linux-kernel - [PATCH v2 0/3] KVM: x86: Add AMD Guest PerfMonV2 PMU support

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Date:   Mon, 19 Sep 2022 17:34:50 +0800
From:   Like Xu <like.xu.linux@...il.com>
To:     Sean Christopherson <seanjc@...gle.com>,
        Paolo Bonzini <pbonzini@...hat.com>
Cc:     Jim Mattson <jmattson@...gle.com>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH v2 0/3] KVM: x86: Add AMD Guest PerfMonV2 PMU support

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.

The KVM part is based on the latest vPMU fixes patch set [1], while
the kvm-unit-test patch has been move to the preemptive test cases
effort [2] for testing leagcy AMD vPMU, which didn't exist before.

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

[1] https://lore.kernel.org/kvm/20220831085328.45489-1-likexu@tencent.com/
[2] https://lore.kernel.org/kvm/20220819110939.78013-1-likexu@tencent.com/

Previous:
https://lore.kernel.org/kvm/20220905123946.95223-1-likexu@tencent.com/

V1 -> V2 Changelog:
- The patch limiting the x86 GP counters is moved to specific patch set;
- MSR scope is bounded by pmu->nr_arch_gp_counters (Jim);
- Fn8000_0022_EBX can never report less than four counters \
  (or six, if Fn8000_0001_ECX[PerfCtrExtCore] is set); (Jim)
- Use "kvm_pmu_cap.version > 1" check instead of "guest perfmon_v2 bit";

Like Xu (2):
  KVM: x86/pmu: Make part of the Intel v2 PMU MSRs handling x86 generic
  KVM: x86/svm/pmu: Add AMD PerfMonV2 support

Sandipan Das (1):
  KVM: x86/cpuid: Add AMD CPUID ExtPerfMonAndDbg leaf 0x80000022

 arch/x86/include/asm/kvm-x86-pmu-ops.h |  1 -
 arch/x86/include/asm/kvm_host.h        |  1 +
 arch/x86/include/asm/perf_event.h      |  8 +++
 arch/x86/kvm/cpuid.c                   | 32 ++++++++++-
 arch/x86/kvm/pmu.c                     | 61 +++++++++++++++++++--
 arch/x86/kvm/pmu.h                     | 30 +++++++++-
 arch/x86/kvm/svm/pmu.c                 | 76 +++++++++++++++++++-------
 arch/x86/kvm/vmx/pmu_intel.c           | 58 +-------------------
 arch/x86/kvm/x86.c                     | 14 ++++-
 9 files changed, 193 insertions(+), 88 deletions(-)

-- 
2.37.3