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From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Gleb Natapov <gleb@minantech.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
        Dirk Brandewie <dirk.brandewie@gmail.com>,
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        "Richard W.M. Jones" <rjones@redhat.com>
Subject: Re: intel_pstate divide error with v3.13-rc4-256-gb7000ad
Date: Sat, 04 Jan 2014 22:38:33 +0100
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On Saturday, January 04, 2014 07:48:13 PM Gleb Natapov wrote:
> On Sat, Jan 04, 2014 at 06:38:59PM +0100, Paolo Bonzini wrote:
> > Il 04/01/2014 15:38, Rafael J. Wysocki ha scritto:
> > > Well, it's just a sanity check and it makes the problem go away for the reporter.
> > > 
> > >> > Your patch is welcome but perhaps it should have a WARN_ON too.
> > > It has been pulled in already, so the WARN_ON() can only be added via a separate
> > > patch now.  Would you like to prepare that patch?
> > 
> > Yes, I'll add it together with the CPUID check.  I'll send the patch so
> > that it can get into 3.14.
> > 
> CPUID check, while correct, will sweep the problem under the rug. Current
> Linux logic should detect non working pstate in KVM. We should look into
> why this is not happening for nested.

I agree.  It's better not to use CPUID for that in my opinion.

Thanks!

-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.