[PATCH v4 00/12] KVM: x86: Add AMD Guest PerfMonV2 PMU support

Like Xu
2023-02-14T05:08:22Z

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.

Patch 0001-0009 could be applied earlier, which may help reduce
the burden on industrious reviewers.

Base: kvm-x86/pmu
Previous: 20221111102645.82001-1-likexu@tencent.com

V3 -> V4 Changelog:
- Compilability of each patch is retained; (Sean)
- Apply "if (!diff)" style and use the atomic set_bit(); (Sean)
- First optimize the helper, then expose it in pmu.h; (Sean)
- Just use scattered X86_FEATURE_PERFMON_V2; (Sean)
- Drop use of kvm_cpu_cap_has() when refresh; (Sean)
- Use tweaked kvm_pmu_cap.num_counters_gp; (Sean)
- Sanity check the number of counters enumerated by perf; (Sean)
- Apply an if-elif-else sequence for number of counters; (Sean)
- Refine commits messages to provide hidden information; (Sean)
- Apply kvm_cpu_cap_check_and_set() when enable_pmu; (Sean)
- Fix a coner case when user sets GLOBAL_STATUS reserved bits;
- For AMD GLOBAL_STATUS, writes are ignored as host does;
- For AMD GLOBAL_CTL, none #GP on writes as host does;
- For AMD GLOBAL_STATUS_CLR, none #GP on writes as host does;

Like Xu (11):
KVM: x86/pmu: Rename pmc_is_enabled() to pmc_is_globally_enabled()
KVM: x86/pmu: Rewrite reprogram_counters() to improve performance
KVM: x86/pmu: Expose reprogram_counters() in pmu.h
KVM: x86/pmu: Error when user sets the GLOBAL_STATUS reserved bits
KVM: x86/pmu: Make part of the Intel v2 PMU MSRs handling x86 generic
KVM: x86/cpuid: Use fast return for cpuid "0xa" leaf when !enable_pmu
KVM: x86/pmu: Disable vPMU if the minimum num of counters isn't met
KVM: x86/pmu: Forget PERFCTR_CORE if the min num of counters isn't met
KVM: x86/cpuid: Add X86_FEATURE_PERFMON_V2 as a scattered flag
KVM: x86/svm/pmu: Add AMD PerfMonV2 support
KVM: x86/cpuid: Add AMD CPUID ExtPerfMonAndDbg leaf 0x80000022

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/kvm/cpuid.c | 26 +++++-
arch/x86/kvm/pmu.c | 69 +++++++++++++--
arch/x86/kvm/pmu.h | 35 +++++++-
arch/x86/kvm/reverse_cpuid.h | 7 ++
arch/x86/kvm/svm/pmu.c | 62 +++++++++-----
arch/x86/kvm/svm/svm.c | 17 +++-
arch/x86/kvm/vmx/pmu_intel.c | 114 +++++++------------------
arch/x86/kvm/x86.c | 10 +++
9 files changed, 223 insertions(+), 118 deletions(-)

--
2.39.1