RE: [PATCH v8 2/3] x86, apicv: add virtual interrupt delivery support

Zhang, Yang Z
2013-01-10T00:22:15Z

Marcelo Tosatti wrote on 2013-01-09:
> On Wed, Jan 09, 2013 at 08:07:31AM +0000, Zhang, Yang Z wrote:
>>>> if(check_request(KVM_REQ_, ....)) {
>>>> ioapic_lock(); (*)
>>>> update local EOI exit bitmap from IOAPIC
>> In my patch, it traverses IOAPIC entry once and only updates target
>> vcpus's eoi exit bitmap. Then make request for all vcpus. With your
>> suggestion , all vcpus will traverse all IOAPIC entries. Though ioapic
> entry write is rare, it's still not reasonable.
>
> It should be fast, and very rare (as in once during system
> initialization, or device hotplug).
Ok. Will revise the patch follow your suggestion.

>
> Is there a particular case that makes it necessary to optimize scanning?
No.

>>
>>>> ioapic_unlock();
>>>> }
>>>>
>>> Fine by me. Looks simpler.
>>>
>>>>
>>>>
>>>> (*) plus any other lock that paths that update the map take
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>>
>>>>> Best regards,
>>>>> Yang
>>>
>>> --
>>> Gleb.
>>
>>
>> Best regards,
>> Yang

Best regards,
Yang