Re: [Xen-ia64-devel] vIOSAPIC and IRQs delivery

[Tristan Gingold <Tristan.Gingold@xxxxxxxx>]

Le Mardi 07 Mars 2006 09:47, Tristan Gingold a écrit :
> Le Lundi 06 Mars 2006 22:26, Magenheimer, Dan (HP Labs Fort Collins) a écrit 
:
> > Hi Tristan --
> >
> > Do you have any more design information?  I'm not very
> > familiar with the x86 implementation but is it your intent
> > for it to be (nearly) identical?  What would be different?
>
> First, I describe what I have done.
> My patch moved IOSAPIC control from dom0 to Xen.  dom0 still know all about
> IOSAPIC, but program it through hypercalls (physdev_op).
>
> This model could handle IRQs for Xen (serial console), could handle driver
> domains and virtualize LID. I think these are the main advantages.
>
> The cons is certainly speed: an hypercall is required to do EOI (overhead
> to be mesured), and hypercalls are also required to program IOSAPIC (I
> think this is insignifiant).
>
> Also note that my patch makes very few changes to the linux iosapic.c
>
> I really think that vIOSAPIC is required (wether using my patch or not is
> another question).
Just to complete:

my patch is not yet ready for driver-domain.  Futhermore, I started to think 
about this without looking on x86 code.  This part should be rewritten.
I won't do this now as I can't test, but I promize to do it as soon as we work 
on driver domains.

Tristan.


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