Commit-ID: ae47eda905e61ef6ba0b6f79b967c9de15ca4f8e
Gitweb: http://git.kernel.org/tip/ae47eda905e61ef6ba0b6f79b967c9de15ca4f8e
Author: Grzegorz Andrejczuk <grzegorz.andrejczuk@xxxxxxxxx>
AuthorDate: Fri, 20 Jan 2017 14:22:33 +0100
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Sat, 4 Feb 2017 08:51:09 +0100
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@xxxxxxxxx>
Cc: Piotr.Luc@xxxxxxxxx
Cc: dave.hansen@xxxxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/1484918557-15481-2-git-send-email-grzegorz.andrejczuk@xxxxxxxxx
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
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 710273c..00293a9 100644
--- 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 */
--
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