[RFC PATCH 07/12] vhost: Add VhostVDPAStartOp operation

["Eugenio Pérez" <eperezma@redhat.com>]

It allows to run commands at start of the device, before it have enabled
any queue.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
---
 hw/virtio/vhost-shadow-virtqueue.h | 3 +++
 include/hw/virtio/vhost-vdpa.h     | 5 +++++
 hw/virtio/vhost-vdpa.c             | 8 ++++++++
 3 files changed, 16 insertions(+)

diff --git a/hw/virtio/vhost-shadow-virtqueue.h b/hw/virtio/vhost-shadow-virtqueue.h
index 03eb7ff670..210fe393cd 100644
--- a/hw/virtio/vhost-shadow-virtqueue.h
+++ b/hw/virtio/vhost-shadow-virtqueue.h
@@ -26,6 +26,8 @@ typedef struct SVQDescState {
 } SVQDescState;
 
 typedef struct VhostShadowVirtqueue VhostShadowVirtqueue;
+typedef int (*ShadowVirtQueueStart)(VhostShadowVirtqueue *svq,
+                                    void *opaque);
 
 /**
  * Callback to handle an avail buffer.
@@ -43,6 +45,7 @@ typedef int (*VirtQueueAvailCallback)(VhostShadowVirtqueue *svq,
                                       void *vq_callback_opaque);
 
 typedef struct VhostShadowVirtqueueOps {
+    ShadowVirtQueueStart start;
     VirtQueueAvailCallback avail_handler;
 } VhostShadowVirtqueueOps;
 
diff --git a/include/hw/virtio/vhost-vdpa.h b/include/hw/virtio/vhost-vdpa.h
index d10a89303e..b7d18b4e30 100644
--- a/include/hw/virtio/vhost-vdpa.h
+++ b/include/hw/virtio/vhost-vdpa.h
@@ -24,6 +24,10 @@ typedef struct VhostVDPAHostNotifier {
     void *addr;
 } VhostVDPAHostNotifier;
 
+struct vhost_vdpa;
+/* Called after send DRIVER_OK but after enabling vrings */
+typedef int (*VhostVDPAStartOp)(struct vhost_vdpa *v);
+
 typedef struct vhost_vdpa {
     int device_fd;
     int index;
@@ -39,6 +43,7 @@ typedef struct vhost_vdpa {
     GPtrArray *shadow_vqs;
     const VhostShadowVirtqueueOps *shadow_vq_ops;
     void *shadow_vq_ops_opaque;
+    VhostVDPAStartOp start_op;
     struct vhost_dev *dev;
     VhostVDPAHostNotifier notifier[VIRTIO_QUEUE_MAX];
 } VhostVDPA;
diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
index 1d8829c619..48f031b8c0 100644
--- a/hw/virtio/vhost-vdpa.c
+++ b/hw/virtio/vhost-vdpa.c
@@ -1136,6 +1136,14 @@ static int vhost_vdpa_dev_start(struct vhost_dev *dev, bool started)
         if (unlikely(r)) {
             return r;
         }
+
+        if (v->start_op) {
+            r = v->start_op(v);
+            if (unlikely(r)) {
+                return r;
+            }
+        }
+
         vhost_vdpa_set_vring_ready(dev);
     } else {
         vhost_vdpa_reset_device(dev);
-- 
2.31.1