From mboxrd@z Thu Jan  1 00:00:00 1970
From: Gleb Natapov <gleb@redhat.com>
Subject: Re: kernel 3.10.1 - "NMI received for unknown reason"
Date: Sun, 25 Aug 2013 14:45:29 +0300
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To: Stefan Pietsch <stefan.pietsch@lsexperts.de>
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On Fri, Aug 09, 2013 at 09:14:13PM +0200, Stefan Pietsch wrote:
> On 04.08.2013 14:44, Gleb Natapov wrote:
> > On Fri, Aug 02, 2013 at 08:24:38AM +0200, Stefan Pietsch wrote:
> >> On 31.07.2013 11:20, Gleb Natapov wrote:
> >>> On Wed, Jul 31, 2013 at 11:10:01AM +0200, Stefan Pietsch wrote:
> >>>> On 30.07.2013 07:31, Gleb Natapov wrote:
> >>>>
> >>>>> What happen if you run perf on your host (perf record -a)?
> >>>>> Do you see same NMI messages?
> >>>>
> >>>> It seems that "perf record -a" triggers some delayed NMI messages.
> >>>> They appear about 20 or 30 minutes after the command. This seems strange.
> >>> Definitely strange. KVM guest is not running in parallel, correct? 20, 30
> >>> minutes after perf stopped running or it is running all of the time?
> >>
> >> No, the KVM guest ist not running in parallel. But I'm not able to
> >> clearly reproduce the NMI messages with "perf record".
> >> I start "perf record -a" and after some minutes I stop the recording.
> >>
> >> After that it seems NMI messages appear within a random period of time.
> >> So, I cannot tell what triggers the messages.
> > When you run KVM with coreduo cpu model it emulates PMU which basically
> > make is perf front end. If you can reproduce the messages with perf too
> > it probably means that the problem is not in the KVM itself. If you
> > disabled NMI watchdog in the guest the messages may go away.
> > Can you send your guest's dmesg when you boot it with coreduo mode?
> 
> 
> The NMI messages appear in the host only. The guest runs as usual.
> 
> 
I understand that. But enabling guest nmi watchdog is what makes KVM to
use perf subsystem and likely causes this host messages. Try do disable
nmi watchdog in a guest and see what happens.

--
			Gleb.