diff -r 4054cd60895b xen/arch/x86/hvm/vpt.c
--- a/xen/arch/x86/hvm/vpt.c	Mon Dec 10 13:49:22 2007 +0000
+++ b/xen/arch/x86/hvm/vpt.c	Tue Dec 11 23:51:08 2007 +0800
@@ -95,7 +95,7 @@ void pt_save_timer(struct vcpu *v)
     spin_lock(&v->arch.hvm_vcpu.tm_lock);
 
     list_for_each_entry ( pt, head, list )
-        if ( !pt->do_not_freeze )
+        if ( !pt->do_not_freeze && !pt->one_shot )
             stop_timer(&pt->timer);
 
     pt_freeze_time(v);
@@ -112,6 +112,8 @@ void pt_restore_timer(struct vcpu *v)
 
     list_for_each_entry ( pt, head, list )
     {
+        if ( pt->one_shot )
+            continue;
         pt_process_missed_ticks(pt);
         set_timer(&pt->timer, pt->scheduled);
     }