From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B0B18C433F5 for ; Fri, 8 Oct 2021 12:50:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8A84D61027 for ; Fri, 8 Oct 2021 12:50:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230216AbhJHMwv (ORCPT ); Fri, 8 Oct 2021 08:52:51 -0400 Received: from mail.kernel.org ([198.145.29.99]:49516 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230204AbhJHMwu (ORCPT ); Fri, 8 Oct 2021 08:52:50 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 7E70A60FE8; Fri, 8 Oct 2021 12:50:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1633697455; bh=NyRmFPsBQ6EoiE6+9jZf9l24RAcI6PiK9XyiDUNC7k4=; h=From:To:Cc:Subject:Date:From; b=MDYnzJGR1Fp3iWP9M+IfkwveETedXliChQSjOKDz6XIi4uHZ9R63WwznyVHlPbvKK t8Xv1Zf7ntc4VQUfPYRUYgZDqMqynAHBl4Hh5QQ7apzRjZgW+xXdj04UNmCF2SstqC XhFlZSy48VjZHuf4REj7a5mroWXg5bq3f12tskeHh/cZip7ZVkE346JGf5WVPcOpUC vG43aruf47aOjSz+1o+InvUdkWf3R6jdizas9azhorrwbSwlA2gzj+loum6qDtp09E oCPOJpRD5wN4pJDG8KlGCTu192ErpawjEyf5/3SpCQou5yusWjCB1fqqjtFQMTqdlg VqIcJ+tBmkJDg== From: Lorenzo Bianconi To: bpf@vger.kernel.org, netdev@vger.kernel.org Cc: lorenzo.bianconi@redhat.com, davem@davemloft.net, kuba@kernel.org, ast@kernel.org, daniel@iogearbox.net, shayagr@amazon.com, john.fastabend@gmail.com, dsahern@kernel.org, brouer@redhat.com, echaudro@redhat.com, jasowang@redhat.com, alexander.duyck@gmail.com, saeed@kernel.org, maciej.fijalkowski@intel.com, magnus.karlsson@intel.com, tirthendu.sarkar@intel.com, toke@redhat.com Subject: [PATCH v15 bpf-next 00/18] mvneta: introduce XDP multi-buffer support Date: Fri, 8 Oct 2021 14:49:38 +0200 Message-Id: X-Mailer: git-send-email 2.31.1 MIME-Version: 1.0 Content-Type: text/plain; charset=y Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org This series introduce XDP multi-buffer support. The mvneta driver is the first to support these new "non-linear" xdp_{buff,frame}. Reviewers please focus on how these new types of xdp_{buff,frame} packets traverse the different layers and the layout design. It is on purpose that BPF-helpers are kept simple, as we don't want to expose the internal layout to allow later changes. The main idea for the new multi-buffer layout is to reuse the same structure used for non-linear SKB. This rely on the "skb_shared_info" struct at the end of the first buffer to link together subsequent buffers. Keeping the layout compatible with SKBs is also done to ease and speedup creating a SKB from an xdp_{buff,frame}. Converting xdp_frame to SKB and deliver it to the network stack is shown in patch 05/18 (e.g. cpumaps). A multi-buffer bit (mb) has been introduced in the flags field of xdp_{buff,frame} structure to notify the bpf/network layer if this is a xdp multi-buffer frame (mb = 1) or not (mb = 0). The mb bit will be set by a xdp multi-buffer capable driver only for non-linear frames maintaining the capability to receive linear frames without any extra cost since the skb_shared_info structure at the end of the first buffer will be initialized only if mb is set. Moreover the flags field in xdp_{buff,frame} will be reused even for xdp rx csum offloading in future series. Typical use cases for this series are: - Jumbo-frames - Packet header split (please see Google’s use-case @ NetDevConf 0x14, [0]) - TSO/GRO for XDP_REDIRECT The three following ebpf helpers (and related selftests) has been introduced: - bpf_xdp_load_bytes: This helper is provided as an easy way to load data from a xdp buffer. It can be used to load len bytes from offset from the frame associated to xdp_md, into the buffer pointed by buf. - bpf_xdp_store_bytes: Store len bytes from buffer buf into the frame associated to xdp_md, at offset. - bpf_xdp_get_buff_len: Return the total frame size (linear + paged parts) bpf_xdp_adjust_tail and bpf_xdp_copy helpers have been modified to take into account xdp multi-buff frames. Moreover, similar to skb_header_pointer, introduce bpf_xdp_pointer utility routine to return a pointer to a given position in the xdp_buff if the requested area (offset + len) is contained in a contiguous memory area otherwise it will be copied in a bounce buffer provided by the caller. A multi-buffer enabled NIC may receive XDP frames with multiple frags. If a BPF program does not understand mb layouts its possible to contrive a BPF program that incorrectly views data_end as the end of data when there is more data in the payload. Note helpers will generally due the correct thing, for example perf_output will consume entire payload. But, it is still possible some programs could do the wrong thing even if in an edge case. Although we expect most BPF programs not to be impacted we can't rule out, you've been warned. More info about the main idea behind this approach can be found here [1][2]. Changes since v14: - intrudce bpf_xdp_pointer utility routine and bpf_xdp_load_bytes/bpf_xdp_store_bytes helpers - drop bpf_xdp_adjust_data helper - drop xdp_frags_truesize in skb_shared_info - explode bpf_xdp_mb_adjust_tail in bpf_xdp_mb_increase_tail and bpf_xdp_mb_shrink_tail Changes since v13: - use u32 for xdp_buff/xdp_frame flags field - rename xdp_frags_tsize in xdp_frags_truesize - fixed comments Changes since v12: - fix bpf_xdp_adjust_data helper for single-buffer use case - return -EFAULT in bpf_xdp_adjust_{head,tail} in case the data pointers are not properly reset - collect ACKs from John Changes since v11: - add missing static to bpf_xdp_get_buff_len_proto structure - fix bpf_xdp_adjust_data helper when offset is smaller than linear area length. Changes since v10: - move xdp->data to the requested payload offset instead of to the beginning of the fragment in bpf_xdp_adjust_data() Changes since v9: - introduce bpf_xdp_adjust_data helper and related selftest - add xdp_frags_size and xdp_frags_tsize fields in skb_shared_info - introduce xdp_update_skb_shared_info utility routine in ordere to not reset frags array in skb_shared_info converting from a xdp_buff/xdp_frame to a skb - simplify bpf_xdp_copy routine Changes since v8: - add proper dma unmapping if XDP_TX fails on mvneta for a xdp multi-buff - switch back to skb_shared_info implementation from previous xdp_shared_info one - avoid using a bietfield in xdp_buff/xdp_frame since it introduces performance regressions. Tested now on 10G NIC (ixgbe) to verify there are no performance penalties for regular codebase - add bpf_xdp_get_buff_len helper and remove frame_length field in xdp ctx - add data_len field in skb_shared_info struct - introduce XDP_FLAGS_FRAGS_PF_MEMALLOC flag Changes since v7: - rebase on top of bpf-next - fix sparse warnings - improve comments for frame_length in include/net/xdp.h Changes since v6: - the main difference respect to previous versions is the new approach proposed by Eelco to pass full length of the packet to eBPF layer in XDP context - reintroduce multi-buff support to eBPF kself-tests - reintroduce multi-buff support to bpf_xdp_adjust_tail helper - introduce multi-buffer support to bpf_xdp_copy helper - rebase on top of bpf-next Changes since v5: - rebase on top of bpf-next - initialize mb bit in xdp_init_buff() and drop per-driver initialization - drop xdp->mb initialization in xdp_convert_zc_to_xdp_frame() - postpone introduction of frame_length field in XDP ctx to another series - minor changes Changes since v4: - rebase ontop of bpf-next - introduce xdp_shared_info to build xdp multi-buff instead of using the skb_shared_info struct - introduce frame_length in xdp ctx - drop previous bpf helpers - fix bpf_xdp_adjust_tail for xdp multi-buff - introduce xdp multi-buff self-tests for bpf_xdp_adjust_tail - fix xdp_return_frame_bulk for xdp multi-buff Changes since v3: - rebase ontop of bpf-next - add patch 10/13 to copy back paged data from a xdp multi-buff frame to userspace buffer for xdp multi-buff selftests Changes since v2: - add throughput measurements - drop bpf_xdp_adjust_mb_header bpf helper - introduce selftest for xdp multibuffer - addressed comments on bpf_xdp_get_frags_count - introduce xdp multi-buff support to cpumaps Changes since v1: - Fix use-after-free in xdp_return_{buff/frame} - Introduce bpf helpers - Introduce xdp_mb sample program - access skb_shared_info->nr_frags only on the last fragment Changes since RFC: - squash multi-buffer bit initialization in a single patch - add mvneta non-linear XDP buff support for tx side [0] https://netdevconf.info/0x14/session.html?talk-the-path-to-tcp-4k-mtu-and-rx-zerocopy [1] https://github.com/xdp-project/xdp-project/blob/master/areas/core/xdp-multi-buffer01-design.org [2] https://netdevconf.info/0x14/session.html?tutorial-add-XDP-support-to-a-NIC-driver (XDPmulti-buffers section) Eelco Chaudron (3): bpf: add multi-buff support to the bpf_xdp_adjust_tail() API bpf: add multi-buffer support to xdp copy helpers bpf: update xdp_adjust_tail selftest to include multi-buffer Lorenzo Bianconi (15): net: skbuff: add size metadata to skb_shared_info for xdp xdp: introduce flags field in xdp_buff/xdp_frame net: mvneta: update mb bit before passing the xdp buffer to eBPF layer net: mvneta: simplify mvneta_swbm_add_rx_fragment management net: xdp: add xdp_update_skb_shared_info utility routine net: marvell: rely on xdp_update_skb_shared_info utility routine xdp: add multi-buff support to xdp_return_{buff/frame} net: mvneta: add multi buffer support to XDP_TX net: mvneta: enable jumbo frames for XDP bpf: introduce bpf_xdp_get_buff_len helper bpf: move user_size out of bpf_test_init bpf: introduce multibuff support to bpf_prog_test_run_xdp() bpf: test_run: add xdp_shared_info pointer in bpf_test_finish signature net: xdp: introduce bpf_xdp_pointer utility routine bpf: introduce bpf_xdp_{load,store}_bytes selftest drivers/net/ethernet/marvell/mvneta.c | 198 ++++++------ include/linux/skbuff.h | 1 + include/net/xdp.h | 80 ++++- include/uapi/linux/bpf.h | 25 ++ kernel/trace/bpf_trace.c | 3 + net/bpf/test_run.c | 111 +++++-- net/core/filter.c | 283 +++++++++++++++++- net/core/xdp.c | 71 ++++- tools/include/uapi/linux/bpf.h | 25 ++ .../bpf/prog_tests/xdp_adjust_frags.c | 81 +++++ .../bpf/prog_tests/xdp_adjust_tail.c | 118 ++++++++ .../selftests/bpf/prog_tests/xdp_bpf2bpf.c | 151 +++++++--- .../bpf/progs/test_xdp_adjust_tail_grow.c | 10 +- .../bpf/progs/test_xdp_adjust_tail_shrink.c | 32 +- .../selftests/bpf/progs/test_xdp_bpf2bpf.c | 2 +- .../bpf/progs/test_xdp_update_frags.c | 42 +++ 16 files changed, 1068 insertions(+), 165 deletions(-) create mode 100644 tools/testing/selftests/bpf/prog_tests/xdp_adjust_frags.c create mode 100644 tools/testing/selftests/bpf/progs/test_xdp_update_frags.c -- 2.31.1