[Qemu-devel] [PATCH] arm_gic_kvm: Disable live migration if not supported

[Pavel Fedin]

Currently, if the kernel does not have live migration API, the migration
will still be attempted, but vGIC save/restore functions will just not do
anything. This will result in a broken machine state.

This patch fixes the problem by patching vmstate_gic.unmigratable flag in
runtine.

Signed-off-by: Pavel Fedin <address@hidden>
---
 hw/intc/arm_gic_common.c |  2 +-
 hw/intc/arm_gic_kvm.c    | 17 ++++++-----------
 hw/intc/gic_internal.h   |  2 ++
 3 files changed, 9 insertions(+), 12 deletions(-)

diff --git a/hw/intc/arm_gic_common.c b/hw/intc/arm_gic_common.c
index 2b08175..1af4590 100644
--- a/hw/intc/arm_gic_common.c
+++ b/hw/intc/arm_gic_common.c
@@ -60,7 +60,7 @@ static const VMStateDescription vmstate_gic_irq_state = {
     }
 };
 
-static const VMStateDescription vmstate_gic = {
+VMStateDescription vmstate_gic = {
     .name = "arm_gic",
     .version_id = 12,
     .minimum_version_id = 12,
diff --git a/hw/intc/arm_gic_kvm.c b/hw/intc/arm_gic_kvm.c
index e8b2386..ad63081 100644
--- a/hw/intc/arm_gic_kvm.c
+++ b/hw/intc/arm_gic_kvm.c
@@ -307,11 +307,6 @@ static void kvm_arm_gic_put(GICState *s)
     int num_cpu;
     int num_irq;
 
-    if (!kvm_arm_gic_can_save_restore(s)) {
-            DPRINTF("Cannot put kernel gic state, no kernel interface");
-            return;
-    }
-
     /* Note: We do the restore in a slightly different order than the save
      * (where the order doesn't matter and is simply ordered according to the
      * register offset values */
@@ -411,11 +406,6 @@ static void kvm_arm_gic_get(GICState *s)
     int i;
     int cpu;
 
-    if (!kvm_arm_gic_can_save_restore(s)) {
-            DPRINTF("Cannot get kernel gic state, no kernel interface");
-            return;
-    }
-
     /*****************************************************************
      * Distributor State
      */
@@ -503,7 +493,10 @@ static void kvm_arm_gic_reset(DeviceState *dev)
     KVMARMGICClass *kgc = KVM_ARM_GIC_GET_CLASS(s);
 
     kgc->parent_reset(dev);
-    kvm_arm_gic_put(s);
+
+    if (kvm_arm_gic_can_save_restore(s)) {
+        kvm_arm_gic_put(s);
+    }
 }
 
 static void kvm_arm_gic_realize(DeviceState *dev, Error **errp)
@@ -573,6 +566,8 @@ static void kvm_arm_gic_realize(DeviceState *dev, Error 
**errp)
                             KVM_DEV_ARM_VGIC_GRP_ADDR,
                             KVM_VGIC_V2_ADDR_TYPE_CPU,
                             s->dev_fd);
+
+    vmstate_gic.unmigratable = !kvm_arm_gic_can_save_restore(s);
 }
 
 static void kvm_arm_gic_class_init(ObjectClass *klass, void *data)
diff --git a/hw/intc/gic_internal.h b/hw/intc/gic_internal.h
index 20c1e8a..e846f1b 100644
--- a/hw/intc/gic_internal.h
+++ b/hw/intc/gic_internal.h
@@ -77,6 +77,8 @@
 #define REV_11MPCORE 0
 #define REV_NVIC 0xffffffff
 
+extern VMStateDescription vmstate_gic;
+
 void gic_set_pending_private(GICState *s, int cpu, int irq);
 uint32_t gic_acknowledge_irq(GICState *s, int cpu, MemTxAttrs attrs);
 void gic_complete_irq(GICState *s, int cpu, int irq, MemTxAttrs attrs);
-- 
1.9.5.msysgit.0