31,9 +31,9 @@ static unsigned char Q35AcpiDsdtAmlCode[] = {
> >>  0x4e,
> >>  0x54,
> >>  0x4c,
> >>-0x15,
> >>-0x11,
> >>-0x13,
> >>+0x28,
> >>+0x8,
> >>+0x14,
> >>  0x20,
> >>  0x10,
> >>  0x49,
> >>diff --git a/hw/i386/ssdt-misc.dsl b/hw/i386/ssdt-misc.dsl
> >>index 0fd4480..6ae09fb 100644
> >>--- a/hw/i386/ssdt-misc.dsl
> >>+++ b/hw/i386/ssdt-misc.dsl
> >>@@ -13,6 +13,7 @@
> >>   * with this program; if not, see <http://www.gnu.org/licenses/>.
> >>   */
> >>  #include "hw/acpi/pc-hotplug.h"
> >>+#include "hw/misc/vmgenid.h"
> >>
> >>  ACPI_EXTRACT_ALL_CODE ssdp_misc_aml
> >>
> >>@@ -118,6 +119,41 @@ DefinitionBlock ("ssdt-misc.aml", "SSDT", 0x01, "BXPC", "BXSSDTSUSP", 0x1)
> >>          }
> >>      }
> >>
> >>+    Scope(\_SB) {
> >>+        Device(VMGI) {
> >>+            Name(_HID, "QEMU0002")
> >>+            Name(_CID, "VM_Gen_Counter")
> >>+            Name(_DDN, "VM_Gen_Counter")
> >>+
> >>+            ACPI_EXTRACT_NAME_DWORD_CONST ssdt_acpi_vm_gid_addr
> >>+            Name(VGIA, VMGENID_BASE_ADDRESS)
> >>+
> >>+            OperationRegion(VGID, SystemMemory,
> >>+                VMGENID_BASE_ADDRESS, VMGENID_BASE_ADDR_LEN)
> >>+
> >>+            Name(_CRS, ResourceTemplate() {
> >>+                Memory32Fixed(ReadOnly,
> >>+                    VMGENID_BASE_ADDRESS, VMGENID_BASE_ADDR_LEN)
> >>+            })
> >>+
> >>+            Method(_STA, 0, NotSerialized) {
> >>+                Store(VGIA, Local0)
> >>+                If (LEqual(Local0, Zero)) {
> >>+                    Return (0x00)
> >>+                } Else {
> >>+                    Return (0x0F)
> >>+                }
> >>+            }
> >>+
> >>+            Method(ADDR, 0, Serialized) {
> >>+                Store(Package(2) { }, Local0)
> >>+                Store(VGIA, Index(Local0, 0))
> >>+                Store(0x0000, Index(Local0, 1))
> >>+                return (Local0)
> >>+            }
> >>+        }
> >>+    }
> >>+
> >>      External(MEMORY_SLOT_NOTIFY_METHOD, MethodObj)
> >>      Scope(\_SB.PCI0) {
> >>          Device(MEMORY_HOTPLUG_DEVICE) {
> >>diff --git a/hw/i386/ssdt-misc.hex.generated b/hw/i386/ssdt-misc.hex.generated
> >>index ba4268a..f0b7a27 100644
> >>--- a/hw/i386/ssdt-misc.hex.generated
> >>+++ b/hw/i386/ssdt-misc.hex.generated
> >>@@ -26,7 +26,7 @@ static unsigned char ssdp_misc_aml[] = {
> >>  0x0,
> >>  0x0,
> >>  0x1,
> >>-0x8b,
> >>+0x80,
> >>  0x42,
> >>  0x58,
> >>  0x50,
> >>@@ -49,9 +49,9 @@ static unsigned char ssdp_misc_aml[] = {
> >>  0x4e,
> >>  0x54,
> >>  0x4c,
> >>-0x15,
> >>-0x11,
> >>-0x13,
> >>+0x28,
> >>+0x8,
> >>+0x14,
> >>  0x20,
> >>  0x10,
> >>  0x42,
> >>diff --git a/hw/isa/lpc_ich9.c b/hw/isa/lpc_ich9.c
> >>index 530b074..3a012fa 100644
> >>--- a/hw/isa/lpc_ich9.c
> >>+++ b/hw/isa/lpc_ich9.c
> >>@@ -678,6 +678,7 @@ static void ich9_lpc_class_init(ObjectClass *klass, void *data)
> >>      hc->plug = ich9_device_plug_cb;
> >>      hc->unplug_request = ich9_device_unplug_request_cb;
> >>      adevc->ospm_status = ich9_pm_ospm_status;
> >>+    adevc->vm_generation_id_changed = ich9_vm_generation_id_changed;
> >>  }
> >>
> >>  static const TypeInfo ich9_lpc_info = {
> >>diff --git a/hw/misc/Makefile.objs b/hw/misc/Makefile.objs
> >>index 979e532..c18b800 100644
> >>--- a/hw/misc/Makefile.objs
> >>+++ b/hw/misc/Makefile.objs
> >>@@ -41,3 +41,4 @@ obj-$(CONFIG_SLAVIO) += slavio_misc.o
> >>  obj-$(CONFIG_ZYNQ) += zynq_slcr.o
> >>
> >>  obj-$(CONFIG_PVPANIC) += pvpanic.o
> >>+obj-$(CONFIG_VMGENID) += vmgenid.o
> >>diff --git a/hw/misc/vmgenid.c b/hw/misc/vmgenid.c
> >>new file mode 100644
> >>index 0000000..01aacd4
> >>--- /dev/null
> >>+++ b/hw/misc/vmgenid.c
> >>@@ -0,0 +1,116 @@
> >>+/*
> >>+ *  Virtual Machine Generation ID Device
> >>+ *
> >>+ *  Copyright (C) 2014 Red Hat Inc.
> >>+ *
> >>+ *  Authors: Gal Hammer <ghammer@redhat.com>
> >>+ *
> >>+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
> >>+ * See the COPYING file in the top-level directory.
> >>+ *
> >>+ */
> >>+
> >>+#include "hw/i386/pc.h"
> >>+#include "hw/sysbus.h"
> >>+#include "hw/misc/vmgenid.h"
> >>+#include "hw/acpi/acpi_dev_interface.h"
> >>+
> >>+#define PROPERTY_UUID "uuid"
> >>+
> >>+#define VMGENID(obj) OBJECT_CHECK(VmGenIdState, (obj), VMGENID_DEVICE)
> >>+
> >>+typedef struct VmGenIdState {
> >>+    SysBusDevice parent_obj;
> >>+    MemoryRegion iomem;
> >>+    uint8_t guid[16];
> >>+    bool guid_set;
> >>+} VmGenIdState;
> >>+
> >>+bool vm_generation_id_set(void)
> >>+{
> >>+    Object *obj = object_resolve_path_type("", VMGENID_DEVICE, NULL);
> >>+    VmGenIdState *s = VMGENID(obj);
> >>+
> >>+    if (!obj) {
> >>+        return false;
> >>+    }
> >>+    return s->guid_set;
> >>+}
> >>+
> >>+static uint64_t vmgenid_ram_read(void *opaque, hwaddr addr,
> >>+                                 unsigned size)
> >>+{
> >>+    VmGenIdState *s = VMGENID(opaque);
> >>+    uint64_t value;
> >>+
> >>+    memcpy(&value, s->guid + addr, size);
> >>+    return value;
> >>+}
> >>+
> >>+static const MemoryRegionOps vmgenid_ram_ops = {
> >>+    .read = vmgenid_ram_read,
> >>+    .valid = {
> >>+        .min_access_size = 4,
> >>+        .max_access_size = 4,
> >>+    },
> >>+    .endianness = DEVICE_NATIVE_ENDIAN,
> >>+};
> >>+
> >>+static void vmgenid_set_uuid(Object *obj, const char *value, Error **errp)
> >>+{
> >>+    VmGenIdState *s = VMGENID(obj);
> >>+    Object *acpi_obj;
> >>+    bool first_set = !s->guid_set;
> >>+
> >>+    if (qemu_uuid_parse(value, s->guid) < 0) {
> >>+        error_setg(errp, "Fail to parse UUID string.");
> >>+        return;
> >>+    }
> >>+    s->guid_set = true;
> >>+
> >>+    /* Skip the acpi notification when setting the vm generation id for the
> >>+     * first time. This is done because in a q35 machine the gpe register is
> >>+     * allocated after the device is initialized. */
> >>+    if (!first_set) {
> >>+        acpi_obj = object_resolve_path_type("", TYPE_ACPI_DEVICE_IF, NULL);
> >>+        if (acpi_obj) {
> >>+            AcpiDeviceIfClass *adevc = ACPI_DEVICE_IF_GET_CLASS(acpi_obj);
> >>+            AcpiDeviceIf *adev = ACPI_DEVICE_IF(acpi_obj);
> >>+
> >>+            adevc->vm_generation_id_changed(adev);
> >>+        }
> >>+    }
> >>+}
> >>+
> >>+static void vmgenid_init(Object *obj)
> >>+{
> >>+    SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
> >>+    VmGenIdState *s = VMGENID(obj);
> >>+
> >>+    memory_region_init_io(&s->iomem, obj, &vmgenid_ram_ops, s, "vgid", 16);
> >>+    sysbus_init_mmio(sbd, &s->iomem);
> >
> >This will cause an exit on each access to the GID.
> >I'm guessing this is too expensive.
> 
> Yes, it does cause an exit, but I don't think it is critical because the GID
> is rarely read by the guest OS. As far as I can tell it is only accessed on
> reboot and when the GID is changed.
> 
> Do you prefer that I'll use the cpu_physical_memory_write function? Or do
> you have a diffrent idea on how to implement it?

I think you need to get hold of some RAM, and use that.  For example,
allocate a buffer, pass the address to host in _INI.

> >
> >
> >>+
> >>+    object_property_add_str(obj, PROPERTY_UUID, NULL, vmgenid_set_uuid, NULL);
> >>+}
> >>+
> >>+static void vmgenid_class_init(ObjectClass *klass, void *data)
> >>+{
> >>+    DeviceClass *dc = DEVICE_CLASS(klass);
> >>+
> >>+    set_bit(DEVICE_CATEGORY_MISC, dc->categories);
> >>+}
> >>+
> >>+static const TypeInfo vmgenid_device_info = {
> >>+    .name          = VMGENID_DEVICE,
> >>+    .parent        = TYPE_SYS_BUS_DEVICE,
> >>+    .instance_size = sizeof(VmGenIdState),
> >>+    .instance_init = vmgenid_init,
> >>+    .class_init    = vmgenid_class_init,
> >>+};
> >>+
> >>+static void vmgenid_register_types(void)
> >>+{
> >>+    type_register_static(&vmgenid_device_info);
> >>+}
> >>+
> >>+type_init(vmgenid_register_types)
> >>diff --git a/include/hw/acpi/acpi.h b/include/hw/acpi/acpi.h
> >>index 1f678b4..9373b4d 100644
> >>--- a/include/hw/acpi/acpi.h
> >>+++ b/include/hw/acpi/acpi.h
> >>@@ -185,4 +185,6 @@ unsigned acpi_table_len(void *current);
> >>  void acpi_table_add(const QemuOpts *opts, Error **errp);
> >>  void acpi_table_add_builtin(const QemuOpts *opts, Error **errp);
> >>
> >>+void acpi_vm_generation_id_changed(ACPIREGS *acpi_regs, qemu_irq irq);
> >>+
> >>  #endif /* !QEMU_HW_ACPI_H */
> >>diff --git a/include/hw/acpi/acpi_dev_interface.h b/include/hw/acpi/acpi_dev_interface.h
> >>index f245f8d..757ce60 100644
> >>--- a/include/hw/acpi/acpi_dev_interface.h
> >>+++ b/include/hw/acpi/acpi_dev_interface.h
> >>@@ -28,6 +28,9 @@ typedef struct AcpiDeviceIf {
> >>   * ospm_status: returns status of ACPI device objects, reported
> >>   *              via _OST method if device supports it.
> >>   *
> >>+ * vm_generation_id_changed: notify the guest that it generation
> >>+ *                           id was changed.
> >>+ *
> >>   * Interface is designed for providing unified interface
> >>   * to generic ACPI functionality that could be used without
> >>   * knowledge about internals of actual device that implements
> >>@@ -39,5 +42,6 @@ typedef struct AcpiDeviceIfClass {
> >>
> >>      /* <public> */
> >>      void (*ospm_status)(AcpiDeviceIf *adev, ACPIOSTInfoList ***list);
> >>+    void (*vm_generation_id_changed)(AcpiDeviceIf *adev);
> >>  } AcpiDeviceIfClass;
> >>  #endif
> >>diff --git a/include/hw/acpi/ich9.h b/include/hw/acpi/ich9.h
> >>index 7e42448..3b4eed5 100644
> >>--- a/include/hw/acpi/ich9.h
> >>+++ b/include/hw/acpi/ich9.h
> >>@@ -62,4 +62,6 @@ void ich9_pm_add_properties(Object *obj, ICH9LPCPMRegs *pm, Error **errp);
> >>  void ich9_pm_device_plug_cb(ICH9LPCPMRegs *pm, DeviceState *dev, Error **errp);
> >>
> >>  void ich9_pm_ospm_status(AcpiDeviceIf *adev, ACPIOSTInfoList ***list);
> >>+
> >>+void ich9_vm_generation_id_changed(AcpiDeviceIf *adev);
> >>  #endif /* HW_ACPI_ICH9_H */
> >>diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
> >>index 1c2602e..87912b2 100644
> >>--- a/include/hw/i386/pc.h
> >>+++ b/include/hw/i386/pc.h
> >>@@ -290,6 +290,9 @@ void pc_system_firmware_init(MemoryRegion *rom_memory,
> >>  /* pvpanic.c */
> >>  uint16_t pvpanic_port(void);
> >>
> >>+/* vmgenid.c */
> >>+bool vm_generation_id_set(void);
> >>+
> >>  /* e820 types */
> >>  #define E820_RAM        1
> >>  #define E820_RESERVED   2
> >>diff --git a/include/hw/misc/vmgenid.h b/include/hw/misc/vmgenid.h
> >>new file mode 100644
> >>index 0000000..3d44421
> >>--- /dev/null
> >>+++ b/include/hw/misc/vmgenid.h
> >>@@ -0,0 +1,21 @@
> >>+/*
> >>+ *  Virtual Machine Generation ID Device
> >>+ *
> >>+ *  Copyright (C) 2014 Red Hat Inc.
> >>+ *
> >>+ *  Authors: Gal Hammer <ghammer@redhat.com>
> >>+ *
> >>+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
> >>+ * See the COPYING file in the top-level directory.
> >>+ *
> >>+ */
> >>+
> >>+#ifndef HW_MISC_VMGENID_H
> >>+#define HW_MISC_VMGENID_H
> >>+
> >>+#define VMGENID_DEVICE "vmgenid"
> >>+
> >>+#define VMGENID_BASE_ADDRESS    0xfedf0000
> >>+#define VMGENID_BASE_ADDR_LEN   16
> >>+
> >>+#endif
> >>--
> >>1.9.3