[PATCH] net/ixgbevf: fix RSS init for x550 nics

[Medvedkin, Vladimir]

On 15/02/2024 13:31, edwin.brossette at 6wind.com wrote:
> From: Edwin Brossette <edwin.brossette at 6wind.com>
>
> Different Intel nics with the igxbe pmd do not handle RSS in the same
> way when working with virtualization. While some nics like Intel 82599ES
> only have a single RSS table in the device and leave all rss features to
> be handled by the pf, some other nics like x550 let the vf handle RSS
> features. This can lead to different behavior when rss is enabled
> depending on the model of nic used.
>
> In particular, it occurred that ixgbevf_dev_rx_init() do not initiate
> rss parameters at device init, even if the multi-queue mode option is
> set in the device configuration (ie: RTE_ETH_MQ_RX_RSS is set). Note
> that this issue went unnoticed until now, probably because some nics do
> not really have support for RSS in virtualization mode.
>
> Thus, depending on the nic used, we can we find ourselves in a situation
> where RSS is not configured despite being enabled. This will cause
> serious performance issues because the RSS reta will be fully zeroed,
> causing all packets to go only in the first queue and leaving all the
> others empty.
>
> By looking at ixgbe_reta_size_get(), we can see that only X550 nic
> models have a non zero reta size set in vf mode. Thus add a call to
> ixgbe_rss_configure() for these cards in ixgbevf_dev_rx_init() if the
> option to enable RSS is set.
>
> Fixes: f4d1598ee14f ("ixgbevf: support RSS config on x550")
> Signed-off-by: Edwin Brossette <edwin.brossette at 6wind.com>
> ---
>   drivers/net/ixgbe/ixgbe_rxtx.c | 19 +++++++++++++++++++
>   1 file changed, 19 insertions(+)
>
> diff --git a/drivers/net/ixgbe/ixgbe_rxtx.c b/drivers/net/ixgbe/ixgbe_rxtx.c
> index 537aa2f68de8..0aa968f7e258 100644
> --- a/drivers/net/ixgbe/ixgbe_rxtx.c
> +++ b/drivers/net/ixgbe/ixgbe_rxtx.c
> @@ -5873,6 +5873,25 @@ ixgbevf_dev_rx_init(struct rte_eth_dev *dev)
>   		IXGBE_PSRTYPE_RQPL_SHIFT;
>   	IXGBE_WRITE_REG(hw, IXGBE_VFPSRTYPE, psrtype);
>   
> +	/* Initialize the rss for x550_vf cards if enabled */
> +	switch (hw->mac.type) {
> +	case ixgbe_mac_X550_vf:
> +	case ixgbe_mac_X550EM_x_vf:
> +	case ixgbe_mac_X550EM_a_vf:
> +		switch (dev->data->dev_conf.rxmode.mq_mode) {
> +		case RTE_ETH_MQ_RX_RSS:
> +		case RTE_ETH_MQ_RX_DCB_RSS:
> +		case RTE_ETH_MQ_RX_VMDQ_RSS:
> +			ixgbe_rss_configure(dev);
> +			break;
> +		default:
> +			break;
> +		}
> +		break;
> +	default:
> +		break;
> +	}
> +
>   	ixgbe_set_rx_function(dev);
>   
>   	return 0;
Acked-by: Vladimir Medvedkin <vladimir.medvedkin at intel.com>

-- 
Regards,
Vladimir