From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-178.mta0.migadu.com (out-178.mta0.migadu.com [91.218.175.178]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D4FC72080C4 for ; Thu, 17 Jul 2025 19:38:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.178 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752781114; cv=none; b=ZjsXhzH5Ju+8Cik0DcUlu+Ed12TxPbq6KC1l7rH7tN6odxnXV6GqBu4vjHKFLMA9Ew+kIEPOYx7Bo9KJRBz7RXefkF0EdM2IwPP2pdIsaJjAPZMXJqattkw0XK9B1nMNlDlFwvFok4tczOZzhLUeqChf4oaOq5zp0//3A2WHMZY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752781114; c=relaxed/simple; bh=9+ntgFbnjMrZYS43QiRIyaCBMJXMwk1nTGlbjO37xSo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=uaXFDcB/0UbrDMntLqcADaRqdb3+fASp/UnoXkohtDdUeduYO5cYS7ztUhroFWxQp6OkS4urHOri5kZDslkFa4tFWfwk30/fdSVu5WUEhyiP8jxrzsaU7LYEHXjfkfgQKmXVzrWn6NUAE9efoTrVOsiE5zJMapJYff7XzuzzdCs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=LOpnNdOb; arc=none smtp.client-ip=91.218.175.178 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="LOpnNdOb" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1752781110; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=+hKu5B+A9IL9jJSouU/bizbztY2SwsJzp4YGIWTPaOw=; b=LOpnNdObA3Mz1kqoy6DL3N8ybbEjMx1pS9w9ke9SQctJqIC8qe0Z4U6IsN/FJQIspKdybD fkLkyZR3L0ingNKU5utnpgigf9ZQXafEyBfts9qzMpEKjrh5ZowSYAPY8a9pVVzw0ky2MJ L4cVTDEvsRWMP26vh3Kk1EN0VrkoHQE= From: Leon Hwang To: bpf@vger.kernel.org Cc: ast@kernel.org, andrii@kernel.org, daniel@iogearbox.net, yonghong.song@linux.dev, song@kernel.org, eddyz87@gmail.com, dxu@dxuuu.xyz, deso@posteo.net, leon.hwang@linux.dev, kernel-patches-bot@fb.com Subject: [PATCH bpf-next 2/3] bpf, libbpf: Support BPF_F_CPU for percpu_array map Date: Fri, 18 Jul 2025 03:37:55 +0800 Message-ID: <20250717193756.37153-3-leon.hwang@linux.dev> In-Reply-To: <20250717193756.37153-1-leon.hwang@linux.dev> References: <20250717193756.37153-1-leon.hwang@linux.dev> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT This patch adds libbpf support for the BPF_F_CPU flag in percpu_array maps, introducing the following APIs: 1. bpf_map_update_elem_opts(): update with struct bpf_map_update_elem_opts 2. bpf_map_lookup_elem_opts(): lookup with struct bpf_map_lookup_elem_opts 3. bpf_map__update_elem_opts(): high-level wrapper with input validation 4. bpf_map__lookup_elem_opts(): high-level wrapper with input validation Behavior: * If opts->cpu == (u32)~0, the update is applied to all CPUs. * Otherwise, it applies only to the specified CPU. * Lookup APIs retrieve values from the target CPU when BPF_F_CPU is used. Signed-off-by: Leon Hwang --- tools/lib/bpf/bpf.c | 23 ++++++++++++++ tools/lib/bpf/bpf.h | 36 +++++++++++++++++++++- tools/lib/bpf/libbpf.c | 56 +++++++++++++++++++++++++++++++---- tools/lib/bpf/libbpf.h | 53 ++++++++++++++++++++++++++++----- tools/lib/bpf/libbpf.map | 5 ++++ tools/lib/bpf/libbpf_common.h | 14 +++++++++ 6 files changed, 173 insertions(+), 14 deletions(-) diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c index ab40dbf9f020..8061093d84f9 100644 --- a/tools/lib/bpf/bpf.c +++ b/tools/lib/bpf/bpf.c @@ -402,6 +402,17 @@ int bpf_map_update_elem(int fd, const void *key, const void *value, return libbpf_err_errno(ret); } +int bpf_map_update_elem_opts(int fd, const void *key, const void *value, + const struct bpf_map_update_elem_opts *opts) +{ + __u64 flags; + __u32 cpu; + + cpu = OPTS_GET(opts, cpu, 0); + flags = ((__u64) cpu) << 32 | OPTS_GET(opts, flags, 0); + return bpf_map_update_elem(fd, key, value, flags); +} + int bpf_map_lookup_elem(int fd, const void *key, void *value) { const size_t attr_sz = offsetofend(union bpf_attr, flags); @@ -433,6 +444,17 @@ int bpf_map_lookup_elem_flags(int fd, const void *key, void *value, __u64 flags) return libbpf_err_errno(ret); } +int bpf_map_lookup_elem_opts(int fd, const void *key, void *value, + const struct bpf_map_lookup_elem_opts *opts) +{ + __u64 flags; + __u32 cpu; + + cpu = OPTS_GET(opts, cpu, 0); + flags = ((__u64) cpu) << 32 | OPTS_GET(opts, flags, 0); + return bpf_map_lookup_elem_flags(fd, key, value, flags); +} + int bpf_map_lookup_and_delete_elem(int fd, const void *key, void *value) { const size_t attr_sz = offsetofend(union bpf_attr, flags); @@ -542,6 +564,7 @@ static int bpf_map_batch_common(int cmd, int fd, void *in_batch, attr.batch.count = *count; attr.batch.elem_flags = OPTS_GET(opts, elem_flags, 0); attr.batch.flags = OPTS_GET(opts, flags, 0); + attr.batch.cpu = OPTS_GET(opts, cpu, 0); ret = sys_bpf(cmd, &attr, attr_sz); *count = attr.batch.count; diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h index 7252150e7ad3..d0ab18b50294 100644 --- a/tools/lib/bpf/bpf.h +++ b/tools/lib/bpf/bpf.h @@ -163,12 +163,42 @@ LIBBPF_API int bpf_map_delete_elem_flags(int fd, const void *key, __u64 flags); LIBBPF_API int bpf_map_get_next_key(int fd, const void *key, void *next_key); LIBBPF_API int bpf_map_freeze(int fd); +/** + * @brief **bpf_map_update_elem_opts** allows for updating map with options. + * + * @param fd BPF map file descriptor + * @param key pointer to key + * @param value pointer to value + * @param opts options for configuring the way to update map + * @return 0, on success; negative error code, otherwise (errno is also set to + * the error code) + */ +LIBBPF_API int bpf_map_update_elem_opts(int fd, const void *key, const void *value, + const struct bpf_map_update_elem_opts *opts); + +/** + * @brief **bpf_map_lookup_elem_opts** allows for looking up the value with + * options. + * + * @param fd BPF map file descriptor + * @param key pointer to key + * @param value pointer to value + * @param opts options for configuring the way to lookup map + * @return 0, on success; negative error code, otherwise (errno is also set to + * the error code) + */ +LIBBPF_API int bpf_map_lookup_elem_opts(int fd, const void *key, void *value, + const struct bpf_map_lookup_elem_opts *opts); + + struct bpf_map_batch_opts { size_t sz; /* size of this struct for forward/backward compatibility */ __u64 elem_flags; __u64 flags; + __u32 cpu; + size_t:0; }; -#define bpf_map_batch_opts__last_field flags +#define bpf_map_batch_opts__last_field cpu /** @@ -286,6 +316,10 @@ LIBBPF_API int bpf_map_lookup_and_delete_batch(int fd, void *in_batch, * Update spin_lock-ed map elements. This must be * specified if the map value contains a spinlock. * + * **BPF_F_CPU** + * As for percpu map, update value across all CPUs if **opts->cpu** is + * (__u32)~0, or on specified CPU otherwise. + * * @param fd BPF map file descriptor * @param keys pointer to an array of *count* keys * @param values pointer to an array of *count* values diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index aee36402f0a3..35faedef6ab4 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -10582,7 +10582,8 @@ bpf_object__find_map_fd_by_name(const struct bpf_object *obj, const char *name) } static int validate_map_op(const struct bpf_map *map, size_t key_sz, - size_t value_sz, bool check_value_sz) + size_t value_sz, bool check_value_sz, __u64 flags, + __u32 cpu) { if (!map_is_created(map)) /* map is not yet created */ return -ENOENT; @@ -10601,6 +10602,19 @@ static int validate_map_op(const struct bpf_map *map, size_t key_sz, if (!check_value_sz) return 0; + if (flags & BPF_F_CPU) { + if (map->def.type != BPF_MAP_TYPE_PERCPU_ARRAY) + return -EINVAL; + if (cpu != BPF_ALL_CPUS && cpu >= libbpf_num_possible_cpus()) + return -E2BIG; + if (map->def.value_size != value_sz) { + pr_warn("map '%s': unexpected value size %zu provided, expected %u\n", + map->name, value_sz, map->def.value_size); + return -EINVAL; + } + return 0; + } + switch (map->def.type) { case BPF_MAP_TYPE_PERCPU_ARRAY: case BPF_MAP_TYPE_PERCPU_HASH: @@ -10633,32 +10647,62 @@ int bpf_map__lookup_elem(const struct bpf_map *map, { int err; - err = validate_map_op(map, key_sz, value_sz, true); + err = validate_map_op(map, key_sz, value_sz, true, 0, 0); if (err) return libbpf_err(err); return bpf_map_lookup_elem_flags(map->fd, key, value, flags); } +int bpf_map__lookup_elem_opts(const struct bpf_map *map, const void *key, + size_t key_sz, void *value, size_t value_sz, + const struct bpf_map_lookup_elem_opts *opts) +{ + __u64 flags = OPTS_GET(opts, flags, 0); + __u32 cpu = OPTS_GET(opts, cpu, 0); + int err; + + err = validate_map_op(map, key_sz, value_sz, true, flags, cpu); + if (err) + return libbpf_err(err); + + return bpf_map_lookup_elem_opts(map->fd, key, value, opts); +} + int bpf_map__update_elem(const struct bpf_map *map, const void *key, size_t key_sz, const void *value, size_t value_sz, __u64 flags) { int err; - err = validate_map_op(map, key_sz, value_sz, true); + err = validate_map_op(map, key_sz, value_sz, true, 0, 0); if (err) return libbpf_err(err); return bpf_map_update_elem(map->fd, key, value, flags); } +int bpf_map__update_elem_opts(const struct bpf_map *map, const void *key, + size_t key_sz, const void *value, size_t value_sz, + const struct bpf_map_update_elem_opts *opts) +{ + __u64 flags = OPTS_GET(opts, flags, 0); + __u32 cpu = OPTS_GET(opts, cpu, 0); + int err; + + err = validate_map_op(map, key_sz, value_sz, true, flags, cpu); + if (err) + return libbpf_err(err); + + return bpf_map_update_elem_opts(map->fd, key, value, opts); +} + int bpf_map__delete_elem(const struct bpf_map *map, const void *key, size_t key_sz, __u64 flags) { int err; - err = validate_map_op(map, key_sz, 0, false /* check_value_sz */); + err = validate_map_op(map, key_sz, 0, false /* check_value_sz */, 0, 0); if (err) return libbpf_err(err); @@ -10671,7 +10715,7 @@ int bpf_map__lookup_and_delete_elem(const struct bpf_map *map, { int err; - err = validate_map_op(map, key_sz, value_sz, true); + err = validate_map_op(map, key_sz, value_sz, true, 0, 0); if (err) return libbpf_err(err); @@ -10683,7 +10727,7 @@ int bpf_map__get_next_key(const struct bpf_map *map, { int err; - err = validate_map_op(map, key_sz, 0, false /* check_value_sz */); + err = validate_map_op(map, key_sz, 0, false /* check_value_sz */, 0, 0); if (err) return libbpf_err(err); diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h index d1cf813a057b..fd4940759bc9 100644 --- a/tools/lib/bpf/libbpf.h +++ b/tools/lib/bpf/libbpf.h @@ -1168,13 +1168,7 @@ LIBBPF_API struct bpf_map *bpf_map__inner_map(struct bpf_map *map); * @param key pointer to memory containing bytes of the key used for lookup * @param key_sz size in bytes of key data, needs to match BPF map definition's **key_size** * @param value pointer to memory in which looked up value will be stored - * @param value_sz size in byte of value data memory; it has to match BPF map - * definition's **value_size**. For per-CPU BPF maps value size has to be - * a product of BPF map value size and number of possible CPUs in the system - * (could be fetched with **libbpf_num_possible_cpus()**). Note also that for - * per-CPU values value size has to be aligned up to closest 8 bytes for - * alignment reasons, so expected size is: `round_up(value_size, 8) - * * libbpf_num_possible_cpus()`. + * @param value_sz refer to **bpf_map__lookup_elem_opts()**'s description. * @flags extra flags passed to kernel for this operation * @return 0, on success; negative error, otherwise * @@ -1185,6 +1179,32 @@ LIBBPF_API int bpf_map__lookup_elem(const struct bpf_map *map, const void *key, size_t key_sz, void *value, size_t value_sz, __u64 flags); +/** + * @brief **bpf_map__lookup_elem_opts()** allows to lookup BPF map value + * corresponding to provided key with options. + * @param map BPF map to lookup element in + * @param key pointer to memory containing bytes of the key used for lookup + * @param key_sz size in bytes of key data, needs to match BPF map definition's **key_size** + * @param value pointer to memory in which looked up value will be stored + * @param value_sz size in byte of value data memory; it has to match BPF map + * definition's **value_size**. For per-CPU BPF maps value size can be + * definition's **value_size** if **BPF_F_CPU** is specified in **opts->flags**, + * otherwise a product of BPF map value size and number of possible CPUs in the + * system (could be fetched with **libbpf_num_possible_cpus()**). Note else that + * for per-CPU values value size has to be aligned up to closest 8 bytes for + * alignment reasons, so expected size is: `round_up(value_size, 8) + * * libbpf_num_possible_cpus()`. + * @opts extra options passed to kernel for this operation + * @return 0, on success; negative error, otherwise + * + * **bpf_map__lookup_elem_opts()** is high-level equivalent of + * **bpf_map_lookup_elem_opts()** API with added check for key and value size. + */ +LIBBPF_API int bpf_map__lookup_elem_opts(const struct bpf_map *map, + const void *key, size_t key_sz, + void *value, size_t value_sz, + const struct bpf_map_lookup_elem_opts *opts); + /** * @brief **bpf_map__update_elem()** allows to insert or update value in BPF * map that corresponds to provided key. @@ -1209,6 +1229,25 @@ LIBBPF_API int bpf_map__update_elem(const struct bpf_map *map, const void *key, size_t key_sz, const void *value, size_t value_sz, __u64 flags); +/** + * @brief **bpf_map__update_elem_opts()** allows to insert or update value in BPF + * map that corresponds to provided key with options. + * @param map BPF map to insert to or update element in + * @param key pointer to memory containing bytes of the key + * @param key_sz size in bytes of key data, needs to match BPF map definition's **key_size** + * @param value pointer to memory containing bytes of the value + * @param value_sz refer to **bpf_map__lookup_elem_opts()**'s description. + * @opts extra options passed to kernel for this operation + * @return 0, on success; negative error, otherwise + * + * **bpf_map__update_elem_opts()** is high-level equivalent of + * **bpf_map_update_elem_opts()** API with added check for key and value size. + */ +LIBBPF_API int bpf_map__update_elem_opts(const struct bpf_map *map, + const void *key, size_t key_sz, + const void *value, size_t value_sz, + const struct bpf_map_update_elem_opts *opts); + /** * @brief **bpf_map__delete_elem()** allows to delete element in BPF map that * corresponds to provided key. diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index d7bd463e7017..fa415d9f26ce 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -448,4 +448,9 @@ LIBBPF_1.6.0 { } LIBBPF_1.5.0; LIBBPF_1.7.0 { + global: + bpf_map__lookup_elem_opts; + bpf_map__update_elem_opts; + bpf_map_lookup_elem_opts; + bpf_map_update_elem_opts; } LIBBPF_1.6.0; diff --git a/tools/lib/bpf/libbpf_common.h b/tools/lib/bpf/libbpf_common.h index 8fe248e14eb6..84ca89ace1be 100644 --- a/tools/lib/bpf/libbpf_common.h +++ b/tools/lib/bpf/libbpf_common.h @@ -89,4 +89,18 @@ memcpy(&NAME, &___##NAME, sizeof(NAME)); \ } while (0) +struct bpf_map_update_elem_opts { + size_t sz; /* size of this struct for forward/backward compatibility */ + __u64 flags; + __u32 cpu; + size_t:0; +}; + +struct bpf_map_lookup_elem_opts { + size_t sz; /* size of this struct for forward/backward compatibility */ + __u64 flags; + __u32 cpu; + size_t:0; +}; + #endif /* __LIBBPF_LIBBPF_COMMON_H */ -- 2.50.1