From: Sean Christopherson <seanjc@google.com>
To: Like Xu <like.xu.linux@gmail.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 10/12] KVM: x86/cpuid: Add X86_FEATURE_PERFMON_V2 as a scattered flag
Date: Thu, 6 Apr 2023 17:41:26 -0700 [thread overview]
Message-ID: <ZC9mtqxmqKAoelNO@google.com> (raw)
In-Reply-To: <20230214050757.9623-11-likexu@tencent.com>
This shortlog is flat out wrong. This patch does not add X86_FEATURE_PERFMON_V2,
it adds a KVM-only leaf to redirect X86_FEATURE_PERFMON_V2 to its architectural
location when KVM queries the leaf, e.g. via guest_cpuid_has().
On Tue, Feb 14, 2023, Like Xu wrote:
> From: Like Xu <likexu@tencent.com>
>
> Considering that the core kernel may also want to know this flag, to avoid
Please write changelogs so that they do not depend on the shortlog for context.
I know the tip maintainers in particular like to make the changelog a continuation
of the shortlog, but I find it really annoying, especially when reviewing in mutt,
e.g. as I'm typing this, I don't even have the shortlog visible.
In the vast majority of cases, being more explicit rarely adds more than a few
chars, e.g. you'll save more by reducing the fluff in this changelog.
> confusion this needs to be a scattered flag rather than a pure KVM flag so
> that KVM can redirect it to the hardware-defined bit position, which is the
> role of __feature_translate() and KVM_X86_FEATURE_PERFMON_V2.
Like the shortlog, the changelog is best misleading, X86_FEATURE_PERFMON_V2 is
already a scattered flag.
Define a KVM-only leaf for AMD's PerfMonV2 feature flag to redirect the
kernel's scattered version to its architectural location, e.g. so that
KVM can query guest support via guest_cpuid_has().
next prev parent reply other threads:[~2023-04-07 0:41 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-14 5:07 [PATCH v4 00/12] KVM: x86: Add AMD Guest PerfMonV2 PMU support Like Xu
2023-02-14 5:07 ` [PATCH v4 01/12] KVM: x86/pmu: Rename pmc_is_enabled() to pmc_is_globally_enabled() Like Xu
2023-02-14 5:07 ` [PATCH v4 02/12] KVM: VMX: Refactor intel_pmu_set_msr() to align with other set_msr() helpers Like Xu
2023-02-16 21:13 ` Sean Christopherson
2023-02-21 8:44 ` Like Xu
2023-03-23 7:43 ` Like Xu
2023-03-23 14:28 ` Sean Christopherson
2023-02-14 5:07 ` [PATCH v4 03/12] KVM: x86/pmu: Rewrite reprogram_counters() to improve performance Like Xu
2023-02-14 5:07 ` [PATCH v4 04/12] KVM: x86/pmu: Expose reprogram_counters() in pmu.h Like Xu
2023-02-14 5:07 ` [PATCH v4 05/12] KVM: x86/pmu: Error when user sets the GLOBAL_STATUS reserved bits Like Xu
2023-04-06 23:45 ` Sean Christopherson
2023-04-07 5:08 ` Like Xu
2023-04-07 15:43 ` Sean Christopherson
2023-02-14 5:07 ` [PATCH v4 06/12] KVM: x86/pmu: Make part of the Intel v2 PMU MSRs handling x86 generic Like Xu
2023-04-06 23:57 ` Sean Christopherson
2023-04-07 1:39 ` Sean Christopherson
2023-02-14 5:07 ` [PATCH v4 07/12] KVM: x86/cpuid: Use fast return for cpuid "0xa" leaf when !enable_pmu Like Xu
2023-04-06 23:59 ` Sean Christopherson
2023-02-14 5:07 ` [PATCH v4 08/12] KVM: x86/pmu: Disable vPMU if the minimum num of counters isn't met Like Xu
2023-04-07 0:06 ` Sean Christopherson
2023-04-07 0:23 ` Sean Christopherson
2023-02-14 5:07 ` [PATCH v4 09/12] KVM: x86/pmu: Forget PERFCTR_CORE if the min " Like Xu
2023-04-07 0:32 ` Sean Christopherson
2023-02-14 5:07 ` [PATCH v4 10/12] KVM: x86/cpuid: Add X86_FEATURE_PERFMON_V2 as a scattered flag Like Xu
2023-04-07 0:41 ` Sean Christopherson [this message]
2023-02-14 5:07 ` [PATCH v4 11/12] KVM: x86/svm/pmu: Add AMD PerfMonV2 support Like Xu
2023-04-07 1:35 ` Sean Christopherson
2023-04-07 7:08 ` Like Xu
2023-04-07 14:44 ` Sean Christopherson
2023-04-10 11:34 ` Like Xu
2023-02-14 5:07 ` [PATCH v4 12/12] KVM: x86/cpuid: Add AMD CPUID ExtPerfMonAndDbg leaf 0x80000022 Like Xu
2023-04-07 1:50 ` Sean Christopherson
2023-04-07 7:19 ` Like Xu
2023-04-07 2:02 ` [PATCH v4 00/12] KVM: x86: Add AMD Guest PerfMonV2 PMU support Sean Christopherson
2023-04-07 7:28 ` Like Xu
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