[SLOF] [PATCH v1 11/27] virtio: make virtio_get_vring_avail 1.0 aware

[Nikunj A Dadhania]

Signed-off-by: Nikunj A Dadhania <nikunj at linux.vnet.ibm.com>
---
 lib/libvirtio/virtio.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/lib/libvirtio/virtio.c b/lib/libvirtio/virtio.c
index f95e86b..d476a22 100644
--- a/lib/libvirtio/virtio.c
+++ b/lib/libvirtio/virtio.c
@@ -263,8 +263,20 @@ struct vring_desc *virtio_get_vring_desc(struct virtio_device *dev, int queue)
  */
 struct vring_avail *virtio_get_vring_avail(struct virtio_device *dev, int queue)
 {
-	return (void*)((uint64_t)virtio_get_vring_desc(dev, queue)
-			+ virtio_get_qsize(dev, queue) * sizeof(struct vring_desc));
+	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_avail = dev->common.addr + offset_of(struct virtio_dev_common, q_avail);
+
+		ci_write_16(q_sel, cpu_to_le16(queue));
+		eieio();
+		return (void *)(virtio_read64(q_avail));
+	}
+	else {
+		return (void*)((uint64_t)virtio_get_vring_desc(dev, queue) +
+			       virtio_get_qsize(dev, queue) * sizeof(struct vring_desc));
+	}
 }
 
 
-- 
2.5.0