diff -r 8e2690dbec49 xen/arch/x86/traps.c
--- a/xen/arch/x86/traps.c	Sat Mar 24 13:13:49 2012 -0400
+++ b/xen/arch/x86/traps.c	Wed Mar 28 16:27:31 2012 -0400
@@ -1746,7 +1746,8 @@ void (*pv_post_outb_hook)(unsigned int p
 static inline uint64_t guest_misc_enable(uint64_t val)
 {
     val &= ~(MSR_IA32_MISC_ENABLE_PERF_AVAIL |
-             MSR_IA32_MISC_ENABLE_MONITOR_ENABLE);
+             MSR_IA32_MISC_ENABLE_MONITOR_ENABLE |
+             MSR_IA32_MISC_ENABLE_TURBO);
     val |= MSR_IA32_MISC_ENABLE_BTS_UNAVAIL |
            MSR_IA32_MISC_ENABLE_PEBS_UNAVAIL |
            MSR_IA32_MISC_ENABLE_XTPR_DISABLE;
diff -r 8e2690dbec49 xen/include/asm-x86/msr-index.h
--- a/xen/include/asm-x86/msr-index.h	Sat Mar 24 13:13:49 2012 -0400
+++ b/xen/include/asm-x86/msr-index.h	Wed Mar 28 16:27:31 2012 -0400
@@ -327,6 +327,7 @@
 #define MSR_IA32_MISC_ENABLE_MONITOR_ENABLE (1<<18)
 #define MSR_IA32_MISC_ENABLE_LIMIT_CPUID  (1<<22)
 #define MSR_IA32_MISC_ENABLE_XTPR_DISABLE (1<<23)
+#define MSR_IA32_MISC_ENABLE_TURBO        (1<<38)
 
 #define MSR_IA32_TSC_DEADLINE		0x000006E0
 #define MSR_IA32_ENERGY_PERF_BIAS	0x000001b0