x86/msr: Add MSR_MISC_FEATURE_ENABLES and RING3MWAIT bit

Define new MSR MISC_FEATURE_ENABLES (0x140).

On supported CPUs if bit 1 of this MSR is set, then calling MONITOR and
MWAIT instructions outside of ring 0 will not cause invalid-opcode
exception.

The MSR MISC_FEATURE_ENABLES is not yet documented in the SDM. Here is the
relevant documentation:

Hex   Dec  Name                     Scope
140H  320  MISC_FEATURE_ENABLES     Thread
           0    Reserved
           1    If set to 1, the MONITOR and MWAIT instructions do not
                cause invalid-opcode exceptions when executed with CPL > 0
                or in virtual-8086 mode. If MWAIT is executed when CPL > 0
                or in virtual-8086 mode, and if EAX indicates a C-state
                other than C0 or C1, the instruction operates as if EAX
                indicated the C-state C1.
           63:2 Reserved

Signed-off-by: Grzegorz Andrejczuk <grzegorz.andrejczuk@intel.com>
Cc: Piotr.Luc@intel.com
Cc: dave.hansen@linux.intel.com
Link: http://lkml.kernel.org/r/1484918557-15481-2-git-send-email-grzegorz.andrejczuk@intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index 710273c617b8d3d735d9aaacdc3349d599717204..00293a94ffaf5a68023022eb6c0b74ba5bac62ef 100644 (file)
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -543,6 +543,11 @@
 #define MSR_IA32_MISC_ENABLE_IP_PREF_DISABLE_BIT       39
 #define MSR_IA32_MISC_ENABLE_IP_PREF_DISABLE           (1ULL << MSR_IA32_MISC_ENABLE_IP_PREF_DISABLE_BIT)
 
+/* MISC_FEATURE_ENABLES non-architectural features */
+#define MSR_MISC_FEATURE_ENABLES       0x00000140
+
+#define MSR_MISC_FEATURE_ENABLES_RING3MWAIT_BIT                1
+
 #define MSR_IA32_TSC_DEADLINE          0x000006E0
 
 /* P4/Xeon+ specific */