Re: [nVMX with: v3.9-11789-ge0fd9af] Stack trace when L2 guest is rebooted.

[Jan Kiszka <jan.kiszka@siemens.com>]

On 2013-05-13 08:45, Ren, Yongjie wrote:
>> -----Original Message-----
>> From: kvm-owner@vger.kernel.org [mailto:kvm-owner@vger.kernel.org]
>> On Behalf Of Gleb Natapov
>> Sent: Monday, May 13, 2013 2:39 PM
>> To: Jan Kiszka
>> Cc: Kashyap Chamarthy; Abel Gordon; Nakajima, Jun;
>> kvm@vger.kernel.org; kvm-owner@vger.kernel.org
>> Subject: Re: [nVMX with: v3.9-11789-ge0fd9af] Stack trace when L2 guest
>> is rebooted.
>>
>> On Mon, May 13, 2013 at 08:31:33AM +0200, Jan Kiszka wrote:
>>> On 2013-05-12 18:52, Kashyap Chamarthy wrote:
>>>>>> --------------------
>>>>>> ....
>>>>>> [  217.938034] Uhhuh. NMI received for unknown reason 30 on CPU
>> 0.
>>>>>> [  217.938034] Do you have a strange power saving mode enabled?
>>>>>> .[  222.523373] Uhhuh. NMI received for unknown reason 20 on
>> CPU 0.
>>>>>> [  222.524073] Do you have a strange power saving mode enabled?
>>>>>> [  222.524073] Dazed and confused, but trying to continue
>>>>>> [  243.860319] Uhhuh. NMI received for unknown reason 30 on CPU
>> 0
>>>>>> .....
>>>>>> --------------------
>>>>>> At the moment, L2 guest creation stuck at the above message
>>>>>>
>>>>> Are those in L2 dmesg or L1?
>>>>
>>>> L2 dmesg.
>>>>
>>>>
>>>>>> $ cat /etc/grub2.cfg  | egrep -i 'hpet|nmi'
>>>>>>
>>>>> IIRC watchdog is enabled by default.
>>>>
>>>> Indeed, you're right. I disabled NMI on L1, and rebooted the newly
>>>> created L2 guest starts just fine.
>>>
>>> NMI watchdogs go via some perf counters theses days IIRC. Can anyone
>>> tell me which of those may be used in Kashyap's setup? I'm probably
>>> lacking them for my guests and therefore do not see the errors.
>>>
>> Try running with -cpu host for L1. Your CPU definition probably lacks
>> PMU leaf.
>>
> I met the same NMI issue in L2, too.
> L1: -cpu host  (or -cpu Haswell,+vmx)
> L2: -cpu qemu64 by default
> 
> If I use '-cpu qemu64,+vmx' to create L1, I'll not meet NMI issue in L2.
> 

That, and it looks like my guest kernel was lacking
CONFIG_LOCKUP_DETECTOR. Will rebuild and retest later.

Jan

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