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From:   David Dai <davidai@google.com>
Date:   Mon, 31 Jul 2023 16:46:29 -0700
Message-ID: <CABN1KCJ0dfVBGdL0dd=ES2gmFJEgm89ArBsXWDC4hE4TZehk=Q@mail.gmail.com>
Subject: Re: [PATCH v3 2/2] cpufreq: add virtual-cpufreq driver
To:     Randy Dunlap <rdunlap@infradead.org>
Cc:     "Rafael J. Wysocki" <rafael@kernel.org>,
        Viresh Kumar <viresh.kumar@linaro.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Conor Dooley <conor+dt@kernel.org>,
        Sudeep Holla <sudeep.holla@arm.com>,
        Saravana Kannan <saravanak@google.com>,
        Quentin Perret <qperret@google.com>,
        Masami Hiramatsu <mhiramat@google.com>,
        Will Deacon <will@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        Marc Zyngier <maz@kernel.org>,
        Oliver Upton <oliver.upton@linux.dev>,
        Dietmar Eggemann <dietmar.eggemann@arm.com>,
        Pavan Kondeti <quic_pkondeti@quicinc.com>,
        Gupta Pankaj <pankaj.gupta@amd.com>,
        Mel Gorman <mgorman@suse.de>, kernel-team@android.com,
        linux-pm@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org
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Hi Randy,

Thanks for reviewing,

On Mon, Jul 31, 2023 at 3:02=E2=80=AFPM Randy Dunlap <rdunlap@infradead.org=
> wrote:
>
>
>
> On 7/31/23 10:46, David Dai wrote:
> > diff --git a/drivers/cpufreq/Kconfig b/drivers/cpufreq/Kconfig
> > index f429b9b37b76..3977ca796747 100644
> > --- a/drivers/cpufreq/Kconfig
> > +++ b/drivers/cpufreq/Kconfig
> > @@ -217,6 +217,21 @@ config CPUFREQ_DT
> >
> >         If in doubt, say N.
> >
> > +config CPUFREQ_VIRT
> > +        tristate "Virtual cpufreq driver"
> > +     depends on OF
> > +     select PM_OPP
> > +        help
>
> The 4 lines above should be indented with one tab (not 8 spaces).

Ok.

>
> > +       This adds a virtualized cpufreq driver for guest kernels that
> > +       read/writes to a MMIO region for a virtualized cpufreq device t=
o
>
>           reads/writes to an MMIO region

Will fix these, thanks!
David

>
> > +       communicate with the host. It sends frequency updates to the ho=
st
> > +       which gets used as a hint to schedule vCPU threads and select C=
PU
> > +       frequency. If a VM does not support a virtualized FIE such as A=
MUs,
> > +       it updates the frequency scaling factor by polling host CPU fre=
quency
> > +       to enable accurate Per-Entity Load Tracking for tasks running i=
n the guest.
> > +
> > +       If in doubt, say N.
>
> --
> ~Randy