[Qemu-devel] [PATCH v2 12/15] virtio: add vhost-net migration for packed ring

[wexu@redhat.com]

From: Wei Xu <wexu@redhat.com>

Signed-off-by: Wei Xu <wexu@redhat.com>
---
 hw/virtio/virtio.c | 27 ++++++++++++++++++++++++---
 1 file changed, 24 insertions(+), 3 deletions(-)

diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index 722a4fd..0cb912e 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -2991,17 +2991,34 @@ hwaddr virtio_queue_get_used_size(VirtIODevice *vdev, int n)
 
 uint16_t virtio_queue_get_last_avail_idx(VirtIODevice *vdev, int n)
 {
-    return vdev->vq[n].last_avail_idx;
+    uint16_t idx;
+
+    if (virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) {
+        idx = vdev->vq[n].last_avail_idx;
+        idx |= ((int)vdev->vq[n].avail_wrap_counter) << 15;
+    } else {
+        idx = (int)vdev->vq[n].last_avail_idx;
+    }
+    return idx;
 }
 
 void virtio_queue_set_last_avail_idx(VirtIODevice *vdev, int n, uint16_t idx)
 {
-    vdev->vq[n].last_avail_idx = idx;
-    vdev->vq[n].shadow_avail_idx = idx;
+    if (virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) {
+        vdev->vq[n].last_avail_idx = idx & 0x7fff;
+        vdev->vq[n].avail_wrap_counter = !!(idx & 0x8000);
+    } else {
+        vdev->vq[n].last_avail_idx = idx;
+        vdev->vq[n].shadow_avail_idx = idx;
+    }
 }
 
 void virtio_queue_restore_last_avail_idx(VirtIODevice *vdev, int n)
 {
+    if (virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) {
+        return;
+    }
+
     rcu_read_lock();
     if (vdev->vq[n].vring.desc) {
         vdev->vq[n].last_avail_idx = vring_used_idx(&vdev->vq[n]);
@@ -3012,6 +3029,10 @@ void virtio_queue_restore_last_avail_idx(VirtIODevice *vdev, int n)
 
 void virtio_queue_update_used_idx(VirtIODevice *vdev, int n)
 {
+    if (virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) {
+        return;
+    }
+
     rcu_read_lock();
     if (vdev->vq[n].vring.desc) {
         vdev->vq[n].used_idx = vring_used_idx(&vdev->vq[n]);
-- 
1.8.3.1