[PATCH v2 1/4] virtio: Add virtio_queue_get_rings

[Edgar E. Iglesias]

From: "Edgar E. Iglesias" <edgar.igles...@amd.com>

Signed-off-by: Edgar E. Iglesias <edgar.igles...@amd.com>
---
 hw/virtio/virtio.c         | 16 ++++++++++++++++
 include/hw/virtio/virtio.h | 14 ++++++++++++++
 2 files changed, 30 insertions(+)

diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index e9d5532952..00d387ba05 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -2402,6 +2402,22 @@ void virtio_queue_set_rings(VirtIODevice *vdev, int n, 
hwaddr desc,
     virtio_init_region_cache(vdev, n);
 }
 
+void virtio_queue_get_rings(VirtIODevice *vdev, int n, hwaddr *desc,
+                            hwaddr *avail, hwaddr *used)
+{
+    assert(vdev->vq[n].vring.num);
+
+    if (desc) {
+        *desc = vdev->vq[n].vring.desc;
+    }
+    if (avail) {
+        *avail = vdev->vq[n].vring.avail;
+    }
+    if (used) {
+        *used = vdev->vq[n].vring.used;
+    }
+}
+
 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 9dd93cf965..3a24d109fb 100644
--- a/include/hw/virtio/virtio.h
+++ b/include/hw/virtio/virtio.h
@@ -361,6 +361,20 @@ int virtio_queue_get_max_num(VirtIODevice *vdev, int n);
 int virtio_get_num_queues(VirtIODevice *vdev);
 void virtio_queue_set_rings(VirtIODevice *vdev, int n, hwaddr desc,
                             hwaddr avail, hwaddr used);
+/**
+ * virtio_queue_get_rings() - read ring addresses for a virtqueue
+ * @vdev: the virtio device
+ * @n: queue index
+ * @desc: optional pointer for the descriptor ring address
+ * @avail: optional pointer for the available ring address
+ * @used: optional pointer for the used ring address
+ *
+ * Returns the ring addresses configured for queue @n. The queue must
+ * be initialized (non-zero size); passing NULL for any output argument
+ * skips that address.
+ */
+void virtio_queue_get_rings(VirtIODevice *vdev, int n, hwaddr *desc,
+                            hwaddr *avail, hwaddr *used);
 void virtio_queue_update_rings(VirtIODevice *vdev, int n);
 void virtio_init_region_cache(VirtIODevice *vdev, int n);
 void virtio_queue_set_align(VirtIODevice *vdev, int n, int align);
-- 
2.43.0