Allow guest reads of IA32_APERF and IA32_MPERF, so that it can
determine the effective frequency multiplier for the physical LPU.
Commit b51700632e0e ("KVM: X86: Provide a capability to disable cstate
msr read intercepts") allowed the userspace VMM to grant a guest read
access to four core C-state residency MSRs. Do the same for IA32_APERF
and IA32_MPERF.
While this isn't sufficient to claim support for
CPUID.6:ECX.APERFMPERF[bit 0], it may suffice in a sufficiently
restricted environment (i.e. vCPUs pinned to LPUs, no TSC multiplier,
and no suspend/resume).
v1 -> v2: Add {IA32_APERF,IA32_MPERF} to vmx_possible_passthrough_msrs[]
v2 -> v3: Add a selftest
Jim Mattson (2):
KVM: x86: Provide a capability to disable APERF/MPERF read intercepts
KVM: selftests: Test behavior of KVM_X86_DISABLE_EXITS_APERFMPERF
Documentation/virt/kvm/api.rst | 1 +
arch/x86/include/asm/kvm_host.h | 1 +
arch/x86/kvm/svm/svm.c | 7 +
arch/x86/kvm/svm/svm.h | 2 +-
arch/x86/kvm/vmx/vmx.c | 6 +
arch/x86/kvm/vmx/vmx.h | 2 +-
arch/x86/kvm/x86.c | 8 +-
arch/x86/kvm/x86.h | 5 +
include/uapi/linux/kvm.h | 1 +
tools/include/uapi/linux/kvm.h | 4 +-
tools/testing/selftests/kvm/Makefile.kvm | 1 +
.../selftests/kvm/x86/aperfmperf_test.c | 162 ++++++++++++++++++
12 files changed, 196 insertions(+), 4 deletions(-)
create mode 100644 tools/testing/selftests/kvm/x86/aperfmperf_test.c
--
2.49.0.395.g12beb8f557-goog
