vdpa: Add eventfd for the vdpa callback

Add eventfd for the vdpa callback so that user
can signal it directly instead of triggering the
callback. It will be used for vhost-vdpa case.

Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
Message-Id: <20230323053043.35-9-xieyongji@bytedance.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>

diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index 7be9d9d..9cd878e 100644 (file)
--- 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.trigger = vq->call_ctx.ctx;
                } else {
                        cb.callback = NULL;
                        cb.private = NULL;
+                       cb.trigger = 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 f3826f4..2a095f3 100644 (file)
--- a/drivers/virtio/virtio_vdpa.c
+++ b/drivers/virtio/virtio_vdpa.c
@@ -196,6 +196,7 @@ 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.trigger = 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 2313db7..f2064fa 100644 (file)
--- a/include/linux/vdpa.h
+++ b/include/linux/vdpa.h
@@ -13,10 +13,16 @@
  * struct vdpa_calllback - vDPA callback definition.
  * @callback: interrupt callback function
  * @private: the data passed to the callback function
+ * @trigger: the eventfd for the callback (Optional).
+ *           When it is set, the vDPA driver must guarantee that
+ *           signaling it is functional equivalent to triggering
+ *           the callback. Then vDPA parent can signal it directly
+ *           instead of triggering the callback.
  */
 struct vdpa_callback {
        irqreturn_t (*callback)(void *data);
        void *private;
+       struct eventfd_ctx *trigger;
 };
 
 /**