Re: [Qemu-devel] E5-2620v2 - emulation stop error

Paolo Bonzini
2015-04-01T12:05:54Z

On 01/04/2015 13:49, Radim Krčmář wrote:
> 2015-03-31 21:23+0300, Andrey Korolyov:
>> On Tue, Mar 31, 2015 at 9:04 PM, Bandan Das <bsd@redhat.com> wrote:
>>> Bandan Das <bsd@redhat.com> writes:
>>>> Andrey Korolyov <andrey@xdel.ru> writes:
>>>> ...
>>>>> http://xdel.ru/downloads/kvm-e5v2-issue/another-tracepoint-fail-with-apicv.dat.gz
>>>>>
>>>>> Something a bit more interesting, but the mess is happening just
>>>>> *after* NMI firing.
>>>>
>>>> What happens if NMI is turned off on the host ?
>>>
>>> Sorry, I meant the watchdog..
>>
>> Thanks, everything goes well (as it probably should go there):
>> http://xdel.ru/downloads/kvm-e5v2-issue/apicv-enabled-nmi-disabled.dat.gz
>
> Nice revelation!

Yes, pretty random but good to know. Can you try again with the
nmi/nmi_handler tracepoint also?

Paolo

> KVM doesn't expect host's NMIs to look like this so it doesn't pass them
> to the host. What was the watchdog that casually sent NMIs?
> (It worked after "nmi_watchdog=0" on the host?)
>
> (Guest's NMI should have a different result as well. NMI_EXCEPTION is
> an expected exit reason for guest's hard exceptions, they are then
> differentiated by intr_info and nothing hinted that this was a NMI.)
>