[PATCH v3 0/8] KVM: x86: Add AMD Guest PerfMonV2 PMU support

Like Xu
2022-11-11T10:27:43Z

Starting with Zen4, core PMU on AMD platforms such as Genoa and
Ryzen-7000 will support PerfMonV2, and it is also compatible with
legacy PERFCTR_CORE behavior and msr addresses.

If you don't have access to the hardware specification, the commits
d6d0c7f681fd..7685665c390d for host perf can also bring a quick
overview. Its main change is the addition of three msr's equivalent
to Intel V2, namely global_ctrl, global_status, global_status_clear.

It is worth noting that this feature is very attractive for reducing the
overhead of PMU virtualization, since multiple msr accesses to multiple
counters will be replaced by a single access to the global register,
plus more accuracy gain when multiple guest counters are used.

All related testcases are passed on a Genoa box.
Please feel free to run more tests, add more or share comments.

Previous:
https://lore.kernel.org/kvm/20220919093453.71737-1-likexu@tencent.com/

V2 -> V3 Changelog:
- Renme pmc_is_enabled(); (Jim)
- Move the reprogram_counters() changes as a separate patch; (Jim)
- Refactoring to align with other set_msr() helper; (Sean)
- Fix the issue if userspace wants to expose v1 for whatever reason; (Sean)
- Add the feature flag X86_FEATURE_AMD_PMU_V2; (Sean)
- Check enable_pmu for intel 0xa as well; (Sean)
- Limit AMD pmu's KVM support to version 2 as well;
- Other nit changes around C code taste; (Sean)

Like Xu (7):
KVM: x86/pmu: Rename pmc_is_enabled() to pmc_is_globally_enabled()
KVM: x86/pmu: Rewrite reprogram_counters() to improve performance
KVM: x86/pmu: Make part of the Intel v2 PMU MSRs handling x86 generic
KVM: x86/cpuid: Add X86_FEATURE_AMD_PMU_V2 as a KVM-only leaf entry
KVM: x86/svm/pmu: Add AMD PerfMonV2 support
KVM: x86/cpuid: Add AMD CPUID ExtPerfMonAndDbg leaf 0x80000022
KVM: x86/cpuid: Use fast return for cpuid "0xa" leaf when !enable_pmu

Sean Christopherson (1):
KVM: VMX: Refactor intel_pmu_set_msr() to align with other set_msr()
helpers

arch/x86/include/asm/kvm-x86-pmu-ops.h | 1 -
arch/x86/include/asm/kvm_host.h | 1 +
arch/x86/kvm/cpuid.c | 32 ++++++-
arch/x86/kvm/pmu.c | 65 +++++++++++++--
arch/x86/kvm/pmu.h | 28 ++++++-
arch/x86/kvm/reverse_cpuid.h | 10 +++
arch/x86/kvm/svm/pmu.c | 73 +++++++++++-----
arch/x86/kvm/svm/svm.c | 11 ++-
arch/x86/kvm/vmx/pmu_intel.c | 111 +++++++------------------
arch/x86/kvm/x86.c | 14 +++-
10 files changed, 228 insertions(+), 118 deletions(-)

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2.38.1