[SLOF] [PATCH v1 12/27] virtio: make virtio_get_vring_used 1.0 aware

[Nikunj A Dadhania]

Signed-off-by: Nikunj A Dadhania <nikunj at linux.vnet.ibm.com>
---
 lib/libvirtio/virtio.c | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/lib/libvirtio/virtio.c b/lib/libvirtio/virtio.c
index d476a22..993e9cc 100644
--- a/lib/libvirtio/virtio.c
+++ b/lib/libvirtio/virtio.c
@@ -288,9 +288,20 @@ struct vring_avail *virtio_get_vring_avail(struct virtio_device *dev, int queue)
  */
 struct vring_used *virtio_get_vring_used(struct virtio_device *dev, int queue)
 {
-	return (void*)VQ_ALIGN((uint64_t)virtio_get_vring_avail(dev, queue)
-				  + virtio_get_qsize(dev, queue)
-				    * sizeof(struct vring_avail));
+	if (dev->type != VIRTIO_TYPE_PCI)
+		return NULL;
+	if (dev->is_modern) {
+		void *q_sel = dev->common.addr + offset_of(struct virtio_dev_common, q_select);
+		void *q_used = dev->common.addr + offset_of(struct virtio_dev_common, q_used);
+
+		ci_write_16(q_sel, cpu_to_le16(queue));
+		eieio();
+		return (void *)(virtio_read64(q_used));
+	} else {
+		return (void*)VQ_ALIGN((uint64_t)virtio_get_vring_avail(dev, queue)
+				       + virtio_get_qsize(dev, queue)
+				       * sizeof(struct vring_avail));
+	}
 }
 
 
-- 
2.5.0