[Xen-devel] [PATCH] common/vm_event: synchronize vCPU state in vm_event_resume()

[Razvan Cojocaru <rcojocaru@xxxxxxxxxxxxxxx>]

Vm_event_vcpu_pause() needs to use vcpu_pause_nosync() in order
for the current vCPU to not get stuck. A consequence of this is
that the custom vm_event response handlers will not always see
the real vCPU state in v->arch.user_regs. This patch makes sure
that the state is always synchronized in vm_event_resume, before
any handlers have been called. This problem especially affects
vm_event_set_registers().

Signed-off-by: Razvan Cojocaru <rcojocaru@xxxxxxxxxxxxxxx>
---
 xen/common/vm_event.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/xen/common/vm_event.c b/xen/common/vm_event.c
index 941345b..22cafd4 100644
--- a/xen/common/vm_event.c
+++ b/xen/common/vm_event.c
@@ -388,6 +388,12 @@ void vm_event_resume(struct domain *d, struct 
vm_event_domain *ved)
         v = d->vcpu[rsp.vcpu_id];
 
         /*
+         * Make sure the vCPU state has been synchronized for the custom
+         * handlers.
+         */
+        sync_vcpu_execstate(v);
+
+        /*
          * In some cases the response type needs extra handling, so here
          * we call the appropriate handlers.
          */
-- 
1.9.1


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