RE: [PATCH] net/iavf: fix mismatch between rx_pkt_burst and RX descriptor

["Zhang, Qi Z" <qi.z.zhang@intel.com>]

> -----Original Message-----
> From: Zhou, YidingX <yidingx.zhou@intel.com>
> Sent: Saturday, May 7, 2022 5:34 PM
> To: Wu, Jingjing <jingjing.wu@intel.com>; Xing, Beilei <beilei.xing@intel.com>
> Cc: Yang, Qiming <qiming.yang@intel.com>; Zhang, Qi Z
> <qi.z.zhang@intel.com>; stable@dpdk.org; Yeleswarapu, Ramamani
> <ramamani.yeleswarapu@intel.com>
> Subject: [PATCH] net/iavf: fix mismatch between rx_pkt_burst and RX
> descriptor
> 
> Some kernel drivers return the capability
> VIRTCHNL_VF_OFFLOAD_RX_FLEX_DESC when IAVF_RXDID_COMMS_OVS_1 is
> not supported. This causes PMD to use rx_pkt_burst that handles the Flex
> Receive Descriptor format, but actually configures the RXDID into
> IAVF_RXDID_LEGACY_1, then the fields of rte_mbuf Will be filled with wrong
> values in rx_pkt_burst, which will eventually lead to coredump.
> 
> This patch fixes mismatch between rx_pkt_burst and rx descriptor.
> 
> Fixes: 12b435bf8f2f ("net/iavf: support flex desc metadata extraction")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Yiding Zhou <yidingx.zhou@intel.com>
> ---
>  drivers/net/iavf/iavf_rxtx.c | 20 ++++++++++++++------
>  1 file changed, 14 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/net/iavf/iavf_rxtx.c b/drivers/net/iavf/iavf_rxtx.c index
> 345f6aeebc..69584264de 100644
> --- a/drivers/net/iavf/iavf_rxtx.c
> +++ b/drivers/net/iavf/iavf_rxtx.c
> @@ -2908,6 +2908,18 @@ iavf_set_rx_function(struct rte_eth_dev *dev)
>  	bool use_avx512 = false;
>  	bool use_flex = false;
> 
> +	if (vf->vf_res->vf_cap_flags & VIRTCHNL_VF_OFFLOAD_RX_FLEX_DESC)
> +		use_flex = true;

No need this check, we can init use_flex as true;

> +
> +	for (i = 0; i < dev->data->nb_rx_queues; i++) {
> +		rxq = dev->data->rx_queues[i];
> +		if (rxq->rxdid <= IAVF_RXDID_LEGACY_1 ||
> +			!(vf->supported_rxdid & BIT(rxq->rxdid))) {

Check if rxq->rxdid is in supported list is not necessary, this has been  guaranteed when we set it.

Also its better to print some warning message here,  if we saw some rxq->rxdid is flex and some rxq->rxdid is legacy as we have to set rx_burst as legacy for all , this is something not be expected by user