vhost-vdpa: add support for config interrupt

Add new call back function in vhost-vdpa, this function will
set the event fd to kernel. This function will be called
in the vhost_dev_start and vhost_dev_stop

Signed-off-by: Cindy Lu <lulu@redhat.com>
Message-Id: <20211104164827.21911-6-lulu@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

hw/virtio/trace-events

@@ -53,6 +53,7 @@ vhost_vdpa_get_features(void *dev, uint64_t features) "dev: %p features: 0x%"PRI
 vhost_vdpa_set_owner(void *dev) "dev: %p"
 vhost_vdpa_vq_get_addr(void *dev, void *vq, uint64_t desc_user_addr, uint64_t avail_user_addr, uint64_t used_user_addr) "dev: %p vq: %p desc_user_addr: 0x%"PRIx64" avail_user_addr: 0x%"PRIx64" used_user_addr: 0x%"PRIx64
 vhost_vdpa_get_iova_range(void *dev, uint64_t first, uint64_t last) "dev: %p first: 0x%"PRIx64" last: 0x%"PRIx64
+vhost_vdpa_set_config_call(void *dev, int fd)"dev: %p fd: %d"
 
 # virtio.c
 virtqueue_alloc_element(void *elem, size_t sz, unsigned in_num, unsigned out_num) "elem %p size %zd in_num %u out_num %u"

hw/virtio/vhost-vdpa.c

@@ -725,6 +725,12 @@ static int vhost_vdpa_set_vring_call(struct vhost_dev *dev,
     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_config_call(struct vhost_dev *dev,
+                                       int fd)
+{
+    trace_vhost_vdpa_set_config_call(dev, fd);
+    return vhost_vdpa_call(dev, VHOST_VDPA_SET_CONFIG_CALL, &fd);
+}
 
 static int vhost_vdpa_get_features(struct vhost_dev *dev,
                                      uint64_t *features)
@@ -795,4 +801,5 @@ const VhostOps vdpa_ops = {
         .vhost_get_device_id = vhost_vdpa_get_device_id,
         .vhost_vq_get_addr = vhost_vdpa_vq_get_addr,
         .vhost_force_iommu = vhost_vdpa_force_iommu,
+        .vhost_set_config_call = vhost_vdpa_set_config_call,
 };