Re: [dpdk-dev] [PATCH 1/2] vhost: fix IOVA access for packed ring

[Maxime Coquelin <maxime.coquelin@redhat.com>]

On 11/6/18 7:40 AM, Tiwei Bie wrote:
> We should apply for RO access when receiving packets from the
> VM and apply for RW access when sending packets to the VM.
> 
> Fixes: a922401f35cc ("vhost: add Rx support for packed ring")
> Fixes: ae999ce49dcb ("vhost: add Tx support for packed ring")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Tiwei Bie <tiwei.bie@intel.com>
> ---
>   lib/librte_vhost/virtio_net.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
> index 8ad30c94a..5e1a1a727 100644
> --- a/lib/librte_vhost/virtio_net.c
> +++ b/lib/librte_vhost/virtio_net.c
> @@ -598,7 +598,7 @@ reserve_avail_buf_packed(struct virtio_net *dev, struct vhost_virtqueue *vq,
>   						avail_idx, &desc_count,
>   						buf_vec, &vec_idx,
>   						&buf_id, &len,
> -						VHOST_ACCESS_RO) < 0))
> +						VHOST_ACCESS_RW) < 0))
>   			return -1;
>   
>   		len = RTE_MIN(len, size);
> @@ -1503,7 +1503,7 @@ virtio_dev_tx_packed(struct virtio_net *dev, struct vhost_virtqueue *vq,
>   						vq->last_avail_idx, &desc_count,
>   						buf_vec, &nr_vec,
>   						&buf_id, &dummy_len,
> -						VHOST_ACCESS_RW) < 0))
> +						VHOST_ACCESS_RO) < 0))
>   			break;
>   
>   		if (likely(dev->dequeue_zero_copy == 0))
> 

Ouch, good catch!

Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

Thanks,
Maxime