On 2011-05-18 21:34, Anthony Liguori wrote:
> On 05/18/2011 02:27 PM, Jan Kiszka wrote:
>> On 2011-05-18 21:10, Anthony Liguori wrote:
>>> On 05/18/2011 10:30 AM, Jan Kiszka wrote:
>>> You really don't need to register 90% of the time.  In the case of a PC
>>> with i440fx, it's really quite simple:
>>>
>>> if an I/O is to the APIC page,
>>>     it's handled by the APIC
>>
>> That's not that simple. We need to tell apart:
>>   - if a cpu issued the request, and which one =>  forward to APIC
> 
> Right, but what I'm saying is that this logic lives in
> kvm-all.c:kvm_run():case EXIT_MMIO.
> 
> Obviously for TCG, it's a bit more complicated but this should be
> handled way before there's any kind of general dispatch.

Hmm, checking again, I think the APIC should not show up here at all. We
really need to filter it out very early at CPU level, i.e. when creating
the iotlb (or when dispatching a KVM EXIT_MMIO). It's cpu local, nothing
the chipset will ever see.

I really wonder now why I dropped the idea of handling per-cpu regions
as a special case in tlb_set_page. It looks trivial, could even be done
with a linear per-cpu list before looking at any chipset mappings.

Jan