Commits
Grzegorz Andrejczuk committed ae47eda905e
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>