Changes since PATCH v2: - Even if single buffer xdp has a hole mechanism, there will be no problem (limiting mtu and turning off GUEST GSO), so there is no need to backport "[PATCH 1/9]"; - Modify calculation of MTU for single buffer xdp in virtnet_xdp_set(); - Make truesize in mergeable mode return to literal meaning; - Add some comments for legibility; Changes since RFC: - Using headroom instead of vi->xdp_enabled to avoid re-reading in add_recvbuf_mergeable(); - Disable GRO_HW and keep linearization for single buffer xdp; - Renamed to virtnet_build_xdp_buff_mrg(); - pr_debug() to netdev_dbg(); - Adjusted the order of the patch series. Currently, virtio net only supports xdp for single-buffer packets or linearized multi-buffer packets. This patchset supports xdp for multi-buffer packets, then larger MTU can be used if xdp sets the xdp.frags. This does not affect single buffer handling. In order to build multi-buffer xdp neatly, we integrated the code into virtnet_build_xdp_buff_mrg() for xdp. The first buffer is used for prepared xdp buff, and the rest of the buffers are added to its skb_shared_info structure. This structure can also be conveniently converted during XDP_PASS to get the corresponding skb. Since virtio net uses comp pages, and bpf_xdp_frags_increase_tail() is based on the assumption of the page pool, (rxq->frag_size - skb_frag_size(frag) - skb_frag_off(frag)) is negative in most cases. So we didn't set xdp_rxq->frag_size in virtnet_open() to disable the tail increase. Heng Qi (9): virtio-net: disable the hole mechanism for xdp virtio-net: set up xdp for multi buffer packets virtio-net: update bytes calculation for xdp_frame virtio-net: build xdp_buff with multi buffers virtio-net: construct multi-buffer xdp in mergeable virtio-net: transmit the multi-buffer xdp virtio-net: build skb from multi-buffer xdp virtio-net: remove xdp related info from page_to_skb() virtio-net: support multi-buffer xdp drivers/net/virtio_net.c | 371 ++++++++++++++++++++++++++------------- 1 file changed, 250 insertions(+), 121 deletions(-) -- 2.19.1.6.gb485710b
