[Qemu-devel] [PATCH v2 1/2] Add machine type pc-1.0-qemu-kvm for live migrate compatibility with qemu-kvm

[Alex Bligh <alex@alex.org.uk>]

Add a machine type pc-1.0-qemu-kvm for live migrate compatibility
with qemu-kvm version 1.0.

Signed-off-by: Alex Bligh <alex@alex.org.uk>
---
 hw/acpi/piix4.c          |   49 ++++++++++++++++++++++++++++++++++++++++++++--
 hw/i386/pc_piix.c        |   31 +++++++++++++++++++++++++++++
 hw/timer/i8254_common.c  |   41 ++++++++++++++++++++++++++++++++++++++
 include/hw/acpi/piix4.h  |    1 +
 include/hw/timer/i8254.h |    2 ++
 5 files changed, 122 insertions(+), 2 deletions(-)

diff --git a/hw/acpi/piix4.c b/hw/acpi/piix4.c
index b72b34e..708db79 100644
--- a/hw/acpi/piix4.c
+++ b/hw/acpi/piix4.c
@@ -267,8 +267,9 @@ static const VMStateDescription vmstate_memhp_state = {
 };
 
 /* qemu-kvm 1.2 uses version 3 but advertised as 2
- * To support incoming qemu-kvm 1.2 migration, change version_id
- * and minimum_version_id to 2 below (which breaks migration from
+ * To support incoming qemu-kvm 1.2 migration, we support
+ * via a command line option a change to minimum_version_id
+ * of 2 in a _compat structure (which breaks migration from
  * qemu 1.2).
  *
  */
@@ -307,6 +308,34 @@ static const VMStateDescription vmstate_acpi = {
     }
 };
 
+static const VMStateDescription vmstate_acpi_compat = {
+    .name = "piix4_pm",
+    .version_id = 3,
+    .minimum_version_id = 2,
+    .minimum_version_id_old = 1,
+    .load_state_old = acpi_load_old,
+    .post_load = vmstate_acpi_post_load,
+    .fields      = (VMStateField[]) {
+        VMSTATE_PCI_DEVICE(parent_obj, PIIX4PMState),
+        VMSTATE_UINT16(ar.pm1.evt.sts, PIIX4PMState),
+        VMSTATE_UINT16(ar.pm1.evt.en, PIIX4PMState),
+        VMSTATE_UINT16(ar.pm1.cnt.cnt, PIIX4PMState),
+        VMSTATE_STRUCT(apm, PIIX4PMState, 0, vmstate_apm, APMState),
+        VMSTATE_TIMER(ar.tmr.timer, PIIX4PMState),
+        VMSTATE_INT64(ar.tmr.overflow_time, PIIX4PMState),
+        VMSTATE_STRUCT(ar.gpe, PIIX4PMState, 2, vmstate_gpe, ACPIGPE),
+        VMSTATE_STRUCT_TEST(
+            acpi_pci_hotplug.acpi_pcihp_pci_status[ACPI_PCIHP_BSEL_DEFAULT],
+            PIIX4PMState,
+            vmstate_test_no_use_acpi_pci_hotplug,
+            2, vmstate_pci_status,
+            struct AcpiPciHpPciStatus),
+        VMSTATE_PCI_HOTPLUG(acpi_pci_hotplug, PIIX4PMState,
+                            vmstate_test_use_acpi_pci_hotplug),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
 static void piix4_reset(void *opaque)
 {
     PIIX4PMState *s = opaque;
@@ -619,6 +648,22 @@ static void piix4_pm_class_init(ObjectClass *klass, void *data)
     adevc->ospm_status = piix4_ospm_status;
 }
 
+void piix4_pm_class_fix_compat(void)
+{
+    GSList *el, *devices = object_class_get_list(TYPE_DEVICE, false);
+    /*
+     * Change the vmstate field in this class and any derived classes
+     * if not overriden. As no other classes should be using this
+     * vmstate, we can simply iterate the class list
+     */
+    for (el = devices; el; el = el->next) {
+        DeviceClass *dc = el->data;
+        if (dc->vmsd == &vmstate_acpi) {
+            dc->vmsd = &vmstate_acpi_compat;
+        }
+    }
+}
+
 static const TypeInfo piix4_pm_info = {
     .name          = TYPE_PIIX4_PM,
     .parent        = TYPE_PCI_DEVICE,
diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index 7081c08..e400ea6 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -49,6 +49,8 @@
 #include "hw/acpi/acpi.h"
 #include "cpu.h"
 #include "qemu/error-report.h"
+#include "hw/acpi/piix4.h"
+#include "hw/timer/i8254.h"
 #ifdef CONFIG_XEN
 #  include <xen/hvm/hvm_info_table.h>
 #endif
@@ -386,6 +388,15 @@ static void pc_init_pci_1_2(MachineState *machine)
     pc_init_pci(machine);
 }
 
+/* PC machine init function for qemu-kvm 1.0 */
+static void pc_init_pci_1_2_qemu_kvm(MachineState *machine)
+{
+    piix4_pm_class_fix_compat();
+    pit_common_class_fix_compat();
+    pc_compat_1_2(machine);
+    pc_init_pci(machine);
+}
+
 /* PC init function for pc-0.10 to pc-0.13 */
 static void pc_init_pci_no_kvmclock(MachineState *machine)
 {
@@ -644,6 +655,25 @@ static QEMUMachine pc_machine_v1_0 = {
     .hw_version = "1.0",
 };
 
+#define PC_COMPAT_1_0_QEMU_KVM \
+        PC_COMPAT_1_0,\
+        {\
+            .driver   = "cirrus-vga",\
+            .property = "vgamem_mb",\
+            .value    = stringify(16),\
+        }
+
+static QEMUMachine pc_machine_v1_0_qemu_kvm = {
+    PC_I440FX_1_2_MACHINE_OPTIONS,
+    .name = "pc-1.0-qemu-kvm",
+    .init = pc_init_pci_1_2_qemu_kvm,
+    .compat_props = (GlobalProperty[]) {
+        PC_COMPAT_1_0_QEMU_KVM,
+        { /* end of list */ }
+    },
+    .hw_version = "1.0",
+};
+
 #define PC_COMPAT_0_15 \
         PC_COMPAT_1_0
 
@@ -886,6 +916,7 @@ static void pc_machine_init(void)
     qemu_register_pc_machine(&pc_machine_v1_2);
     qemu_register_pc_machine(&pc_machine_v1_1);
     qemu_register_pc_machine(&pc_machine_v1_0);
+    qemu_register_pc_machine(&pc_machine_v1_0_qemu_kvm);
     qemu_register_pc_machine(&pc_machine_v0_15);
     qemu_register_pc_machine(&pc_machine_v0_14);
     qemu_register_pc_machine(&pc_machine_v0_13);
diff --git a/hw/timer/i8254_common.c b/hw/timer/i8254_common.c
index 07345f6..511ea05 100644
--- a/hw/timer/i8254_common.c
+++ b/hw/timer/i8254_common.c
@@ -275,6 +275,29 @@ static const VMStateDescription vmstate_pit_common = {
     }
 };
 
+static const VMStateDescription vmstate_pit_common_compat = {
+    .name = "i8254",
+    .version_id = 3,
+    .minimum_version_id = 2,
+    .minimum_version_id_old = 1,
+    .load_state_old = pit_load_old,
+    .pre_save = pit_dispatch_pre_save,
+    .post_load = pit_dispatch_post_load,
+    .fields = (VMStateField[]) {
+        /* qemu-kvm version_id=2 had 'flags' here which is equivalent
+         * This fixes incoming migration from qemu-kvm 1.0, but breaks
+         * incoming migration from qemu < 1.1
+         */
+        /* VMSTATE_UINT32_V(channels[0].irq_disabled, PITCommonState, 3), */
+        VMSTATE_UINT32(channels[0].irq_disabled, PITCommonState),
+        VMSTATE_STRUCT_ARRAY(channels, PITCommonState, 3, 2,
+                             vmstate_pit_channel, PITChannelState),
+        VMSTATE_INT64(channels[0].next_transition_time,
+                      PITCommonState), /* formerly irq_timer */
+        VMSTATE_END_OF_LIST()
+    }
+};
+
 static void pit_common_class_init(ObjectClass *klass, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(klass);
@@ -289,6 +312,24 @@ static void pit_common_class_init(ObjectClass *klass, void *data)
     dc->cannot_instantiate_with_device_add_yet = true;
 }
 
+void pit_common_class_fix_compat(void)
+{
+    GSList *el, *devices = object_class_get_list(TYPE_DEVICE, false);
+    /*
+     * Change the vmstate field in this class and any derived classes
+     * if not overriden. As no other classes should be using this
+     * vmstate, we can simply iterate the class list
+     */
+    for (el = devices; el; el = el->next) {
+        DeviceClass *dc = el->data;
+        if (dc->vmsd == &vmstate_pit_common) {
+            dc->vmsd = &vmstate_pit_common_compat;
+        }
+    }
+
+    g_slist_free(devices);
+}
+
 static const TypeInfo pit_common_type = {
     .name          = TYPE_PIT_COMMON,
     .parent        = TYPE_ISA_DEVICE,
diff --git a/include/hw/acpi/piix4.h b/include/hw/acpi/piix4.h
index 65e6fd7..811d88f 100644
--- a/include/hw/acpi/piix4.h
+++ b/include/hw/acpi/piix4.h
@@ -4,5 +4,6 @@
 #include "qemu/typedefs.h"
 
 Object *piix4_pm_find(void);
+void piix4_pm_class_fix_compat(void);
 
 #endif
diff --git a/include/hw/timer/i8254.h b/include/hw/timer/i8254.h
index 4349033..0126424 100644
--- a/include/hw/timer/i8254.h
+++ b/include/hw/timer/i8254.h
@@ -72,4 +72,6 @@ static inline ISADevice *kvm_pit_init(ISABus *bus, int base)
 void pit_set_gate(ISADevice *dev, int channel, int val);
 void pit_get_channel_info(ISADevice *dev, int channel, PITChannelInfo *info);
 
+void pit_common_class_fix_compat(void);
+
 #endif /* !HW_I8254_H */
-- 
1.7.9.5