linux-kernel - Re: [PATCH v2 3/4] Add support for AMD Core Perf Extension in guest

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Message-ID: <20171116172520.4lgdvpcdxuxenxc7@pd.tnic>
Date:   Thu, 16 Nov 2017 18:25:20 +0100
From:   Borislav Petkov <bp@...e.de>
To:     "Natarajan, Janakarajan" <Janakarajan.Natarajan@....com>
Cc:     kvm@...r.kernel.org, x86@...nel.org, linux-kernel@...r.kernel.org,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "H . Peter Anvin" <hpa@...or.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Radim Krcmar <rkrcmar@...hat.com>,
        Len Brown <len.brown@...el.com>, Kyle Huey <me@...ehuey.com>,
        Kan Liang <Kan.liang@...el.com>,
        Grzegorz Andrejczuk <grzegorz.andrejczuk@...el.com>,
        Tom Lendacky <thomas.lendacky@....com>,
        Tony Luck <tony.luck@...el.com>
Subject: Re: [PATCH v2 3/4] Add support for AMD Core Perf Extension in guest

On Thu, Nov 16, 2017 at 11:13:47AM -0600, Natarajan, Janakarajan wrote:
> On 11/15/2017 1:07 PM, Borislav Petkov wrote:
> > On Wed, Nov 15, 2017 at 01:04:03PM -0600, Natarajan, Janakarajan wrote:
> > > So, when the amd_pmu_init is called, a query to guest_cpuid_family() gives a
> > > value of -1.
> > And that is because...? And it can be fixed to give the proper guest family I
> > presume ...?
> 
> Qemu initially creates a vcpu with KVM_CREATE_VCPU which in kvm initializes
> the pmu. Later on
> the cpuid is set using KVM_SET_CPUID2 which sets all the cpuid entries in
> kvm and the pmu refresh is called.

That doesn't answer my questions above.

-- 
Regards/Gruss,
    Boris.

SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
--