[PATCH RFC 08/15] hw/virtio/vhost-shadow-virtqueue: used handler

Adds a handler callback to shadow virtqueues in order to enable
non-default processing of used vring elements from the device.

Signed-off-by: Connor Kite <[email protected]>
---
 hw/virtio/vhost-shadow-virtqueue.c |  4 ++++
 hw/virtio/vhost-shadow-virtqueue.h | 14 ++++++++++++++
 2 files changed, 18 insertions(+)

diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c
index bcb7f2ffc7..eb86c1ee37 100644
--- a/hw/virtio/vhost-shadow-virtqueue.c
+++ b/hw/virtio/vhost-shadow-virtqueue.c
@@ -669,6 +669,10 @@ static void vhost_svq_flush(VhostShadowVirtqueue *svq,
                 break;
             }
 
+            if (svq->ops && svq->ops->used_handler) {
+                svq->ops->used_handler(svq, elem, svq->ops_opaque);
+            }
+
             if (unlikely(i >= svq->vring.num)) {
                 qemu_log_mask(LOG_GUEST_ERROR,
                          "More than %u used buffers obtained in a %u size SVQ",
diff --git a/hw/virtio/vhost-shadow-virtqueue.h b/hw/virtio/vhost-shadow-virtqueue.h
index ec16a1e838..ccfeee36d7 100644
--- a/hw/virtio/vhost-shadow-virtqueue.h
+++ b/hw/virtio/vhost-shadow-virtqueue.h
@@ -56,8 +56,22 @@ typedef int (*VirtQueueAvailCallback)(VhostShadowVirtqueue *svq,
                                       VirtQueueElement *elem,
                                       void *vq_callback_opaque);
 
+/**
+ * Callback to handle a used buffer
+ *
+ * @svq: Shadow virtqueue
+ * @elem: Element placed in the queue by the device
+ * @vq_callback_opaque: Used to pass arguments to callback
+ *
+ * Returns 0 if the vq is running as expected
+ */
+typedef int (*VirtQueueUsedCallback)(VhostShadowVirtqueue *svq,
+                                      VirtQueueElement *elem,
+                                      void *vq_callback_opaque);
+
 typedef struct VhostShadowVirtqueueOps {
     VirtQueueAvailCallback avail_handler;
+    VirtQueueUsedCallback used_handler;
 } VhostShadowVirtqueueOps;
 
 /* Shadow virtqueue to relay notifications */

-- 
2.43.0