Changes since v1:
- Drop "KVM: selftests: Fix wrmsr_safe()" patch as it is already merged.
- Add 'KVM: selftests: Rename 'msr->availble' to 'msr->should_not_gp' in
hyperv_features test' patch [Max]
- Rebase selftest to the current API.
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 (3):
KVM: x86: Hyper-V invariant TSC control
KVM: selftests: Rename 'msr->availble' to 'msr->should_not_gp' in
hyperv_features test
KVM: selftests: Test Hyper-V invariant TSC control
arch/x86/include/asm/kvm_host.h | 1 +
arch/x86/kvm/cpuid.c | 7 +
arch/x86/kvm/hyperv.c | 19 +++
arch/x86/kvm/hyperv.h | 15 ++
arch/x86/kvm/x86.c | 4 +-
.../selftests/kvm/x86_64/hyperv_features.c | 159 +++++++++++++-----
6 files changed, 158 insertions(+), 47 deletions(-)
--
2.37.2
