diff -Nru a/xen/include/asm-ia64/event.h b/xen/include/asm-ia64/event.h
--- /dev/null	Wed Dec 31 16:00:00 1969
+++ b/xen/include/asm-ia64/event.h	Wed Jun 15 13:24:58 2005
@@ -0,0 +1,16 @@
+/******************************************************************************
+ * event.h
+ *
+ * A nice interface for passing asynchronous events to guest OSes.
+ * (architecture-dependent part)
+ *
+ */
+
+#ifndef __ASM_EVENT_H__
+#define __ASM_EVENT_H__
+
+static inline void evtchn_notify(struct vcpu *v)
+{
+}
+
+#endif
diff -Nru a/xen/include/asm-x86/event.h b/xen/include/asm-x86/event.h
--- /dev/null	Wed Dec 31 16:00:00 1969
+++ b/xen/include/asm-x86/event.h	Wed Jun 15 13:24:58 2005
@@ -0,0 +1,16 @@
+/******************************************************************************
+ * event.h
+ *
+ * A nice interface for passing asynchronous events to guest OSes.
+ * (architecture-dependent part)
+ *
+ */
+
+#ifndef __ASM_EVENT_H__
+#define __ASM_EVENT_H__
+
+static inline void evtchn_notify(struct vcpu *v)
+{
+}
+
+#endif
diff -Nru a/xen/include/xen/event.h b/xen/include/xen/event.h
--- a/xen/include/xen/event.h	Wed Jun 15 13:24:58 2005
+++ b/xen/include/xen/event.h	Wed Jun 15 13:24:58 2005
@@ -13,6 +13,7 @@
 #include <xen/sched.h>
 #include <xen/smp.h>
 #include <asm/bitops.h>
+#include <asm/event.h>
 
 /*
  * EVENT-CHANNEL NOTIFICATIONS
@@ -34,6 +35,7 @@
     {
         /* The VCPU pending flag must be set /after/ update to evtchn-pend. */
         set_bit(0, &v->vcpu_info->evtchn_upcall_pending);
+        evtchn_notify(v);
 
         /*
          * NB1. 'vcpu_flags' and 'processor' must be checked /after/ update of