On Fri, Nov 20, 2020 at 07:50:58PM +0100, Eugenio Pérez wrote:
> @@ -1028,6 +1061,7 @@ static int vhost_sw_live_migration_start(struct vhost_dev *dev)
>  
>      for (idx = 0; idx < dev->nvqs; ++idx) {
>          struct vhost_virtqueue *vq = &dev->vqs[idx];
> +        unsigned num = virtio_queue_get_num(dev->vdev, idx);
>          struct vhost_vring_addr addr = {
>              .index = idx,
>          };
> @@ -1044,6 +1078,12 @@ static int vhost_sw_live_migration_start(struct vhost_dev *dev)
>          r = dev->vhost_ops->vhost_set_vring_addr(dev, &addr);
>          assert(r == 0);
>  
> +        r = vhost_backend_update_device_iotlb(dev, addr.used_user_addr,
> +                                              addr.used_user_addr,
> +                                              sizeof(vring_used_elem_t) * num,
> +                                              IOMMU_RW);

I don't remember seeing iotlb setup for the rest of the vring or guest
memory. Maybe this should go into a single patch so it's easy to review
the iova space layout.