Re: perf with precise attribute kills all KVM based VMs

From: Gleb Natapov
Date: Mon Jul 09 2012 - 10:57:14 EST


On Mon, Jul 09, 2012 at 05:54:42PM +0300, Gleb Natapov wrote:
> On Mon, Jul 09, 2012 at 05:51:29PM +0300, Avi Kivity wrote:
> > On 07/09/2012 05:49 PM, Peter Zijlstra wrote:
> > > On Mon, 2012-07-09 at 08:47 -0600, David Ahern wrote:
> > >>
> > >> I found this testing changes to perf-kvm, but found the problem extends
> > >> to just perf-record. With perf-record exclude_guest defaults to 1. See
> > >> tools/perf/util/util.c, event_attr_init().
> > >
> > > You lost me there.. so perf-record defaults to exclude_guest=1 (which
> > > would make the proposed patch I just send actually possible), but its
> > > still going *bang* ?
> >
> > It's possible that the DS writes overshoot the MSR... or that there's a
> > bug somewhere.
> >
> I hope it is the later, because we can do nothing with the former.
>
Actually we can disable DS before guest entry.

--
Gleb.
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