linux-kernel - Re: GPF in intel_pmu_lbr_reset() with qemu -cpu host

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Message-ID: <20140322003056.GQ22728@two.firstfloor.org>
Date:	Sat, 22 Mar 2014 01:30:56 +0100
From:	Andi Kleen <andi@...stfloor.org>
To:	"H. Peter Anvin" <hpa@...or.com>
Cc:	Andi Kleen <andi@...stfloor.org>, Peter Wu <peter@...ensteyn.nl>,
	Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...nel.org>, linux-kernel@...r.kernel.org
Subject: Re: GPF in intel_pmu_lbr_reset() with qemu -cpu host

On Fri, Mar 21, 2014 at 05:26:17PM -0700, H. Peter Anvin wrote:
> On 03/21/2014 05:22 PM, Andi Kleen wrote:
> >> Actually, Ingo, Borislav and I have been discussing making rdmsr_safe()
> >> more of the default, especially for things like this where the error
> >> handling is obvious (doesn't work?  Disable the PMU.)
> > 
> > That would be completely wrong. KVM has a full architectural perfmon PMU,
> > just no model specific extensions like LBR.
> > 
> 
> s/PMU/PMU extension in question/

%  grep -r 'rdmsr' arch/x86/*  | grep -v safe | wc -l
285

I assume it'll keep you all busy for a while.

[compared to a likely one liner in KVM]

-Andi
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