Hi i40e-people + XDP-feature-people, The driver i40e have a XDP-redirect bug, where is it partly broken. It can transmit a redirected xdp_frame (from another driver). But broken when redirecting a xdp_frame that is received by the driver itself.
This reminds me about lacking XDP-features, as this "state" is actually "supported" (for Intel drivers), when running in 'legacy-rx' mode. This can be configured (via: 'ethtool --set-priv-flags i40e2 legacy-rx on'). When running in 'legacy-rx' mode the headroom is zero, which means that xdp_frame cannot be created as it is stored in this headroom, but an XDP-prog can still run a (DDoS) filter. (Hint grepping after xdp_redirect stats is not enough). The BUG I experience *is* that headroom is zero, but 'legacy-rx' mode is off: $ ethtool --show-priv-flags i40e2 | grep legacy-rx legacy-rx : off This is clearly a driver initialization bug as the headroom should not be zero in this configuration. Further indication that this is related to init order: If while xdp_redirect is running, I change RX-ring size (e.g. 'ethtool -G i40e2 rx 1024') then redirect starts working again. I will continue to find the offending commit... (to-be-continued) (p.s. testing on net-next on top of commit d310ec03a34e92). -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat LinkedIn: http://www.linkedin.com/in/brouer
