Changes since v3:
- Use cpuid_entry_override() for the newly introduces CPUID_8000_0007_EDX
leaf in __do_cpuid_func(). [Sean]
- Add comments and reshuffle check in kvm_hv_invtsc_suppressed() [Sean]
Original description:
Normally, genuine Hyper-V doesn't expose architectural invariant TSC
(CPUID.80000007H:EDX[8]) to its guests by default. A special PV MSR
(HV_X64_MSR_TSC_INVARIANT_CONTROL, 0x40000118) and corresponding CPUID
feature bit (CPUID.0x40000003.EAX[15]) were introduced. When bit 0 of the
PV MSR is set, invariant TSC bit starts to show up in CPUID. When the
feature is exposed to Hyper-V guests, reenlightenment becomes unneeded.
Note: strictly speaking, KVM doesn't have to have the feature as exposing
raw invariant TSC bit (CPUID.80000007H:EDX[8]) also seems to work for
modern Windows versions. The feature is, however, tiny and straitforward
and gives additional flexibility so why not.
Vitaly Kuznetsov (6):
x86/hyperv: Add HV_INVARIANT_TSC_EXPOSED define
KVM: x86: Introduce CPUID_8000_0007_EDX 'scattered' leaf
KVM: x86: Hyper-V invariant TSC control
KVM: selftests: Rename 'msr->availble' to 'msr->fault_exepected' in
hyperv_features test
KVM: selftests: Convert hyperv_features test to using
KVM_X86_CPU_FEATURE()
KVM: selftests: Test Hyper-V invariant TSC control
arch/x86/include/asm/hyperv-tlfs.h | 3 +
arch/x86/include/asm/kvm_host.h | 1 +
arch/x86/kernel/cpu/mshyperv.c | 2 +-
arch/x86/kvm/cpuid.c | 11 +-
arch/x86/kvm/hyperv.c | 19 ++
arch/x86/kvm/hyperv.h | 27 +++
arch/x86/kvm/reverse_cpuid.h | 9 +-
arch/x86/kvm/x86.c | 4 +-
.../selftests/kvm/include/x86_64/hyperv.h | 144 ++++++++----
.../selftests/kvm/include/x86_64/processor.h | 1 +
.../selftests/kvm/x86_64/hyperv_features.c | 212 +++++++++++-------
11 files changed, 295 insertions(+), 138 deletions(-)
--
2.37.3
