[PATCH v4 7/9] net/gve: add support for Rx/Tx

[Ferruh Yigit]

On 9/27/2022 8:32 AM, Junfeng Guo wrote:

> 
> Add Rx/Tx of GQI_QPL queue format and GQI_RDA queue format.
> 
> Signed-off-by: Xiaoyun Li <xiaoyun.li at intel.com>
> Signed-off-by: Junfeng Guo <junfeng.guo at intel.com>

<...>

> --- a/drivers/net/gve/gve_ethdev.c
> +++ b/drivers/net/gve/gve_ethdev.c
> @@ -583,6 +583,11 @@ gve_dev_init(struct rte_eth_dev *eth_dev)
>          if (err)
>                  return err;
> 
> +       if (gve_is_gqi(priv)) {
> +               eth_dev->rx_pkt_burst = gve_rx_burst;
> +               eth_dev->tx_pkt_burst = gve_tx_burst;
> +       }
> +

What do you think to add a log here for 'else' case, to inform user why 
datapath is not working?

<...>

> +uint16_t
> +gve_rx_burst(void *rx_queue, struct rte_mbuf **rx_pkts, uint16_t nb_pkts)
> +{
> +       volatile struct gve_rx_desc *rxr, *rxd;
> +       struct gve_rx_queue *rxq = rx_queue;
> +       uint16_t rx_id = rxq->rx_tail;
> +       struct rte_mbuf *rxe;
> +       uint16_t nb_rx, len;
> +       uint64_t addr;
> +
> +       rxr = rxq->rx_desc_ring;
> +
> +       for (nb_rx = 0; nb_rx < nb_pkts; nb_rx++) {
> +               rxd = &rxr[rx_id];
> +               if (GVE_SEQNO(rxd->flags_seq) != rxq->expected_seqno)
> +                       break;
> +
> +               if (rxd->flags_seq & GVE_RXF_ERR)
> +                       continue;
> +
> +               len = rte_be_to_cpu_16(rxd->len) - GVE_RX_PAD;
> +               rxe = rxq->sw_ring[rx_id];
> +               rxe->data_off = RTE_PKTMBUF_HEADROOM;
> +               if (rxq->is_gqi_qpl) {
> +                       addr = (uint64_t)(rxq->qpl->mz->addr) + rx_id * PAGE_SIZE + GVE_RX_PAD;
> +                       rte_memcpy((void *)((size_t)rxe->buf_addr + rxe->data_off),
> +                                  (void *)(size_t)addr, len);

Why a 'memcpy' is needed? Can't it DMA to mbuf data buffer?

> +               }
> +               rxe->nb_segs = 1;
> +               rxe->next = NULL;
> +               rxe->pkt_len = len;
> +               rxe->data_len = len;
> +               rxe->port = rxq->port_id;
> +               rxe->packet_type = 0;
> +               rxe->ol_flags = 0;
> +

As far as I can see 'sw_ring[]' filled using 'rte_pktmbuf_alloc_bulk()' 
API, which should reset mbuf fields to default values, so some of the 
assignment above can be redundant.

> +               if (rxd->flags_seq & GVE_RXF_TCP)
> +                       rxe->packet_type |= RTE_PTYPE_L4_TCP;
> +               if (rxd->flags_seq & GVE_RXF_UDP)
> +                       rxe->packet_type |= RTE_PTYPE_L4_UDP;
> +               if (rxd->flags_seq & GVE_RXF_IPV4)
> +                       rxe->packet_type |= RTE_PTYPE_L3_IPV4;
> +               if (rxd->flags_seq & GVE_RXF_IPV6)
> +                       rxe->packet_type |= RTE_PTYPE_L3_IPV6;
> +

If you are setting packet_type, it is better to implement 
'dev_supported_ptypes_get()' dev_ops too, to announce host which packet 
type parsin supporting. (+ dev_ptypes_set() dev_ops)
And later driver can announce "Packet type parsing" feature in .ini file.