Re: [Qemu-devel] [PATCH 0/4] s390: Allow hotplug of s390 CPUs

[Andreas Färber]

Am 09.11.2015 um 16:37 schrieb Christian Borntraeger:
> Am 09.11.2015 um 16:35 schrieb Christian Borntraeger:
>> Am 09.11.2015 um 16:28 schrieb Andreas Färber:
>>> Hi,
>>>
>>> Am 09.11.2015 um 16:17 schrieb Matthew Rosato:
>>>> To subsequently hotplug a CPU:
>>>>
>>>> Issue 'cpu-add <id>' from qemu monitor, or use virsh setvcpus --count <n> 
>>>> <domain>, where <n> is the total number of desired guest CPUs.
>>>
>>> What exactly is still missing for you to use the standard device_add?
>>>
>>> Last time I checked (a while ago...) some patches were stuck on the x86
>>> side, and I don't recall hearing any feedback from the s390x side in my
>>> KVM Forum CPU hotplug session.
>>
>> libvirt uses "cpu-add" unconditionally for hotplugging, so we certainly 
>> want to support that. 
> 
> Sorry, hit send too early. I assume you want us to support device_add of
> a CPU in addition to that. Correct? 

No, I mean as I've always said: cpu-add was a short-term hack to make
CPU hotplug work on x86. libvirt certainly needs to be fixed if it
assumes this to work for s390.

If device_add works, we don't need cpu-add. If device_add does not work,
we need to know which patches are missing. device_del is a separate
beast and there were also patches around that seemed incomplete
according to Eduardo.

Bharata did implement device_add for pseries, I thought.

Regards,
Andreas

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