apic_common: migrate missing fields

This patch adds missed sipi_vector and wait_for_sipi fields to a new
subsection of the vmstate of the apic_common module. Saving and loading
of these fields makes migration of the apic state deterministic.

Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>
[Initialize the field in pre_load and kvm_apic_realize. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

hw/i386/kvm/apic.c

@@ -175,6 +175,9 @@ static void kvm_apic_realize(DeviceState *dev, Error **errp)
 {
     APICCommonState *s = APIC_COMMON(dev);
 
+    /* Not used by KVM, which uses the CPU mp_state instead.  */
+    s->wait_for_sipi = 0;
+
     memory_region_init_io(&s->io_memory, NULL, &kvm_apic_io_ops, s, "kvm-apic-msi",
                           APIC_SPACE_SIZE);
 

hw/intc/apic_common.c

@@ -324,6 +324,19 @@ static void apic_common_realize(DeviceState *dev, Error **errp)
 
 }
 
+static int apic_pre_load(void *opaque)
+{
+    APICCommonState *s = APIC_COMMON(opaque);
+
+    /* The default is !cpu_is_bsp(s->cpu), but the common value is 0
+     * so that's what apic_common_sipi_needed checks for.  Reset to
+     * the value that is assumed when the apic_sipi subsection is
+     * absent.
+     */
+    s->wait_for_sipi = 0;
+    return 0;
+}
+
 static void apic_dispatch_pre_save(void *opaque)
 {
     APICCommonState *s = APIC_COMMON(opaque);
@@ -345,12 +358,30 @@ static int apic_dispatch_post_load(void *opaque, int version_id)
     return 0;
 }
 
+static bool apic_common_sipi_needed(void *opaque)
+{
+    APICCommonState *s = APIC_COMMON(opaque);
+    return s->wait_for_sipi != 0;
+}
+
+static const VMStateDescription vmstate_apic_common_sipi = {
+    .name = "apic_sipi",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_INT32(sipi_vector, APICCommonState),
+        VMSTATE_INT32(wait_for_sipi, APICCommonState),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
 static const VMStateDescription vmstate_apic_common = {
     .name = "apic",
     .version_id = 3,
     .minimum_version_id = 3,
     .minimum_version_id_old = 1,
     .load_state_old = apic_load_old,
+    .pre_load = apic_pre_load,
     .pre_save = apic_dispatch_pre_save,
     .post_load = apic_dispatch_post_load,
     .fields = (VMStateField[]) {
@@ -375,6 +406,13 @@ static const VMStateDescription vmstate_apic_common = {
         VMSTATE_INT64(timer_expiry,
                       APICCommonState), /* open-coded timer state */
         VMSTATE_END_OF_LIST()
+    },
+    .subsections = (VMStateSubsection[]) {
+        {
+            .vmsd = &vmstate_apic_common_sipi,
+            .needed = apic_common_sipi_needed,
+        },
+        VMSTATE_END_OF_LIST()
     }
 };