Hyper-V may expose a HV_X64_MSR_GUEST_IDLE MSR. We can read HYPERV_CPUID_FEATURES eax to check it. Read this MSR can trigger the guest's transition to the idle power state which can be exited by an IPI even if IF flag is disabled.
Cc: "K. Y. Srinivasan" <k...@microsoft.com> Cc: Haiyang Zhang <haiya...@microsoft.com> Cc: Stephen Hemminger <sthem...@microsoft.com> Signed-off-by: Yi Sun <yi.y....@linux.intel.com> --- arch/x86/include/asm/hyperv-tlfs.h | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/arch/x86/include/asm/hyperv-tlfs.h b/arch/x86/include/asm/hyperv-tlfs.h index e977b6b..2a2fa17 100644 --- a/arch/x86/include/asm/hyperv-tlfs.h +++ b/arch/x86/include/asm/hyperv-tlfs.h @@ -38,6 +38,8 @@ #define HV_MSR_TIME_REF_COUNT_AVAILABLE (1 << 1) /* Partition reference TSC MSR is available */ #define HV_MSR_REFERENCE_TSC_AVAILABLE (1 << 9) +/* Partition Guest IDLE MSR is available */ +#define HV_X64_MSR_GUEST_IDLE_AVAILABLE (1 << 10) /* A partition's reference time stamp counter (TSC) page */ #define HV_X64_MSR_REFERENCE_TSC 0x40000021 @@ -246,6 +248,9 @@ #define HV_X64_MSR_STIMER3_CONFIG 0x400000B6 #define HV_X64_MSR_STIMER3_COUNT 0x400000B7 +/* Hyper-V guest idle MSR */ +#define HV_X64_MSR_GUEST_IDLE 0x400000F0 + /* Hyper-V guest crash notification MSR's */ #define HV_X64_MSR_CRASH_P0 0x40000100 #define HV_X64_MSR_CRASH_P1 0x40000101 -- 1.9.1
