From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id E93FCA0C43; Fri, 22 Oct 2021 12:43:03 +0200 (CEST) Received: from [217.70.189.124] (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id AE0EA4114A; Fri, 22 Oct 2021 12:43:03 +0200 (CEST) Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) by mails.dpdk.org (Postfix) with ESMTP id 1C5C241149 for ; Fri, 22 Oct 2021 12:43:01 +0200 (CEST) X-IronPort-AV: E=McAfee;i="6200,9189,10144"; a="209382116" X-IronPort-AV: E=Sophos;i="5.87,172,1631602800"; d="scan'208";a="209382116" Received: from orsmga006.jf.intel.com ([10.7.209.51]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Oct 2021 03:43:01 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.87,172,1631602800"; d="scan'208";a="445242294" Received: from silpixa00399839.ir.intel.com (HELO localhost.localdomain) ([10.237.222.139]) by orsmga006.jf.intel.com with ESMTP; 22 Oct 2021 03:42:59 -0700 From: Ciara Loftus To: dev@dpdk.org Cc: ferruh.yigit@intel.com, Ciara Loftus , Maciej Fijalkowski Date: Fri, 22 Oct 2021 10:42:53 +0000 Message-Id: <20211022104253.31999-1-ciara.loftus@intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20211014095040.29773-1-ciara.loftus@intel.com> References: <20211014095040.29773-1-ciara.loftus@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Subject: [dpdk-dev] [PATCH v2] net/af_xdp: use bpf link for XDP programs X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" Since v0.4.0, if the underlying kernel supports it, libbpf uses 'bpf link' to manage the programs on the interfaces of the xsks. This has two repercussions for the PMD. 1. In the case where the PMD asks libbpf to load the default XDP program, the PMD no longer needs to remove it on teardown. This is because bpf link handles the unloading under the hood. 2. In the case where the PMD loads a custom program, libbpf expects this program to be linked via bpf link prior to creating the socket. This patch introduces probes for the libbpf version and kernel support for bpf link and orchestrates the loading and unloading of programs according to the capabilities of the kernel and libbpf. The libbpf version is checked with meson and pkg-config. The probe for kernel support mirrors how it is implemented in libbpf. A bpf_link is created and looked up on loopback device. If successful, bpf_link will be used for the AF_XDP netdev. Signed-off-by: Ciara Loftus Signed-off-by: Maciej Fijalkowski --- drivers/net/af_xdp/compat.h | 124 ++++++++++++++++++++++++++++ drivers/net/af_xdp/meson.build | 7 ++ drivers/net/af_xdp/rte_eth_af_xdp.c | 13 +-- 3 files changed, 139 insertions(+), 5 deletions(-) diff --git a/drivers/net/af_xdp/compat.h b/drivers/net/af_xdp/compat.h index 3880dc7dd7..1d66f5e318 100644 --- a/drivers/net/af_xdp/compat.h +++ b/drivers/net/af_xdp/compat.h @@ -2,6 +2,7 @@ * Copyright(c) 2020 Intel Corporation. */ +#include #include #include #include @@ -54,3 +55,126 @@ tx_syscall_needed(struct xsk_ring_prod *q __rte_unused) return 1; } #endif + +#ifdef RTE_LIBRTE_AF_XDP_PMD_BPF_LINK +static int link_lookup(int ifindex, int *link_fd) +{ + struct bpf_link_info link_info; + __u32 link_len; + __u32 id = 0; + int err; + int fd; + + while (true) { + err = bpf_link_get_next_id(id, &id); + if (err) { + if (errno == ENOENT) { + err = 0; + break; + } + break; + } + + fd = bpf_link_get_fd_by_id(id); + if (fd < 0) { + if (errno == ENOENT) + continue; + err = -errno; + break; + } + + link_len = sizeof(struct bpf_link_info); + memset(&link_info, 0, link_len); + err = bpf_obj_get_info_by_fd(fd, &link_info, &link_len); + if (err) { + close(fd); + break; + } + if (link_info.type == BPF_LINK_TYPE_XDP) { + if ((int)link_info.xdp.ifindex == ifindex) { + *link_fd = fd; + break; + } + } + close(fd); + } + + return err; +} + +static bool probe_bpf_link(void) +{ + DECLARE_LIBBPF_OPTS(bpf_link_create_opts, opts, + .flags = XDP_FLAGS_SKB_MODE); + struct bpf_load_program_attr prog_attr; + struct bpf_insn insns[2]; + int prog_fd, link_fd = -1; + int ifindex_lo = 1; + bool ret = false; + int err; + + err = link_lookup(ifindex_lo, &link_fd); + if (err) + return ret; + + if (link_fd >= 0) + return true; + + /* BPF_MOV64_IMM(BPF_REG_0, XDP_PASS), */ + insns[0].code = BPF_ALU64 | BPF_MOV | BPF_K; + insns[0].dst_reg = BPF_REG_0; + insns[0].imm = XDP_PASS; + + /* BPF_EXIT_INSN() */ + insns[1].code = BPF_JMP | BPF_EXIT; + + memset(&prog_attr, 0, sizeof(prog_attr)); + prog_attr.prog_type = BPF_PROG_TYPE_XDP; + prog_attr.insns = insns; + prog_attr.insns_cnt = RTE_DIM(insns); + prog_attr.license = "GPL"; + + prog_fd = bpf_load_program_xattr(&prog_attr, NULL, 0); + if (prog_fd < 0) + return ret; + + link_fd = bpf_link_create(prog_fd, ifindex_lo, BPF_XDP, &opts); + close(prog_fd); + + if (link_fd >= 0) { + ret = true; + close(link_fd); + } + + return ret; +} + +static int link_xdp_program(int if_index, int prog_fd, bool use_bpf_link) +{ + DECLARE_LIBBPF_OPTS(bpf_link_create_opts, opts); + int link_fd, ret = 0; + + if (!use_bpf_link) + return bpf_set_link_xdp_fd(if_index, prog_fd, + XDP_FLAGS_UPDATE_IF_NOEXIST); + + opts.flags = 0; + link_fd = bpf_link_create(prog_fd, if_index, BPF_XDP, &opts); + if (link_fd < 0) + ret = -1; + + return ret; +} +#else +static bool probe_bpf_link(void) +{ + return false; +} + +static int link_xdp_program(int if_index, int prog_fd, + bool use_bpf_link __rte_unused) +{ + return bpf_set_link_xdp_fd(if_index, prog_fd, + XDP_FLAGS_UPDATE_IF_NOEXIST); +} +#endif diff --git a/drivers/net/af_xdp/meson.build b/drivers/net/af_xdp/meson.build index 3ed2b29784..42dc6d69ac 100644 --- a/drivers/net/af_xdp/meson.build +++ b/drivers/net/af_xdp/meson.build @@ -16,11 +16,18 @@ endif if bpf_dep.found() and cc.has_header('bpf/xsk.h') and cc.has_header('linux/if_xdp.h') ext_deps += bpf_dep + # check for libbpf shared umem APIs bpf_ver_dep = dependency('libbpf', version : '>=0.2.0', required: false, method: 'pkg-config') if bpf_ver_dep.found() dpdk_conf.set('RTE_LIBRTE_AF_XDP_PMD_SHARED_UMEM', 1) endif + # check for libbpf bpf link support + bpf_link_dep = dependency('libbpf', version : '>=0.4.0', + required: false, method: 'pkg-config') + if bpf_link_dep.found() + dpdk_conf.set('RTE_LIBRTE_AF_XDP_PMD_BPF_LINK', 1) + endif else build = false reason = 'missing dependency, "libbpf"' diff --git a/drivers/net/af_xdp/rte_eth_af_xdp.c b/drivers/net/af_xdp/rte_eth_af_xdp.c index b362ccdcd3..3d295d9277 100644 --- a/drivers/net/af_xdp/rte_eth_af_xdp.c +++ b/drivers/net/af_xdp/rte_eth_af_xdp.c @@ -138,6 +138,7 @@ struct pmd_internals { bool shared_umem; char prog_path[PATH_MAX]; bool custom_prog_configured; + bool use_bpf_link; struct rte_ether_addr eth_addr; @@ -971,7 +972,8 @@ eth_dev_close(struct rte_eth_dev *dev) */ dev->data->mac_addrs = NULL; - remove_xdp_program(internals); + if (!internals->use_bpf_link) + remove_xdp_program(internals); if (internals->shared_umem) { struct internal_list *list; @@ -1146,7 +1148,7 @@ xsk_umem_info *xdp_umem_configure(struct pmd_internals *internals, } static int -load_custom_xdp_prog(const char *prog_path, int if_index) +load_custom_xdp_prog(const char *prog_path, int if_index, bool use_bpf_link) { int ret, prog_fd = -1; struct bpf_object *obj; @@ -1170,8 +1172,7 @@ load_custom_xdp_prog(const char *prog_path, int if_index) } /* Link the program with the given network device */ - ret = bpf_set_link_xdp_fd(if_index, prog_fd, - XDP_FLAGS_UPDATE_IF_NOEXIST); + ret = link_xdp_program(if_index, prog_fd, use_bpf_link); if (ret) { AF_XDP_LOG(ERR, "Failed to set prog fd %d on interface\n", prog_fd); @@ -1271,7 +1272,8 @@ xsk_configure(struct pmd_internals *internals, struct pkt_rx_queue *rxq, if (strnlen(internals->prog_path, PATH_MAX) && !internals->custom_prog_configured) { ret = load_custom_xdp_prog(internals->prog_path, - internals->if_index); + internals->if_index, + internals->use_bpf_link); if (ret) { AF_XDP_LOG(ERR, "Failed to load custom XDP program %s\n", internals->prog_path); @@ -1688,6 +1690,7 @@ init_internals(struct rte_vdev_device *dev, const char *if_name, strlcpy(internals->if_name, if_name, IFNAMSIZ); strlcpy(internals->prog_path, prog_path, PATH_MAX); internals->custom_prog_configured = 0; + internals->use_bpf_link = probe_bpf_link(); #ifndef ETH_AF_XDP_SHARED_UMEM if (shared_umem) { -- 2.17.1