Subject: Re: [V2 PATCH 0/6] x86, NMI: give NMI handler a face-lift
From: Peter Zijlstra <peterz@infradead.org>
To: Jason Wessel <jason.wessel@windriver.com>
Cc: Don Zickus <dzickus@redhat.com>, Ingo Molnar <mingo@elte.hu>,
        Robert Richter <robert.richter@amd.com>, ying.huang@intel.com,
        Andi Kleen <andi@firstfloor.org>, LKML <linux-kernel@vger.kernel.org>,
        Frederic Weisbecker <fweisbec@gmail.com>
In-Reply-To: <4CE583D0.8050407@windriver.com>
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	 <20101118080516.GJ32621@elte.hu> <4CE52048.5080802@windriver.com>
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Date: Thu, 18 Nov 2010 21:04:20 +0100
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On Thu, 2010-11-18 at 13:51 -0600, Jason Wessel wrote:
> I highly doubt we want to disable perf.   I would rather use the source
> and fix the nmi emulation in KVM/Qemu after we hear back the results
> from Cyril because it sounds as if the problem is nearly bottomed out.

Problem is that p6/p4/amd don't have cpuid bits telling us if there is a
PMU (virt should clear those if it doesn't emulate one).

I guess the safest course is to write a pmu msr and see if that faults,
if it does, disable the thing.


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