linux-kernel - Re: [PATCH] perf/x86: KVM: Disable vPMU support on hybrid CPUs (host PMUs)

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Message-ID: <67facb87-f835-abcd-3d1b-527531b26e52@linux.intel.com>
Date:   Mon, 23 Jan 2023 17:04:33 -0800
From:   Andi Kleen <ak@...ux.intel.com>
To:     "Liang, Kan" <kan.liang@...ux.intel.com>,
        Sean Christopherson <seanjc@...gle.com>
Cc:     Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Borislav Petkov <bp@...en8.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...nel.org>,
        Namhyung Kim <namhyung@...nel.org>,
        "H. Peter Anvin" <hpa@...or.com>, linux-perf-users@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Jianfeng Gao <jianfeng.gao@...el.com>,
        Andrew Cooper <Andrew.Cooper3@...rix.com>
Subject: Re: [PATCH] perf/x86: KVM: Disable vPMU support on hybrid CPUs (host
 PMUs)


> If I understand correct, the workaround in KVM is to add a white/black
> list to filter the events. I think we can do the same thing for the
> hybrid machine for now.
> https://lore.kernel.org/lkml/CAOyeoRUUK+T_71J=+zcToyL93LkpARpsuWSfZS7jbJq=wd1rQg@mail.gmail.com/


This will make everyone who actually wants to use the PMU sad.

It's reasonable if the vCPUs are not bound, but if they are bound it 
would be better to expose it with a suitable CPUID for the types.


-Andi