Re: CPU hotplug add seems broken

[Anthony Liguori <anthony@codemonkey.ws>]

On 01/11/2010 04:50 AM, Avi Kivity wrote:
> On 01/11/2010 12:42 PM, Gleb Natapov wrote:
>>>>
>>>> That cool, but SVVP complains.
>>> What's the complaint?  Maybe we can fix it instead of rewriting things.
>>>
>> https://bugzilla.redhat.com/show_bug.cgi?id=49584://bugzilla.redhat.com/show_bug.cgi?id=495844 
>>
>> Hope it accessible to everyone but if not SVVP complains:
>> Run "Signed Driver check" of SVVP testing, the (Qemu virtual CPU verison
>> 0.9.1) has error.
>>
>> The only why to fix it that I can see is to not present disabled MADT
>> entries for Windows and that will require us to provide some kind
>> of flag to QEMU. The cleanest way is to create disabled MADT entries
>> only if max-cpus != startup cpus and run Windows only with max-cpus ==
>> startup cpus. The problem is 1) you have to know what is your guest
>> at startup time 2) will require creation of SSDT for Processors()
>> on the fly (or precompile them for every value of max-cpus and load
>> dynamically). Actually there is a third solution that I just thought
>> about but I need to test it first :).
>
> Perhaps loading a processor driver will fix this issue (which driver 
> can also perform the hotplug).
>
>> Anyway all those solution do not
>> guaranty that we will be able to do cpu hotplug on Windows since we
>> don't yet know what Windows expects.
>
> I'm sure we'll be able to eventually.

win2k8 supports CPU hotplug with VMware.  I'd suggest someone fire up 
VMware and dump the ACPI tables to try and see how they're doing it.  
Otherwise, if someone has a physical machine that is known to do CPU 
hotplug with win2k8, an acpi dump would be useful there.

I think it's easier to make sure Linux works with what Windows currently 
supports than vice versa.

Regards,

Anthony Liguori