[PATCH v4 04/15] virtio: introduce virtio_queue_enable()

[Kangjie Xu]

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>
---
 hw/virtio/virtio.c         | 14 ++++++++++++++
 include/hw/virtio/virtio.h |  2 ++
 2 files changed, 16 insertions(+)

diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index 0e9d41366f..141f18c633 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -2050,6 +2050,20 @@ 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;
diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
index 879394299b..085997d8f3 100644
--- a/include/hw/virtio/virtio.h
+++ b/include/hw/virtio/virtio.h
@@ -131,6 +131,7 @@ struct VirtioDeviceClass {
     void (*reset)(VirtIODevice *vdev);
     void (*set_status)(VirtIODevice *vdev, uint8_t val);
     void (*queue_reset)(VirtIODevice *vdev, uint32_t queue_index);
+    void (*queue_enable)(VirtIODevice *vdev, uint32_t queue_index);
     /* For transitional devices, this is a bitmap of features
      * that are only exposed on the legacy interface but not
      * the modern one.
@@ -270,6 +271,7 @@ int virtio_queue_set_host_notifier_mr(VirtIODevice *vdev, 
int n,
 int virtio_set_status(VirtIODevice *vdev, uint8_t val);
 void virtio_reset(void *opaque);
 void virtio_queue_reset(VirtIODevice *vdev, uint32_t queue_index);
+void virtio_queue_enable(VirtIODevice *vdev, uint32_t queue_index);
 void virtio_update_irq(VirtIODevice *vdev);
 int virtio_set_features(VirtIODevice *vdev, uint64_t val);
 
-- 
2.32.0