On Thu, Mar 16, 2023 at 5:25 PM Jason Wang <jasowang@xxxxxxxxxx> wrote:
>
>
> 在 2023/2/28 17:41, Xie Yongji 写道:
> > Add eventfd for the vdpa callback so that user
> > can signal it directly instead of running the
> > callback. It will be used for vhost-vdpa case.
> >
> > Signed-off-by: Xie Yongji <xieyongji@xxxxxxxxxxxxx>
> > ---
> > drivers/vhost/vdpa.c | 2 ++
> > drivers/virtio/virtio_vdpa.c | 1 +
> > include/linux/vdpa.h | 3 +++
> > 3 files changed, 6 insertions(+)
> >
> > diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
> > index dc12dbd5b43b..ae89c0ccc2bb 100644
> > --- a/drivers/vhost/vdpa.c
> > +++ b/drivers/vhost/vdpa.c
> > @@ -599,9 +599,11 @@ static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd,
> > if (vq->call_ctx.ctx) {
> > cb.callback = vhost_vdpa_virtqueue_cb;
> > cb.private = vq;
> > + cb.irq_ctx = vq->call_ctx.ctx;
> > } else {
> > cb.callback = NULL;
> > cb.private = NULL;
> > + cb.irq_ctx = NULL;
> > }
> > ops->set_vq_cb(vdpa, idx, &cb);
> > vhost_vdpa_setup_vq_irq(v, idx);
> > diff --git a/drivers/virtio/virtio_vdpa.c b/drivers/virtio/virtio_vdpa.c
> > index 9eee8afabda8..a5cecafbc2d1 100644
> > --- a/drivers/virtio/virtio_vdpa.c
> > +++ b/drivers/virtio/virtio_vdpa.c
> > @@ -195,6 +195,7 @@ virtio_vdpa_setup_vq(struct virtio_device *vdev, unsigned int index,
> > /* Setup virtqueue callback */
> > cb.callback = callback ? virtio_vdpa_virtqueue_cb : NULL;
> > cb.private = info;
> > + cb.irq_ctx = NULL;
> > ops->set_vq_cb(vdpa, index, &cb);
> > ops->set_vq_num(vdpa, index, virtqueue_get_vring_size(vq));
> >
> > diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h
> > index 10bd22387276..94a7ec49583a 100644
> > --- a/include/linux/vdpa.h
> > +++ b/include/linux/vdpa.h
> > @@ -13,10 +13,13 @@
> > * struct vdpa_calllback - vDPA callback definition.
> > * @callback: interrupt callback function
> > * @private: the data passed to the callback function
> > + * @irq_ctx: the eventfd for the callback, user can signal
> > + * it directly instead of running the callback
>
>
> I'd suggest to do more tweaks to mention:
>
> 1) irq_ctx is optional
> 2) that when the irq_ctx is set, the vDPA driver must guarantee that
> signaling it is functional equivalent to triggering the callback. When
> set, vDPA parent can signal it directly instead of triggering the callback.
>
> > */
> > struct vdpa_callback {
> > irqreturn_t (*callback)(void *data);
> > void *private;
> > + struct eventfd_ctx *irq_ctx;
>
>
> There's no IRQ concept at the virtual vDPA bus level, so it's probably
> better to rename it as "trigger".
>
> Btw, should we select EVENTFD for vDPA?
Looks like we are fine here since we only use the pointer to the eventfd_ctx.
Thanks
>
> Thanks
>
>
> > };
> >
> > /**
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