From patchwork Fri Jan 19 22:49:59 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kui-Feng Lee X-Patchwork-Id: 13524223 X-Patchwork-Delegate: bpf@iogearbox.net Received: from mail-yw1-f173.google.com (mail-yw1-f173.google.com [209.85.128.173]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 226775914A for ; Fri, 19 Jan 2024 22:50:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.173 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705704637; cv=none; b=hJWlXsUoKEsv6gpY+eEtITA+cAvID3It2IR6YrrO2U+Sjzmi7m8AUWdz8py+Hzdya9s5ULCBdiIQtQD/L8LZfMlc9neRm8eHB+Hlb9HiAURDimDpbRD94Wo9E1PPt60eUZVTCBgGbDY3NIiR2r6p/93+BP+DV4kSZUF1bFFQQno= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705704637; c=relaxed/simple; bh=WvCkmgY55g8iBKkRmUDJdCrbZ5jw3c9lemvyV/n4qe8=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=DnuxHqlp8JMkS9BsbwlmM1xE9s++kf1KyL1VWRXeWfoI7UGM0IbrlbPAocaxXULk+7PFt5YU/relSa4fNTzL71hIZ0h+G8JC5rCSzqwxL85fnD1tRseqtodRYuykswki1M39W7V6S+qdkKnAlvR2GQ1Zl5WXM99ZZPmntwsnvnc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=gXrpJr7d; arc=none smtp.client-ip=209.85.128.173 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="gXrpJr7d" Received: by mail-yw1-f173.google.com with SMTP id 00721157ae682-5ff7a8b5e61so11982257b3.2 for ; Fri, 19 Jan 2024 14:50:35 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1705704635; x=1706309435; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=bBK9IYm2aHddPI6w+02qZMwThls/3Mjssq7z6W9IB2I=; b=gXrpJr7dmzWF/7NQek+ZAr7cfTPPkCywe11sgnhH92ZRjwXqsemwI5MuZyYs671Buw WxyrIY2gA/51KwvHCdyB+De5oWg9Oo5oUazmoSwTj8ybbSTsJL/NdJw0W39jC/5szAx6 XMS+irIi9VvCPzHbmEkjzkNEMuX1ARorzqkhkcf3v88hMouXBYOjpottoZbQWVx3jv2c nQYx2nb9Tg75bShGACpPZhQSsUHhpxrqwy9EUFfZpxXqX6Pv1+0bZHzX28R3LK99kYxa BmFiC8UQ5PSLBcXwptY/iALDKWUP+6T2/7VzYJ7tSoOAdxKu7oUGcl67xTPU9hhhmzft 3E/Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1705704635; x=1706309435; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=bBK9IYm2aHddPI6w+02qZMwThls/3Mjssq7z6W9IB2I=; b=tFJalZhJuWW6dfh6WL5/RU2jLd+9Jr+gvqtjAuh/BLwqX+59Sgbb82nCx/zpaveUfC 5BvAMC2FbbuOf9IkXK0VnBtbLuU1J0iyjJSzQQhGXThHTKFtWDWcTDILOQUyCHepUnua KwFH3PxzXa56IdfSDel2yDrQgiUULK39549oF3ZPSLpN3+W0uPmQdatXvtFVko5Z8OKz 3+CL+RbUXGBD3cmUC/mBYzIR/qiMUDpMkGQTt7XibJi89YRhRpfYdemFE2z/lo6y30Ov 5Ydv/c5wUBPxi9TY5rCHz/668EJ5C0Dlo+zItpo1ec+lICDx2lnFqWdSMOICXQyxbLyL vFlg== X-Gm-Message-State: AOJu0YwzE6YVDnCUK1oazfGF0aVto0WJfl0b3Mo0moS0Aw9nxpxFb9Bp fdXj5RC04jBelg/73POqqgLbYVfP5W6dvTAce/VPKrPp6mJ70mbBV0HNt3oF X-Google-Smtp-Source: AGHT+IFUwLLPiPWt4uvcnSzfZuK2wNRjYnphEw1d67nmUMOumP07OS3xgHLZmto+MSDSL35a43qwTA== X-Received: by 2002:a81:5cc2:0:b0:5e7:44f7:c952 with SMTP id q185-20020a815cc2000000b005e744f7c952mr568212ywb.75.1705704634835; Fri, 19 Jan 2024 14:50:34 -0800 (PST) Received: from kickker.attlocal.net ([2600:1700:6cf8:1240:b170:5bda:247f:8c47]) by smtp.gmail.com with ESMTPSA id s184-20020a819bc1000000b005ffa70964f4sm411770ywg.115.2024.01.19.14.50.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 19 Jan 2024 14:50:34 -0800 (PST) From: thinker.li@gmail.com To: bpf@vger.kernel.org, ast@kernel.org, martin.lau@linux.dev, song@kernel.org, kernel-team@meta.com, andrii@kernel.org, drosen@google.com Cc: sinquersw@gmail.com, kuifeng@meta.com, Kui-Feng Lee Subject: [PATCH bpf-next v17 08/14] bpf: pass attached BTF to the bpf_struct_ops subsystem Date: Fri, 19 Jan 2024 14:49:59 -0800 Message-Id: <20240119225005.668602-9-thinker.li@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240119225005.668602-1-thinker.li@gmail.com> References: <20240119225005.668602-1-thinker.li@gmail.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: bpf@iogearbox.net From: Kui-Feng Lee Pass the fd of a btf from the userspace to the bpf() syscall, and then convert the fd into a btf. The btf is generated from the module that defines the target BPF struct_ops type. In order to inform the kernel about the module that defines the target struct_ops type, the userspace program needs to provide a btf fd for the respective module's btf. This btf contains essential information on the types defined within the module, including the target struct_ops type. A btf fd must be provided to the kernel for struct_ops maps and for the bpf programs attached to those maps. In the case of the bpf programs, the attach_btf_obj_fd parameter is passed as part of the bpf_attr and is converted into a btf. This btf is then stored in the prog->aux->attach_btf field. Here, it just let the verifier access attach_btf directly. In the case of struct_ops maps, a btf fd is passed as value_type_btf_obj_fd of bpf_attr. The bpf_struct_ops_map_alloc() function converts the fd to a btf and stores it as st_map->btf. A flag BPF_F_VTYPE_BTF_OBJ_FD is added for map_flags to indicate that the value of value_type_btf_obj_fd is set. Signed-off-by: Kui-Feng Lee --- include/uapi/linux/bpf.h | 8 +++++ kernel/bpf/bpf_struct_ops.c | 65 ++++++++++++++++++++++++---------- kernel/bpf/syscall.c | 2 +- kernel/bpf/verifier.c | 9 +++-- tools/include/uapi/linux/bpf.h | 8 +++++ 5 files changed, 70 insertions(+), 22 deletions(-) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 8eb949b52102..adb4dc8582f7 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -1330,6 +1330,9 @@ enum { /* Get path from provided FD in BPF_OBJ_PIN/BPF_OBJ_GET commands */ BPF_F_PATH_FD = (1U << 14), + +/* Flag for value_type_btf_obj_fd, the fd is available */ + BPF_F_VTYPE_BTF_OBJ_FD = (1U << 15), }; /* Flags for BPF_PROG_QUERY. */ @@ -1403,6 +1406,11 @@ union bpf_attr { * to using 5 hash functions). */ __u64 map_extra; + + __s32 value_type_btf_obj_fd; /* fd pointing to a BTF + * type data for + * btf_vmlinux_value_type_id. + */ }; struct { /* anonymous struct used by BPF_MAP_*_ELEM commands */ diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c index 7505f515aac3..3b8d689ece5d 100644 --- a/kernel/bpf/bpf_struct_ops.c +++ b/kernel/bpf/bpf_struct_ops.c @@ -641,6 +641,7 @@ static void __bpf_struct_ops_map_free(struct bpf_map *map) bpf_jit_uncharge_modmem(PAGE_SIZE); } bpf_map_area_free(st_map->uvalue); + btf_put(st_map->btf); bpf_map_area_free(st_map); } @@ -669,7 +670,8 @@ static void bpf_struct_ops_map_free(struct bpf_map *map) static int bpf_struct_ops_map_alloc_check(union bpf_attr *attr) { if (attr->key_size != sizeof(unsigned int) || attr->max_entries != 1 || - (attr->map_flags & ~BPF_F_LINK) || !attr->btf_vmlinux_value_type_id) + (attr->map_flags & ~(BPF_F_LINK | BPF_F_VTYPE_BTF_OBJ_FD)) || + !attr->btf_vmlinux_value_type_id) return -EINVAL; return 0; } @@ -681,15 +683,36 @@ static struct bpf_map *bpf_struct_ops_map_alloc(union bpf_attr *attr) struct bpf_struct_ops_map *st_map; const struct btf_type *t, *vt; struct bpf_map *map; + struct btf *btf; int ret; - st_ops_desc = bpf_struct_ops_find_value(btf_vmlinux, attr->btf_vmlinux_value_type_id); - if (!st_ops_desc) - return ERR_PTR(-ENOTSUPP); + if (attr->map_flags & BPF_F_VTYPE_BTF_OBJ_FD) { + /* The map holds btf for its whole life time. */ + btf = btf_get_by_fd(attr->value_type_btf_obj_fd); + if (IS_ERR(btf)) + return ERR_CAST(btf); + if (!btf_is_module(btf)) { + btf_put(btf); + return ERR_PTR(-EINVAL); + } + } else { + btf = bpf_get_btf_vmlinux(); + if (IS_ERR(btf)) + return ERR_CAST(btf); + btf_get(btf); + } + + st_ops_desc = bpf_struct_ops_find_value(btf, attr->btf_vmlinux_value_type_id); + if (!st_ops_desc) { + ret = -ENOTSUPP; + goto errout; + } vt = st_ops_desc->value_type; - if (attr->value_size != vt->size) - return ERR_PTR(-EINVAL); + if (attr->value_size != vt->size) { + ret = -EINVAL; + goto errout; + } t = st_ops_desc->type; @@ -700,17 +723,17 @@ static struct bpf_map *bpf_struct_ops_map_alloc(union bpf_attr *attr) (vt->size - sizeof(struct bpf_struct_ops_value)); st_map = bpf_map_area_alloc(st_map_size, NUMA_NO_NODE); - if (!st_map) - return ERR_PTR(-ENOMEM); + if (!st_map) { + ret = -ENOMEM; + goto errout; + } st_map->st_ops_desc = st_ops_desc; map = &st_map->map; ret = bpf_jit_charge_modmem(PAGE_SIZE); - if (ret) { - __bpf_struct_ops_map_free(map); - return ERR_PTR(ret); - } + if (ret) + goto errout_free; st_map->image = arch_alloc_bpf_trampoline(PAGE_SIZE); if (!st_map->image) { @@ -719,24 +742,30 @@ static struct bpf_map *bpf_struct_ops_map_alloc(union bpf_attr *attr) * here. */ bpf_jit_uncharge_modmem(PAGE_SIZE); - __bpf_struct_ops_map_free(map); - return ERR_PTR(-ENOMEM); + ret = -ENOMEM; + goto errout_free; } st_map->uvalue = bpf_map_area_alloc(vt->size, NUMA_NO_NODE); st_map->links = bpf_map_area_alloc(btf_type_vlen(t) * sizeof(struct bpf_links *), NUMA_NO_NODE); if (!st_map->uvalue || !st_map->links) { - __bpf_struct_ops_map_free(map); - return ERR_PTR(-ENOMEM); + ret = -ENOMEM; + goto errout_free; } - - st_map->btf = btf_vmlinux; + st_map->btf = btf; mutex_init(&st_map->lock); bpf_map_init_from_attr(map, attr); return map; + +errout_free: + __bpf_struct_ops_map_free(map); +errout: + btf_put(btf); + + return ERR_PTR(ret); } static u64 bpf_struct_ops_map_mem_usage(const struct bpf_map *map) diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 05fe78ecc441..00b294ce0a61 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -1123,7 +1123,7 @@ static int map_check_btf(struct bpf_map *map, const struct btf *btf, return ret; } -#define BPF_MAP_CREATE_LAST_FIELD map_extra +#define BPF_MAP_CREATE_LAST_FIELD value_type_btf_obj_fd /* called via syscall */ static int map_create(union bpf_attr *attr) { diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 0744a1f194fa..ff41f7736618 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -20234,6 +20234,7 @@ static int check_struct_ops_btf_id(struct bpf_verifier_env *env) const struct btf_member *member; struct bpf_prog *prog = env->prog; u32 btf_id, member_idx; + struct btf *btf; const char *mname; if (!prog->gpl_compatible) { @@ -20241,8 +20242,10 @@ static int check_struct_ops_btf_id(struct bpf_verifier_env *env) return -EINVAL; } + btf = prog->aux->attach_btf ?: bpf_get_btf_vmlinux(); + btf_id = prog->aux->attach_btf_id; - st_ops_desc = bpf_struct_ops_find(btf_vmlinux, btf_id); + st_ops_desc = bpf_struct_ops_find(btf, btf_id); if (!st_ops_desc) { verbose(env, "attach_btf_id %u is not a supported struct\n", btf_id); @@ -20259,8 +20262,8 @@ static int check_struct_ops_btf_id(struct bpf_verifier_env *env) } member = &btf_type_member(t)[member_idx]; - mname = btf_name_by_offset(btf_vmlinux, member->name_off); - func_proto = btf_type_resolve_func_ptr(btf_vmlinux, member->type, + mname = btf_name_by_offset(btf, member->name_off); + func_proto = btf_type_resolve_func_ptr(btf, member->type, NULL); if (!func_proto) { verbose(env, "attach to invalid member %s(@idx %u) of struct %s\n", diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 1949d881f230..7f64865bf455 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -1330,6 +1330,9 @@ enum { /* Get path from provided FD in BPF_OBJ_PIN/BPF_OBJ_GET commands */ BPF_F_PATH_FD = (1U << 14), + +/* Flag for value_type_btf_obj_fd, the fd is available */ + BPF_F_VTYPE_BTF_OBJ_FD = (1U << 15), }; /* Flags for BPF_PROG_QUERY. */ @@ -1403,6 +1406,11 @@ union bpf_attr { * to using 5 hash functions). */ __u64 map_extra; + + __s32 value_type_btf_obj_fd; /* fd pointing to a BTF + * type data for + * btf_vmlinux_value_type_id. + */ }; struct { /* anonymous struct used by BPF_MAP_*_ELEM commands */