Re: [PATCH V6 04/10] xen/arm: Use cpumask_t type for vcpu_mask in vgic_to_sgi

[Ian Campbell <ian.campbell@citrix.com>]

On Wed, 2015-06-10 at 18:21 +0800, Chen Baozi wrote:
> > Perhaps we want to bite the bullet now and change the vgic_to_sgi to
> > take an affinity path thing (aff3.aff2.aff1) + target list, instead of a
> > cpumask? That makes sense given the 16 CPU per AFF0 limitation, since
> > there is only a limited set of cpumask patterns which can be specified,
> > so we don't need the fully arbitrary bitmap.
> 
> It seems that only GICv3 supports affinity level. And vgic_to_sgi is shared
> by both vGICv2 and vGICv3... However, we can make aff3==aff2==aff1==0 and put
> the 8-bit GICv2 cpumask in the target list. If this is good for vGICv2, I
> have no problem on it.

I think that makes sense, we can have gicv2 assert that aff3..1 == 0 (or
the corresponding argument which encodes them all).

The alternative would be to refactor somehow such that the generic
interface was suitable for both and the difference becomes internal.

Ian.