Re: [dpdk-dev] [PATCH v3 18/21] net/virtio: add support for mergeable buffers with packed virtqueues

[Tiwei Bie <tiwei.bie@intel.com>]

On Thu, Apr 05, 2018 at 12:10:28PM +0200, Jens Freimann wrote:
> Implement support for receiving merged buffers in virtio when packed virtqueues
> are enabled.
> 
> Signed-off-by: Jens Freimann <jfreimann@redhat.com>
> ---
>  drivers/net/virtio/virtio_ethdev.c |  10 ++--
>  drivers/net/virtio/virtio_rxtx.c   | 107 +++++++++++++++++++++++++++++++++----
>  drivers/net/virtio/virtqueue.h     |   1 +
>  3 files changed, 104 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/virtio_ethdev.c
> index 7367d9c5d..a3c3376d7 100644
> --- a/drivers/net/virtio/virtio_ethdev.c
> +++ b/drivers/net/virtio/virtio_ethdev.c
> @@ -1322,15 +1322,15 @@ set_rxtx_funcs(struct rte_eth_dev *eth_dev)
>  {
>  	struct virtio_hw *hw = eth_dev->data->dev_private;
>  
> -	/* workarount for packed vqs which don't support mrg_rxbuf at this point */
> -	if (vtpci_packed_queue(hw) && vtpci_with_feature(hw, VIRTIO_NET_F_MRG_RXBUF)) {
> -		eth_dev->rx_pkt_burst = &virtio_recv_pkts_packed;
> -	} else if (hw->use_simple_rx) {
> +	if (hw->use_simple_rx) {
>  		PMD_INIT_LOG(INFO, "virtio: using simple Rx path on port %u",
>  			eth_dev->data->port_id);
>  		eth_dev->rx_pkt_burst = virtio_recv_pkts_vec;

The logic isn't right here. It means when hw->use_simple_rx
is true, virtio_recv_pkts_vec() will be selected as the rx
function for packed ring. But virtio_recv_pkts_vec() doesn't
support packed ring now.


>  	} else if (vtpci_packed_queue(hw)) {
> -		eth_dev->rx_pkt_burst = &virtio_recv_pkts_packed;
> +		if (vtpci_with_feature(hw, VIRTIO_NET_F_MRG_RXBUF))
> +			eth_dev->rx_pkt_burst = &virtio_recv_mergeable_pkts;
> +		else
> +			eth_dev->rx_pkt_burst = &virtio_recv_pkts_packed;
>  	} else if (vtpci_with_feature(hw, VIRTIO_NET_F_MRG_RXBUF)) {
>  		PMD_INIT_LOG(INFO,
>  			"virtio: using mergeable buffer Rx path on port %u",
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