Re: [PATCH] KVM: PPC: e500: Don't hardcode PIR=0

Alexander Graf
2011-09-02T19:46:19Z

On 02.09.2011, at 21:35, Scott Wood wrote:

> On 09/02/2011 02:23 PM, Alexander Graf wrote:
>>
>> On 02.09.2011, at 20:14, Scott Wood wrote:
>>
>>> On 09/02/2011 10:12 AM, Alexander Graf wrote:
>>>>
>>>> Am 02.09.2011 um 01:08 schrieb Scott Wood <scottwood@freescale.com>:
>>>>
>>>>> Signed-off-by: Scott Wood <scottwood@freescale.com>
>>>>
>>>> Patch description missing.
>>>
>>> It's not missing, it's just brief. :-)
>>>
>>> I suppose you could add "The hardcoded behavior prevents SMP support.
>>> QEMU shall specify the vcpu's PIR as the vcpu id".
>>
>> Ok, let me get my head around this. Before, PIR was forced to 0 by
>> the setup code and set_sregs with PIR != 0 failed. Now it's simply
>> vcpu_id which is already the correct value. Why didn't I run into
>> this failure? Why did SMP work for me at all then? Shouldn't the
>> guest be completely confused and find two CPU 0s?
>
> I was wondering about that myself. It looks like PIR isn't used much in
> Linux on e500v2. There's no msgsnd. It's used to for
> __secondary_hold_acknowledge, but that has a silent timeout.

Interesting. Well - either way. Just resend with a proper patch description and I'll apply it :)

Alex