[Qemu-devel] [PULL 13/21] apic_common: vapic_paddr synchronization fix

[Paolo Bonzini <pbonzini@redhat.com>]

From: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>

This patch postpones vapic_paddr initialization, which is performed
during migration. When vapic_paddr is synchronized within the migration
process, apic_common functions could operate with incorrect apic state,
if it hadn't loaded yet. This patch postpones the synchronization until
the virtual machine is started, ensuring that the whole virtual machine
state has been loaded.

Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>
Tested-by: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 hw/i386/kvmvapic.c | 37 ++++++++++++++++++++++++++-----------
 1 file changed, 26 insertions(+), 11 deletions(-)

diff --git a/hw/i386/kvmvapic.c b/hw/i386/kvmvapic.c
index ee95963..2cca7a4 100644
--- a/hw/i386/kvmvapic.c
+++ b/hw/i386/kvmvapic.c
@@ -59,6 +59,7 @@ typedef struct VAPICROMState {
     GuestROMState rom_state;
     size_t rom_size;
     bool rom_mapped_writable;
+    VMChangeStateEntry *vmsentry;
 } VAPICROMState;
 
 #define TYPE_VAPIC "kvmvapic"
@@ -734,11 +735,34 @@ static void do_vapic_enable(void *data)
     vapic_enable(s, cpu);
 }
 
-static int vapic_post_load(void *opaque, int version_id)
+static void kvmvapic_vm_state_change(void *opaque, int running,
+                                     RunState state)
 {
     VAPICROMState *s = opaque;
     uint8_t *zero;
 
+    if (!running) {
+        return;
+    }
+
+    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_write(s->vapic_paddr, zero,
+                                      s->rom_state.vapic_size);
+            g_free(zero);
+        }
+    }
+
+    qemu_del_vm_change_state_handler(s->vmsentry);
+}
+
+static int vapic_post_load(void *opaque, int version_id)
+{
+    VAPICROMState *s = opaque;
+
     /*
      * The old implementation of qemu-kvm did not provide the state
      * VAPIC_STANDBY. Reconstruct it.
@@ -752,17 +776,8 @@ static int vapic_post_load(void *opaque, int version_id)
             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_write(s->vapic_paddr, zero,
-                                      s->rom_state.vapic_size);
-            g_free(zero);
-        }
-    }
 
+    s->vmsentry = qemu_add_vm_change_state_handler(kvmvapic_vm_state_change, s);
     return 0;
 }
 
-- 
2.1.0