Re: [Xen-devel] [PATCH] Dont' round-robin the callback interrupt

[Keir Fraser <keir.fraser@xxxxxxxxxxxxx>]

On 12/07/2010 17:05, "Keir Fraser" <keir.fraser@xxxxxxxxxxxxx> wrote:

> On 12/07/2010 16:52, "Paul Durrant" <paul.durrant@xxxxxxxxxx> wrote:
> 
>> Dont' round-robin the callback interrupt.
>> 
>> Arrange that the event channel callback interrupt always goes to the
>> lowest vcpu with a matching local apic. This should, in most cases,
>> be VCPU0 (to which all event channels are bound for HVM guests) but
>> this cannot be guaranteed.
>> 
>> Signed-off-by: Paul Durrant <paul.durrant@xxxxxxxxxx>
>> CC: Tim Deegan <tim.deegan@xxxxxxxxxx>
> 
> PV drivers should be handling callback on CPU != 0. The example Linux PV
> drivers have done that for a very long time indeed. If a workaround is
> needed for broken drivers then we need some way to gate it, and we should in
> that case force delivery to VCPU0, as we do for some timer interrupts. The
> forcing appears to do no harm even if not architecturally correct, and after
> all we would be going to these lengths only because delivery to VCPU-not-0
> *certainly* doesn't work.

Actually given this is probably XS/XCP Win drivers we're talking about,
aren't they expected to be upgraded when moving to an upgraded host? In
which case the fix should be in the upgraded drivers?

 -- Keir




_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel