diff -r e6f751ed8e38 xen/arch/x86/apic.c
--- a/xen/arch/x86/apic.c	Tue Mar 09 10:00:37 2010 +0000
+++ b/xen/arch/x86/apic.c	Fri May 28 12:28:22 2010 +0200
@@ -209,6 +209,11 @@ void clear_local_APIC(void)
      */
     v = apic_read(APIC_LVTT);
     apic_write_around(APIC_LVTT, v | APIC_LVT_MASKED);
+
+    /* Workaround AMD Erratum 411. Please refer to AMD
+    revision guide for more details. */
+    apic_write_around(APIC_TMICT, 0x0);
+
     v = apic_read(APIC_LVT0);
     apic_write_around(APIC_LVT0, v | APIC_LVT_MASKED);
     v = apic_read(APIC_LVT1);
@@ -1187,6 +1192,10 @@ void disable_APIC_timer(void)
         
         v = apic_read(APIC_LVTT);
         apic_write_around(APIC_LVTT, v | APIC_LVT_MASKED);
+
+        /* Workaround AMD Erratum 411. Please refer to AMD
+        revision guide for more details. */
+        apic_write_around(APIC_TMICT, 0x0);
     }
 }