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

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Message-ID: <aN7E3wnC4tZ8jenN@x1>
Date: Thu, 2 Oct 2025 15:30:55 -0300
From: Arnaldo Carvalho de Melo <acme@...nel.org>
To: Dapeng Mi <dapeng1.mi@...ux.intel.com>
Cc: Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>,
	Namhyung Kim <namhyung@...nel.org>, Ian Rogers <irogers@...gle.com>,
	Adrian Hunter <adrian.hunter@...el.com>,
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
	Kan Liang <kan.liang@...ux.intel.com>,
	linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org,
	Dapeng Mi <dapeng1.mi@...el.com>
Subject: Re: [Patch v3 0/6] Perf kvm commands bug fix

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