Re: [PATCH v2 2/3] KVM: x86/svm/pmu: Add AMD PerfMonV2 support

[Jim Mattson]

On Mon, Sep 19, 2022 at 2:35 AM Like Xu <like.xu.linux@xxxxxxxxx> wrote:
>
> From: Like Xu <likexu@xxxxxxxxxxx>
>
> If AMD Performance Monitoring Version 2 (PerfMonV2) is detected
> by the guest, it can use a new scheme to manage the Core PMCs using
> the new global control and status registers.
>
> In addition to benefiting from the PerfMonV2 functionality in the same
> way as the host (higher precision), the guest also can reduce the number
> of vm-exits by lowering the total number of MSRs accesses.
>
> In terms of implementation details, amd_is_valid_msr() is resurrected
> since three newly added MSRs could not be mapped to one vPMC.
> The possibility of emulating PerfMonV2 on the mainframe has also
> been eliminated for reasons of precision.
>
> Co-developed-by: Sandipan Das <sandipan.das@xxxxxxx>
> Signed-off-by: Sandipan Das <sandipan.das@xxxxxxx>
> Signed-off-by: Like Xu <likexu@xxxxxxxxxxx>
Reviewed-by: Jim Mattson <jmattson@xxxxxxxxxx>