Index: /trunk/include/VBox/x86.h
===================================================================
--- /trunk/include/VBox/x86.h	(revision 26656)
+++ /trunk/include/VBox/x86.h	(revision 26657)
@@ -467,4 +467,14 @@
 /** Bit 31 - PBE - Pending Break Enabled. */
 #define X86_CPUID_FEATURE_EDX_PBE       RT_BIT(31)
+/** @} */
+
+/** @name CPUID Feature information.
+ * CPUID query with EAX=5.
+ * @{
+ */
+/** ECX Bit 0 - MWAITEXT - Supports mwait/monitor extensions or not. */
+#define X86_CPUID_MWAIT_ECX_EXT            RT_BIT(0)
+/** ECX Bit 1 - MWAITBREAK - Break mwait for external interrupt even if EFLAGS.IF=0. */
+#define X86_CPUID_MWAIT_ECX_BREAKIRQIF0    RT_BIT(1)
 /** @} */