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    SubjectRe: [V2 PATCH 0/6] x86, NMI: give NMI handler a face-lift
    On Thu, Nov 18, 2010 at 01:51:44PM -0600, Jason Wessel wrote:
    > > So the problem is when the nmi watchdog is enabled, the perf event is
    > > 'active' and thus tries to read the counter value. Because it is always
    > > zero, perf just assumes the counter overflowed and the NMI is his.
    > >
    > > Not sure how to fix it yet, other than include the logic that detects we
    > > are on a guest and disable perf??
    > >
    > >
    > 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

    Well I think Peter does not have a positive opinion about emulating perf
    inside a guest. Nor are the KVM folks having much success in doing so.

    Just to clarify, perf counter emulation is _not_ implemented in kvm.
    Therefore disabling perf in the guest makes sense until someone gets
    around to actually writing the emulation code for perf in a guest. :-)


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