linux-kernel - Re: [PATCH] perf/x86: Apply more accurate check on hypervisor platform

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Date:   Thu, 25 Jul 2019 09:46:31 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Zhenzhong Duan <zhenzhong.duan@...cle.com>
Cc:     linux-kernel@...r.kernel.org, x86@...nel.org,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...hat.com>,
        Namhyung Kim <namhyung@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Juergen Gross <jgross@...e.com>,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>
Subject: Re: [PATCH] perf/x86: Apply more accurate check on hypervisor
 platform

On Thu, Jul 25, 2019 at 10:39:26AM +0800, Zhenzhong Duan wrote:
> check_msr is used to fix a bug report in guest where KVM doesn't support
> LBR MSR and cause #GP.
> 
> The msr check is bypassed on real HW to workaround a false failure,
> see commit d0e1a507bdc7 ("perf/x86/intel: Disable check_msr for real HW")
> 
> When running a guest with CONFIG_HYPERVISOR_GUEST not set or "nopv"
> enabled, current check isn't enough and #GP could trigger.
> 
> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@...cle.com>
> Cc: Peter Zijlstra <peterz@...radead.org>
> Cc: Arnaldo Carvalho de Melo <acme@...nel.org>
> Cc: Alexander Shishkin <alexander.shishkin@...ux.intel.com>
> Cc: Jiri Olsa <jolsa@...hat.com>
> Cc: Namhyung Kim <namhyung@...nel.org>
> Cc: Thomas Gleixner <tglx@...utronix.de>
> Cc: Ingo Molnar <mingo@...hat.com>
> Cc: Borislav Petkov <bp@...en8.de>
> Cc: Juergen Gross <jgross@...e.com>
> Cc: Boris Ostrovsky <boris.ostrovsky@...cle.com>

Thanks!