From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 A6E9A1AA1E8; Thu, 24 Apr 2025 15:39:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745509157; cv=none; b=hkKXMSaI8HeW6e+ez2patunV6TOqpxnWQcStGVcoyt92DPnYR+V/AIcDlXRCk3vPT2He3iBXJuCpyiFCPoPbXwIX5RM1GcbC7JpCf5hJl7V1ms7UPtqWvHI6X/zfRR0s7XvSqisDI5wW6iMctwicOxllEXFChjuZTEMu2YFvPeI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745509157; c=relaxed/simple; bh=bG/8KkN6g08cy15bXp7SU/ACSW5hKRw9IHiEHmSO58w=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=YAlyjtTExOyvF/ocRuTvCEP57hI82s9B6Rojb6wglVUwOqPmw6g7BP7MINrytjBIi16MfKJ9FhrebUVj+Vy/6IkCc1yObl3iqfW5ftKbELCU6d7AOTPvHR8rTgMci2VJN0JK8szMxOtanfGf3elBvB+vsoHSmhuRF0OlbyCb2g8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=heD40srs; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="heD40srs" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 03722C4CEEC; Thu, 24 Apr 2025 15:39:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1745509157; bh=bG/8KkN6g08cy15bXp7SU/ACSW5hKRw9IHiEHmSO58w=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=heD40srsNULa7S6ZUDtl7iM2UnAy9jC0BmBCAdtwpwi1GuLS0RMUOCjOGviqqkxvG Dz81/PJ0XPdH9IFjNF9Oobg2UlMPSfcvJcz7gGJadUx4unyVFeJC2aZvEbTifyPrvI Dc8tEjq+SlRvuekHUYJT4+JGEa+92Fz52mjnF3uvsDpyYhLupZqPuRkkNcKasCmZzi dr7Ye1TB49rULcVUdYKjypzUn1gkyikwGZw+n8y+tuz1dDBsgifvwLRvlKIiz4r74u QeJ1MaCtSjggBz73l7X82W0zdMjPRNPX5D7mBECj5bfeARxOQCiEpnVgF6chy97eHS GUJD11dpRlaMw== Message-ID: <783dacd8-6782-484a-8934-f4a5d20eeddb@kernel.org> Date: Thu, 24 Apr 2025 17:39:10 +0200 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH bpf-next v2] bpf: Allow XDP dev-bound programs to perform XDP_REDIRECT into maps To: Lorenzo Bianconi , Alexei Starovoitov , Daniel Borkmann , John Fastabend , Andrii Nakryiko , Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , "David S. Miller" , Jakub Kicinski , Mykola Lysenko , Shuah Khan Cc: bpf@vger.kernel.org, netdev@vger.kernel.org, linux-kselftest@vger.kernel.org References: <20250423-xdp-prog-bound-fix-v2-1-51742a5dfbce@kernel.org> Content-Language: en-US From: Jesper Dangaard Brouer In-Reply-To: <20250423-xdp-prog-bound-fix-v2-1-51742a5dfbce@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 23/04/2025 19.44, Lorenzo Bianconi wrote: > In the current implementation if the program is dev-bound to a specific > device, it will not be possible to perform XDP_REDIRECT into a DEVMAP > or CPUMAP even if the program is running in the driver NAPI context and > it is not attached to any map entry. This seems in contrast with the > explanation available in bpf_prog_map_compatible routine. > Fix the issue introducing __bpf_prog_map_compatible utility routine in > order to avoid bpf_prog_is_dev_bound() check running bpf_check_tail_call() > at program load time (bpf_prog_select_runtime()). > Continue forbidding to attach a dev-bound program to XDP maps > (BPF_MAP_TYPE_PROG_ARRAY, BPF_MAP_TYPE_DEVMAP and BPF_MAP_TYPE_CPUMAP). > > Fixes: 3d76a4d3d4e59 ("bpf: XDP metadata RX kfuncs") > Signed-off-by: Lorenzo Bianconi > --- > Changes in v2: > - Introduce __bpf_prog_map_compatible() utility routine in order to skip > bpf_prog_is_dev_bound check in bpf_check_tail_call() > - Extend xdp_metadata selftest > - Link to v1:https://lore.kernel.org/r/20250422-xdp-prog-bound-fix-v1-1-0b581fa186fe@kernel.org > --- > kernel/bpf/core.c | 27 +++++++++++++--------- > .../selftests/bpf/prog_tests/xdp_metadata.c | 22 +++++++++++++++++- > tools/testing/selftests/bpf/progs/xdp_metadata.c | 13 +++++++++++ > 3 files changed, 50 insertions(+), 12 deletions(-) > > diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c > index ba6b6118cf504041278d05417c4212d57be6fca0..a3e571688421196c3ceaed62b3b59b62a0258a8c 100644 > --- a/kernel/bpf/core.c > +++ b/kernel/bpf/core.c > @@ -2358,8 +2358,8 @@ static unsigned int __bpf_prog_ret0_warn(const void *ctx, > return 0; > } > > -bool bpf_prog_map_compatible(struct bpf_map *map, > - const struct bpf_prog *fp) > +static bool __bpf_prog_map_compatible(struct bpf_map *map, > + const struct bpf_prog *fp) > { > enum bpf_prog_type prog_type = resolve_prog_type(fp); > bool ret; > @@ -2368,14 +2368,6 @@ bool bpf_prog_map_compatible(struct bpf_map *map, > if (fp->kprobe_override) > return false; > > - /* XDP programs inserted into maps are not guaranteed to run on > - * a particular netdev (and can run outside driver context entirely > - * in the case of devmap and cpumap). Until device checks > - * are implemented, prohibit adding dev-bound programs to program maps. > - */ > - if (bpf_prog_is_dev_bound(aux)) > - return false; > - > spin_lock(&map->owner.lock); > if (!map->owner.type) { > /* There's no owner yet where we could check for > @@ -2409,6 +2401,19 @@ bool bpf_prog_map_compatible(struct bpf_map *map, > return ret; > } > > +bool bpf_prog_map_compatible(struct bpf_map *map, const struct bpf_prog *fp) > +{ > + /* XDP programs inserted into maps are not guaranteed to run on > + * a particular netdev (and can run outside driver context entirely > + * in the case of devmap and cpumap). Until device checks > + * are implemented, prohibit adding dev-bound programs to program maps. > + */ > + if (bpf_prog_is_dev_bound(fp->aux)) > + return false; > + > + return __bpf_prog_map_compatible(map, fp); > +} > + > static int bpf_check_tail_call(const struct bpf_prog *fp) > { > struct bpf_prog_aux *aux = fp->aux; > @@ -2421,7 +2426,7 @@ static int bpf_check_tail_call(const struct bpf_prog *fp) > if (!map_type_contains_progs(map)) > continue; > > - if (!bpf_prog_map_compatible(map, fp)) { > + if (!__bpf_prog_map_compatible(map, fp)) { > ret = -EINVAL; > goto out; > } Does this change allow us to have a dev_bound BPF-prog that have tail-call BPF-progs that are not dev_bound? The use-case is a dev_bound BPF-prog that reads e.g. HW vlan, store this in data_meta (or a per CPU array), and then tail-calls another BPF-prog that reads the data stored (from data_meta area). Maybe this is already supported before? --Jesper