virtio: introduce virtio_queue_enable()

Introduce the interface queue_enable() in VirtioDeviceClass and the
fucntion virtio_queue_enable() in virtio, it can be called when
VIRTIO_PCI_COMMON_Q_ENABLE is written and related virtqueue can be
started. It only supports the devices of virtio 1 or later. The
not-supported devices can only start the virtqueue when DRIVER_OK.

Signed-off-by: Kangjie Xu <kangjie.xu@linux.alibaba.com>
Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20221017092558.111082-4-xuanzhuo@linux.alibaba.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index cf5f9ca387..9683b2e158 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -2495,6 +2495,20 @@ void virtio_queue_reset(VirtIODevice *vdev, uint32_t queue_index)
     __virtio_queue_reset(vdev, queue_index);
 }
 
+void virtio_queue_enable(VirtIODevice *vdev, uint32_t queue_index)
+{
+    VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
+
+    if (!virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
+        error_report("queue_enable is only suppported in devices of virtio "
+                     "1.0 or later.");
+    }
+
+    if (k->queue_enable) {
+        k->queue_enable(vdev, queue_index);
+    }
+}
+
 void virtio_reset(void *opaque)
 {
     VirtIODevice *vdev = opaque;