linux-kernel - Re: [PATCH RFC 0/2] ignore LBR-related MSRs

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Date:   Wed, 6 Dec 2017 10:06:48 -0500
From:   Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
To:     Jan Dakinevich <jan.dakinevich@...tuozzo.com>
Cc:     linux-kernel@...r.kernel.org,
        "Denis V . Lunev" <den@...tuozzo.com>,
        Roman Kagan <rkagan@...tuozzo.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        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>,
        "H. Peter Anvin" <hpa@...or.com>, x86@...nel.org,
        Paolo Bonzini <pbonzini@...hat.com>,
        Radim Krčmář <rkrcmar@...hat.com>,
        Andi Kleen <ak@...ux.intel.com>,
        Kan Liang <kan.liang@...el.com>,
        Colin King <colin.king@...onical.com>,
        Stephane Eranian <eranian@...gle.com>,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Jin Yao <yao.jin@...ux.intel.com>, kvm@...r.kernel.org
Subject: Re: [PATCH RFC 0/2] ignore LBR-related MSRs

On Wed, Dec 06, 2017 at 02:43:01PM +0300, Jan Dakinevich wrote:
> w2k16 essentials fails to boot if underlying hypervisor lacks of support for 
> LBR MSRs. To workaround the issue, it suggessted to ignore these MSRs (but not 
> all).

This is without any hyperv enablement? Meaning normal stock guest?

> 
> The information, which MSRs are supported for specific platform is taken from
> perf, it is the subject of the first patch. The second patch adds ignoring for
> these MSRs to pmu_intel code of KVM.
> 
> TODO: use MSR load/store areas to make full support of LBR debug.
> 
> Jan Dakinevich (2):
>   perf/x86/intel: make reusable LBR initialization code
>   KVM: x86/vPMU: ignore access to LBR-related MSRs
> 
>  arch/x86/events/core.c            |   8 +-
>  arch/x86/events/intel/core.c      |  59 +++------
>  arch/x86/events/intel/lbr.c       | 272 +++++++++++++++++++++++++-------------
>  arch/x86/events/perf_event.h      |  27 +---
>  arch/x86/include/asm/kvm_host.h   |   2 +
>  arch/x86/include/asm/perf_event.h |  11 ++
>  arch/x86/kvm/pmu_intel.c          |  33 +++++
>  7 files changed, 250 insertions(+), 162 deletions(-)
> 
> -- 
> 2.1.4
>