On 2018/07/24 10:56, Toshiaki Makita wrote: > On 2018/07/24 9:27, Jakub Kicinski wrote: >> On Mon, 23 Jul 2018 00:13:03 +0900, Toshiaki Makita wrote: >>> From: Toshiaki Makita <makita.toshi...@lab.ntt.co.jp> >>> >>> All oversized packets including GSO packets are dropped if XDP is >>> enabled on receiver side, so don't send such packets from peer. >>> >>> Drop TSO and SCTP fragmentation features so that veth devices themselves >>> segment packets with XDP enabled. Also cap MTU accordingly. >>> >>> Signed-off-by: Toshiaki Makita <makita.toshi...@lab.ntt.co.jp> >> >> Is there any precedence for fixing up features and MTU like this? Most >> drivers just refuse to install the program if settings are incompatible. > > I don't know any precedence. I can refuse the program on installing it > when features and MTU are not appropriate. Is it preferred? > Note that with current implementation wanted_features are not touched so > features will be restored when the XDP program is removed. MTU will not > be restored though, as I do not remember the original MTU.
I just recalled that virtio_net used to refused XDP when guest offload features are incompatible but now it dynamically fixup them on installing an XDP program. https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=3f93522ffab2d46a36b57adf324a54e674fc9536 -- Toshiaki Makita
