[Qemu-devel] [PATCH V3 10/14] virtio: introduce virtio_queue_get_index()

[Jason Wang <jasowang@redhat.com>]

This patch introduces a helper that can get the queue index of a
VirtQueue. This is useful when traversing the list of VirtQueues.

Cc: Anthony Liguori <aliguori@amazon.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 hw/virtio/virtio.c         | 5 +++++
 include/hw/virtio/virtio.h | 1 +
 2 files changed, 6 insertions(+)

diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index 5e6b879..bd32518 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -725,6 +725,11 @@ hwaddr virtio_queue_get_addr(VirtIODevice *vdev, int n)
     return vdev->vq[n].pa;
 }
 
+int virtio_queue_get_index(VirtIODevice *vdev, VirtQueue *vq)
+{
+    return vq - vdev->vq;
+}
+
 void virtio_queue_set_num(VirtIODevice *vdev, int n, int num)
 {
     /* Don't allow guest to flip queue between existent and
diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
index ceab8e8..37aa9c4 100644
--- a/include/hw/virtio/virtio.h
+++ b/include/hw/virtio/virtio.h
@@ -217,6 +217,7 @@ void virtio_config_writew(VirtIODevice *vdev, uint32_t addr, uint32_t data);
 void virtio_config_writel(VirtIODevice *vdev, uint32_t addr, uint32_t data);
 void virtio_queue_set_addr(VirtIODevice *vdev, int n, hwaddr addr);
 hwaddr virtio_queue_get_addr(VirtIODevice *vdev, int n);
+int virtio_queue_get_index(VirtIODevice *vdev, VirtQueue *vq);
 void virtio_queue_set_num(VirtIODevice *vdev, int n, int num);
 int virtio_queue_get_num(VirtIODevice *vdev, int n);
 void virtio_queue_set_align(VirtIODevice *vdev, int n, int align);
-- 
2.1.0