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

From: Jim Mattson
Date: Wed Dec 08 2021 - 23:40:32 EST


On Mon, Nov 29, 2021 at 11:42 PM Like Xu <like.xu.linux@xxxxxxxxx> wrote:
>
> From: Jim Mattson <jmattson@xxxxxxxxxx>
>
> 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@xxxxxxxxxx>
> [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@xxxxxxxxxx>

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

Reviewed-by: Jim Mattson <jmattson@xxxxxxxxxx>