Re: [KVM PATCH v8 3/3] KVM: add iosignalfd support

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

On Tue, Jun 23, 2009 at 07:33:07AM -0400, Gregory Haskins wrote:
> Michael S. Tsirkin wrote:
> > On Thu, Jun 18, 2009 at 08:30:46PM -0400, Gregory Haskins wrote:
> >   
> >> +static int
> >> +iosignalfd_group_in_range(struct kvm_io_device *this, gpa_t addr, int len,
> >> +			  int is_write)
> >> +{
> >> +	struct _iosignalfd_group *p = to_group(this);
> >> +
> >> +	return ((addr >= p->addr && (addr < p->addr + p->length)));
> >> +}
> >>     
> >
> > I think I see a problem here. For virtio, we do not necessarily want all
> > virtqueues for a device to live in kernel: there might be control
> > virtqueues that we want to leave in userspace. Since this claims all
> > writes to a specific address, the signal never makes it to userspace.
> >
> >   
> You can use a wildcard.  Would that work?
> 

Nope, you need to know the value written.