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

[Kouya Shimura <kouya@xxxxxxxxxxxxxx>]

Although c/s 20229 fixes missing ticks issue in c/s 20218,
it's not enough.

- set a timer to the next period more straightforwardly.
- fix an unexpected behavior of both timer_mode=2 and timer_mode=3.
  extra interrupts might be delivered to a guest.

Signed-off-by: Kouya Shimura <kouya@xxxxxxxxxxxxxx>

diff -r 0f8376078dc1 xen/arch/x86/hvm/vpt.c
--- a/xen/arch/x86/hvm/vpt.c    Wed Sep 23 18:19:30 2009 +0100
+++ b/xen/arch/x86/hvm/vpt.c    Thu Sep 24 17:19:56 2009 +0900
@@ -313,20 +313,23 @@ void pt_intr_post(struct vcpu *v, struct
         if ( mode_is(v->domain, one_missed_tick_pending) ||
              mode_is(v->domain, no_missed_ticks_pending) )
         {
+            pt_process_missed_ticks(pt);
+            set_timer(&pt->timer, pt->scheduled);
+
             pt->last_plt_gtime = hvm_get_guest_time(v);
             pt->pending_intr_nr = 0; /* 'collapse' all missed ticks */
         }
         else
         {
+            s_time_t now = NOW();
+
+            if ( pt->scheduled > now )
+            {
+                set_timer(&pt->timer, pt->scheduled);
+                pt->pending_intr_nr = 0;
+            }
+
             pt->last_plt_gtime += pt->period;
-            pt->pending_intr_nr--;
-        }
-
-        if ( pt->pending_intr_nr == 0 )
-        {
-            pt_process_missed_ticks(pt);
-            pt->do_not_freeze = 0;
-            set_timer(&pt->timer, pt->scheduled);
         }
     }
 

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