linux-kernel - Re: [PATCH v5 0/3] Support Perf Extension on AMD KVM guests

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Message-ID: <20180306210231.GC12128@flask>
Date:   Tue, 6 Mar 2018 22:02:31 +0100
From:   Radim Krcmar <rkrcmar@...hat.com>
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>,
        Len Brown <len.brown@...el.com>, Borislav Petkov <bp@...e.de>,
        Kyle Huey <me@...ehuey.com>,
        Tom Lendacky <thomas.lendacky@....com>
Subject: Re: [PATCH v5 0/3] Support Perf Extension on AMD KVM guests

2018-02-16 13:26-0600, Natarajan, Janakarajan:
> On 2/5/2018 1:24 PM, Janakarajan Natarajan wrote:
> > This patchset adds support for Perf Extension on AMD KVM guests.
> > 
> > When perf runs on a guest with family = 15h || 17h, the MSRs that are
> > accessed, when the Perf Extension flag is made available, differ from
> > the existing K7 MSRs. The accesses are to the AMD Core Performance
> > Extension counters which provide 2 extra counters and new MSRs for both
> > the event select and counter registers.
> > 
> > Since the new event select and counter MSRs are interleaved and K7 MSRs
> > are contiguous, the logic to map them to the gp_counters[] is changed.
> > 
> > This patchset has been tested with Family 17h and Opteron G1 guests.
> > 
> > v1->v2:
> > * Rearranged MSR #defines based on Boris's suggestion.
> > 
> > v2->v3:
> > * Changed the logic of mapping MSR to gp_counters[] index based on
> >    Boris's feedback.
> > * Removed use of family checks based on Radim's feedback.
> > * Removed KVM bugfix patch since it is already applied.
> > 
> > v3->v4:
> > * Rebased to latest KVM tree.
> > 
> > v4->v5:
> > * Removed conditional check when exposing Perf Extension flag to
> >    guests based on Radim's feedback.
> > 
> > Janakarajan Natarajan (3):
> >    x86/msr: Add AMD Core Perf Extension MSRs
> >    x86/kvm: Add support for AMD Core Perf Extension in guest
> >    x86/kvm: Expose AMD Core Perf Extension flag to guests
> 
> Are there any concerns regarding this patchset?

No, looks ok!

I have squashed the last patch, added a sanity BUILD_BUG_ON and applied
to kvm/queue (until we're sure that [1/3] goes through the kvm tree),
thanks.