Re: [Patch v3 0/6] Perf kvm commands bug fix

Arnaldo Carvalho de Melo
2025-10-02T18:30:58Z

On Fri, Sep 19, 2025 at 10:16:53AM +0800, Dapeng Mi wrote:
> This patch-set fixes perf kvm commands issues, like missed memory
> allocation check/free, out of range memory access and especially the
> issue that fails to sample guest with "perf kvm record/top" commands on
> Intel platforms.
>
> Since the change "KVM: x86/pmu: Add basic support to enable guest PEBS
> via DS"[1] starts, host loses the capability to sample guest with PEBS
> since all PEBS related MSRs are switched to guest value after vm-entry,
> like IA32_DS_AREA MSR is switched to guest GVA at vm-entry. This leads
> to PEBS events can't be used to sample guest by host, otherwise no guest
> PEBS records can be really sampled. The patches 5-6/6 fix this issue by
> using "cycles" event instead of PEBS event "cycles:P" to sample guest on
> Intel platforms.
>
> Changes:
> v2 -> v3:
> * Correct the fixes tag in patch 5-6/6.
> * Add "acked-by" tag from Namhyung.
>

Thanks, applied to perf-tools-next,

- Arnaldo