Re: [dpdk-dev] [PATCH] net/iavf: fix virtual channel RSS command error handling

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

> -----Original Message-----
> From: dev <dev-bounces@dpdk.org> On Behalf Of Alvin Zhang
> Sent: Wednesday, July 21, 2021 2:32 PM
> To: Xing, Beilei <beilei.xing@intel.com>
> Cc: dev@dpdk.org; Zhang, AlvinX <alvinx.zhang@intel.com>; stable@dpdk.org
> Subject: [dpdk-dev] [PATCH] net/iavf: fix virtual channel RSS command error
> handling
> 
> Kernel PF may not respond to virtual channel commands
> VIRTCHNL_OP_GET_RSS_HENA_CAPS and VIRTCHNL_OP_SET_RSS_HENA,
> which will cause VF to fail to start.
> 
> RSS offload type configuration is not a necessary feature for VF, so in order to
> improve VF compatibility, in this patch the PMD will ignore the error result of
> above two commands and will print warnings instead.
> 
> Fixes: 5a038d19962d ("net/iavf: fix RSS configuration on i40e VF")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Alvin Zhang <alvinx.zhang@intel.com>
> ---
>  drivers/net/iavf/iavf_ethdev.c | 26 ++++++++++++++------------
>  1 file changed, 14 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/net/iavf/iavf_ethdev.c b/drivers/net/iavf/iavf_ethdev.c index
> 41382c6..162f55d 100644
> --- a/drivers/net/iavf/iavf_ethdev.c
> +++ b/drivers/net/iavf/iavf_ethdev.c
> @@ -259,7 +259,7 @@ struct rte_iavf_xstats_name_off {
>  	return err;
>  }
> 
> -static int
> +static void
>  iavf_config_rss_hf(struct iavf_adapter *adapter, uint64_t rss_hf)  {
>  	static const uint64_t map_hena_rss[] = { @@ -319,8 +319,12 @@ struct
> rte_iavf_xstats_name_off {
>  	int ret;
> 
>  	ret = iavf_get_hena_caps(adapter, &caps);
> -	if (ret)
> -		return ret;
> +	if (ret) {
> +		PMD_DRV_LOG(WARNING,
> +			    "fail to get supported RSS caps, lack PF support");

This is misleading, the failure reason is not necessary be "lack PF support', it could be any other reason
So better just print the error code here, or simply ignore if a meaningful failure message will already be printed inside iavf_get_hena_caps.

> +		return;
> +	}
> +
>  	/**
>  	 * ETH_RSS_IPV4 and ETH_RSS_IPV6 can be considered as 2
>  	 * generalizations of all other IPv4 and IPv6 RSS types.
> @@ -343,8 +347,11 @@ struct rte_iavf_xstats_name_off {
>  	}
> 
>  	ret = iavf_set_hena(adapter, hena);
> -	if (ret)
> -		return ret;
> +	if (ret) {
> +		PMD_DRV_LOG(WARNING,
> +			    "fail to clean existing RSS, lack PF support");

Actually this is not the case to "clean" but "overwrite", also the "lack PF support" should be refined base on previous comments.

> +		return;
> +	}
> 
>  	if (valid_rss_hf & ipv4_rss)
>  		valid_rss_hf |= rss_hf & ETH_RSS_IPV4; @@ -357,7 +364,6 @@
> struct rte_iavf_xstats_name_off {
>  			    rss_hf & ~valid_rss_hf);
> 
>  	vf->rss_hf = valid_rss_hf;
> -	return 0;
>  }
> 
>  static int
> @@ -409,9 +415,7 @@ struct rte_iavf_xstats_name_off {
>  			return ret;
>  		}
>  	} else {
> -		ret = iavf_config_rss_hf(adapter, rss_conf->rss_hf);
> -		if (ret != -ENOTSUP)
> -			return ret;
> +		iavf_config_rss_hf(adapter, rss_conf->rss_hf);
>  	}
> 
>  	return 0;
> @@ -1400,9 +1404,7 @@ static int iavf_config_rx_queues_irqs(struct
> rte_eth_dev *dev,
>  			return ret;
>  		}
>  	} else {
> -		ret = iavf_config_rss_hf(adapter, rss_conf->rss_hf);
> -		if (ret != -ENOTSUP)
> -			return ret;
> +		iavf_config_rss_hf(adapter, rss_conf->rss_hf);
>  	}
> 
>  	return 0;
> --
> 1.8.3.1