linux-kernel - Re: [PATCH v2 6/6] KVM: x86: Update vPMCs when retiring branch instructions

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Date:   Wed, 8 Dec 2021 20:40:16 -0800
From:   Jim Mattson <jmattson@...gle.com>
To:     Like Xu <like.xu.linux@...il.com>
Cc:     Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Joerg Roedel <joro@...tes.org>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 6/6] KVM: x86: Update vPMCs when retiring branch instructions

On Mon, Nov 29, 2021 at 11:42 PM Like Xu <like.xu.linux@...il.com> wrote:
>
> From: Jim Mattson <jmattson@...gle.com>
>
> When KVM retires a guest branch instruction through emulation,
> increment any vPMCs that are configured to monitor "branch
> instructions retired," and update the sample period of those counters
> so that they will overflow at the right time.
>
> Signed-off-by: Eric Hankland <ehankland@...gle.com>
> [jmattson:
>   - Split the code to increment "branch instructions retired" into a
>     separate commit.
>   - Moved/consolidated the calls to kvm_pmu_trigger_event() in the
>     emulation of VMLAUNCH/VMRESUME to accommodate the evolution of
>     that code.
> ]
> Fixes: f5132b01386b ("KVM: Expose a version 2 architectural PMU to a guests")
> Signed-off-by: Jim Mattson <jmattson@...gle.com>

I'm not sure if this is appropriate, but...

Reviewed-by: Jim Mattson <jmattson@...gle.com>