[Qemu-devel] [PATCH 06/12] kvmvapic: fixing loading vmstate

[Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>]

vapic state should not be synchronized with APIC while loading,
because APIC state could be not loaded yet at that moment.
We just save vapic_paddr in APIC VMState instead of synchronization.

Signed-off-by: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru>
---
 hw/i386/kvmvapic.c              |   22 +++++++++++++++++++-
 hw/intc/apic_common.c           |   44 +++++++++++++++++++++++++++++++++++++++
 include/hw/i386/apic_internal.h |    2 +-
 3 files changed, 66 insertions(+), 2 deletions(-)

diff --git a/hw/i386/kvmvapic.c b/hw/i386/kvmvapic.c
index ee95963..3c403c5 100644
--- a/hw/i386/kvmvapic.c
+++ b/hw/i386/kvmvapic.c
@@ -351,6 +351,24 @@ static int get_kpcr_number(X86CPU *cpu)
     return kpcr.number;
 }
 
+static int vapic_enable_post_load(VAPICROMState *s, X86CPU *cpu)
+{
+    int cpu_number = get_kpcr_number(cpu);
+    hwaddr vapic_paddr;
+    static const uint8_t enabled = 1;
+
+    if (cpu_number < 0) {
+        return -1;
+    }
+    vapic_paddr = s->vapic_paddr +
+        (((hwaddr)cpu_number) << VAPIC_CPU_SHIFT);
+    cpu_physical_memory_rw(vapic_paddr + offsetof(VAPICState, enabled),
+                           (void *)&enabled, sizeof(enabled), 1);
+    s->state = VAPIC_ACTIVE;
+
+    return 0;
+}
+
 static int vapic_enable(VAPICROMState *s, X86CPU *cpu)
 {
     int cpu_number = get_kpcr_number(cpu);
@@ -731,7 +749,9 @@ static void do_vapic_enable(void *data)
     VAPICROMState *s = data;
     X86CPU *cpu = X86_CPU(first_cpu);
 
-    vapic_enable(s, cpu);
+    /* Do not synchronize with APIC, because it was not loaded yet.
+       Just call the enable function which does not have synchronization. */
+    vapic_enable_post_load(s, cpu);
 }
 
 static int vapic_post_load(void *opaque, int version_id)
diff --git a/hw/intc/apic_common.c b/hw/intc/apic_common.c
index ce3d903..8d672bd 100644
--- a/hw/intc/apic_common.c
+++ b/hw/intc/apic_common.c
@@ -345,6 +345,39 @@ 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 bool apic_common_vapic_paddr_needed(void *opaque)
+{
+    APICCommonState *s = APIC_COMMON(opaque);
+    return s->vapic_paddr != 0;
+}
+
+static const VMStateDescription vmstate_apic_common_vapic_paddr = {
+    .name = "apic_vapic_paddr",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT64(vapic_paddr, APICCommonState),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
 static const VMStateDescription vmstate_apic_common = {
     .name = "apic",
     .version_id = 3,
@@ -375,6 +408,17 @@ 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,
+        },
+        {
+            .vmsd = &vmstate_apic_common_vapic_paddr,
+            .needed = apic_common_vapic_paddr_needed,
+        },
+        VMSTATE_END_OF_LIST()
     }
 };
 
diff --git a/include/hw/i386/apic_internal.h b/include/hw/i386/apic_internal.h
index 83e2a42..df4381c 100644
--- a/include/hw/i386/apic_internal.h
+++ b/include/hw/i386/apic_internal.h
@@ -124,7 +124,7 @@ struct APICCommonState {
 
     uint32_t vapic_control;
     DeviceState *vapic;
-    hwaddr vapic_paddr; /* note: persistence via kvmvapic */
+    hwaddr vapic_paddr;
 };
 
 typedef struct VAPICState {