On Sat, Jan 29, 2022 at 9:06 AM Jason Wang <jasow...@redhat.com> wrote:
>
>
> 在 2022/1/22 上午4:27, Eugenio Pérez 写道:
> > Signed-off-by: Eugenio Pérez <epere...@redhat.com>
> > ---
> > hw/virtio/vhost-vdpa.c | 20 ++++++++++++++++++--
> > 1 file changed, 18 insertions(+), 2 deletions(-)
> >
> > diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
> > index 18de14f0fb..029f98feee 100644
> > --- a/hw/virtio/vhost-vdpa.c
> > +++ b/hw/virtio/vhost-vdpa.c
> > @@ -687,13 +687,29 @@ static int vhost_vdpa_set_vring_kick(struct vhost_dev
> > *dev,
> > }
> > }
> >
> > -static int vhost_vdpa_set_vring_call(struct vhost_dev *dev,
> > - struct vhost_vring_file *file)
> > +static int vhost_vdpa_set_vring_dev_call(struct vhost_dev *dev,
> > + struct vhost_vring_file *file)
> > {
> > trace_vhost_vdpa_set_vring_call(dev, file->index, file->fd);
> > return vhost_vdpa_call(dev, VHOST_SET_VRING_CALL, file);
> > }
> >
> > +static int vhost_vdpa_set_vring_call(struct vhost_dev *dev,
> > + struct vhost_vring_file *file)
> > +{
> > + struct vhost_vdpa *v = dev->opaque;
> > +
> > + if (v->shadow_vqs_enabled) {
> > + int vdpa_idx = vhost_vdpa_get_vq_index(dev, file->index);
> > + VhostShadowVirtqueue *svq = g_ptr_array_index(v->shadow_vqs,
> > vdpa_idx);
> > +
> > + vhost_svq_set_guest_call_notifier(svq, file->fd);
>
>
> Two questions here (had similar questions for vring kick):
>
> 1) Any reason that we setup the eventfd for vhost-vdpa in
> vhost_vdpa_svq_setup() not here?
>
I'm not sure what you mean.
The guest->SVQ call and kick fds are set here and at
vhost_vdpa_set_vring_kick. The event notifier handler of the guest ->
SVQ kick_fd is set at vhost_vdpa_set_vring_kick /
vhost_svq_set_svq_kick_fd. The guest -> SVQ call fd has no event
notifier handler since we don't poll it.
On the other hand, the connection SVQ <-> device uses the same fds
from the beginning to the end, and they will not change with, for
example, call fd masking. That's why it's setup from
vhost_vdpa_svq_setup. Delaying to vhost_vdpa_set_vring_call would make
us add way more logic there.
> 2) The call could be disabled by using -1 as the fd, I don't see any
> code to deal with that.
>
Right, I didn't take that into account. vhost-kernel takes also -1 as
kick_fd to unbind, so SVQ can be reworked to take that into account
for sure.
Thanks!
> Thanks
>
>
> > + return 0;
> > + } else {
> > + return vhost_vdpa_set_vring_dev_call(dev, file);
> > + }
> > +}
> > +
> > /**
> > * Set shadow virtqueue descriptors to the device
> > *
>
