[Xen-devel] [PATCH] x86 hvm: fix missing ticks bug of c/s 20218

[Kouya Shimura <kouya@xxxxxxxxxxxxxx>]

With c/s 20218, timer ticks might be missed when IRQs of a timer are queued. 
Next scheduled time is accumulated wrongly.

Thanks to Christoph for the report.

Thanks,
Kouya

Signed-off-by: Kouya Shimura <kouya@xxxxxxxxxxxxxx>
Reported-by: Christoph Egger <Christoph.Egger@xxxxxxx>

diff -r 72d130772f36 xen/arch/x86/hvm/vpt.c
--- a/xen/arch/x86/hvm/vpt.c    Wed Sep 16 09:30:41 2009 +0100
+++ b/xen/arch/x86/hvm/vpt.c    Fri Sep 18 13:54:12 2009 +0900
@@ -308,9 +308,6 @@ void pt_intr_post(struct vcpu *v, struct
     }
     else
     {
-        pt->scheduled += pt->period;
-        pt_process_missed_ticks(pt);
-
         if ( mode_is(v->domain, one_missed_tick_pending) ||
              mode_is(v->domain, no_missed_ticks_pending) )
         {
@@ -324,7 +321,12 @@ void pt_intr_post(struct vcpu *v, struct
         }
 
         if ( pt->pending_intr_nr == 0 )
+        {
+            pt->scheduled += pt->period;
+            pt_process_missed_ticks(pt);
+            pt->do_not_freeze = 0;
             set_timer(&pt->timer, pt->scheduled);
+        }
     }
 
     if ( mode_is(v->domain, delay_for_missed_ticks) &&

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