linux-kernel - Re: [PATCH v3 0/7] x86/pmu: Corner cases fixes and optimization

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Message-ID: <Yyzh3VD+Gji8t9OO@google.com>
Date:   Thu, 22 Sep 2022 22:29:49 +0000
From:   Sean Christopherson <seanjc@...gle.com>
To:     Like Xu <like.xu.linux@...il.com>
Cc:     Paolo Bonzini <pbonzini@...hat.com>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 0/7] x86/pmu: Corner cases fixes and optimization

On Wed, Aug 31, 2022, Like Xu wrote:
> Like Xu (7):
>   KVM: x86/pmu: Avoid setting BIT_ULL(-1) to pmu->host_cross_mapped_mask
>   KVM: x86/pmu: Don't generate PEBS records for emulated instructions
>   KVM: x86/pmu: Avoid using PEBS perf_events for normal counters
>   KVM: x86/pmu: Defer reprogram_counter() to kvm_pmu_handle_event()
>   KVM: x86/pmu: Defer counter emulated overflow via pmc->prev_counter
>   KVM: x86/svm/pmu: Direct access pmu->gp_counter[] to implement
>     amd_*_to_pmc()
>   KVM: x86/svm/pmu: Rewrite get_gp_pmc_amd() for more counters
>     scalability

With a few tweaks (will respond to individual patches), pushed everything except
the "Defer" patches to to branch `for_paolo/6.1` at:

    https://github.com/sean-jc/linux.git

Unless you hear otherwise, it will make its way to kvm/queue "soon".

Regarding the "defer" patches, your patches are ok (with one or two tweaks), but
there are existing bugs that I believe will interact poorly with using reprogram_pmi
more agressively.  Nothing major, but I'd prefer to get everything squared away
before merging, and definitely want your input on my proposed fixes.  I'll post
the patches shortly.