Re: [PATCH v2 1/6] kvm: Pass kvm_irqfd to functions

["Michael S. Tsirkin" <mst@redhat.com>]

On Thu, Jun 28, 2012 at 11:03:16AM +0200, Cornelia Huck wrote:
> On Thu, 28 Jun 2012 11:38:57 +0300
> "Michael S. Tsirkin" <mst@redhat.com> wrote:
> 
> > On Wed, Jun 27, 2012 at 04:24:30PM +0200, Cornelia Huck wrote:
> > > On Tue, 26 Jun 2012 23:09:04 -0600
> > > Alex Williamson <alex.williamson@redhat.com> wrote:
> > > 
> > > > Prune this down to just the struct kvm_irqfd so we can avoid
> > > > changing function definition for every flag or field we use.
> > > > 
> > > > Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
> > > 
> > > I'm currently trying to find a way to make irqfd workable for s390
> > > which will likely include using a new field in kvm_irqfd, so I'd like
> > > to have this change (and I also think it makes the code nicer to read).
> > > So:
> > > 
> > > Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
> > 
> > Unfortunately it looks like we are not sanitizing kvm_irqfd
> > at all so we won't be able to use the padding :(
> > We'll need a new ioctl instead.
> > 
> 
> How about something like this as parameter for the new ioctl?
> 
> struct kvm_irqfd2 {
> 	__u32 fd;
> 	__u32 flags;  /* for things like deassign */
> 	__u64 type;   /* determines the payload */
> 	union {
> 		/* type traditional */
> 		struct {
> 			__u32 gsi;
> 		} trad;
> 		/* type s390 */
> 		struct {
> 			__u32 int_type;
> 			__u32 parm;
> 			__u64 parm64;
> 		} s390;
> 		__u8 pad[20];
> 	};
> }
> 
> This could be combined with an arch or a per-kvm callback to keep the
> generic code clean of architecture dependencies.
> 
> Cornelia

Looks a bit weird - shouldn't all this be part of gsi routing?
But no idea really, I don't see the big picture here.