Re: [KVM PATCH v9 2/2] KVM: add iosignalfd support

Michael S. Tsirkin
2009-07-07T12:52:36Z

On Tue, Jul 07, 2009 at 03:27:49PM +0300, Avi Kivity wrote:
> On 07/07/2009 03:22 PM, Michael S. Tsirkin wrote:
>> On Tue, Jul 07, 2009 at 02:53:18PM +0300, Avi Kivity wrote:
>>
>>>>> + /* address-range must be precise for a hit */
>>>>>
>>>>>
>>>> So there's apparently no way to specify that
>>>> you want 1,2, or 4 byte writes at address X?
>>>>
>>>>
>>> Why would you want that?
>>>
>>
>> Donnu. Why would anyone want to catch 8 byte writes at all?
>>
>
> One of the natural write sizes.
>
>> Seriously, why add artificial limitations?
>> IMO, addr=0,len=1 and addr=0,len=2 should not conflict.
>>
>>
>
> They should not conflict, but a two byte write need not hit a one byte
> registration.

Yes. That's exactly what I'm saying. I think it should be possible to
create 2 fds:

addr = 0
len = 1
addr = 0
len = 2
and at most one will ever trigger.

But current code will not let you create the second one.

--
MST