[PATCH v6: 1/4] x86/msr: Add R3MWAIT register and bit to msr-info.h

From: Grzegorz Andrejczuk
Date: Thu Oct 27 2016 - 10:02:34 EST


Intel Xeon Phi x200 (codenamed Knights Landing) has MSR
MISC_THD_FEATURE_ENABLE 0x140.

Setting 2nd bit of this register makes MONITOR and MWAIT instructions
do not cause invalid-opcode exception when called from ring different
than 0.

Hex Dec Name Scope
140H 320 MISC_THD_FEATURE_ENABLE 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@xxxxxxxxx>
---
arch/x86/include/asm/msr-index.h | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index 56f4c66..df9d8d3 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -540,6 +540,11 @@
#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)

+/* Intel Xeon Phi x200 ring 3 MONITOR/MWAIT */
+#define MSR_PHI_MISC_THD_FEATURE 0x00000140
+#define MSR_PHI_MISC_THD_FEATURE_R3MWAIT_BIT 1
+#define MSR_PHI_MISC_THD_FEATURE_R3MWAIT (1ULL << MSR_PHI_MISC_THD_FEATURE_R3MWAIT_BIT)
+
#define MSR_IA32_TSC_DEADLINE 0x000006E0

/* P4/Xeon+ specific */
--
2.5.1