diff -r 8f556a70ae0b xen/arch/x86/x86_emulate/x86_emulate.c
--- a/xen/arch/x86/x86_emulate/x86_emulate.c	Thu May 03 17:21:09 2012 +0100
+++ b/xen/arch/x86/x86_emulate/x86_emulate.c	Fri May 04 12:13:55 2012 +0100
@@ -372,6 +372,7 @@ typedef union {
 #define CR4_TSD   (1<<2)
 
 /* EFLAGS bit definitions. */
+#define EFLG_ID   (1<<21)
 #define EFLG_VIP  (1<<20)
 #define EFLG_VIF  (1<<19)
 #define EFLG_AC   (1<<18)
@@ -424,7 +425,7 @@ typedef union {
  * These EFLAGS bits are restored from saved value during emulation, and
  * any changes are written back to the saved value after emulation.
  */
-#define EFLAGS_MASK (EFLG_OF|EFLG_SF|EFLG_ZF|EFLG_AF|EFLG_PF|EFLG_CF)
+#define EFLAGS_MASK (EFLG_OF|EFLG_SF|EFLG_ZF|EFLG_AF|EFLG_PF|EFLG_CF|EFLG_ID)
 
 /* Before executing instruction: restore necessary bits in EFLAGS. */
 #define _PRE_EFLAGS(_sav, _msk, _tmp)                           \