From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f181.google.com (mail-pl1-f181.google.com [209.85.214.181]) (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 BEE7127F741; Thu, 24 Apr 2025 16:07:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.181 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745510830; cv=none; b=FIR5SGQyXyVKTXqksS+MhtPgdzjKNqF/cGoffnpYJvgKjUNpKBqPDy8nOpkwogt/xE9W7g87bKLKmqmgAduaZpOBNCCr1ZGC+016vRL0oTMniAJKXzqCwbcWUhFlTL2L2TAzoAgtTxCcsiOGnbFDhTG/Y6T8y1afpWnfhuxUUOQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745510830; c=relaxed/simple; bh=Dvocved7LoWD4r5DAQ7IXH0mS+GeN7+ssaae+GrmBP4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=h2DgysERbMiXafXkavey953GqdZ6FIyWuuAOHbb55PTbRCWoM41aphQBxX11RORciOfx4C/uXbjhVOLwQBhxB6iU0HaSBm4hBW56/Ndc6LrvJfBUUHRUJgED0Q8BVZqWFjcXSUx1QIzpLMfhACFE+fVJpAwW1QMc7lM4LY6694o= 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=KmIzhue3; arc=none smtp.client-ip=209.85.214.181 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="KmIzhue3" Received: by mail-pl1-f181.google.com with SMTP id d9443c01a7336-224341bbc1dso15917475ad.3; Thu, 24 Apr 2025 09:07:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1745510828; x=1746115628; darn=vger.kernel.org; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date:from:to :cc:subject:date:message-id:reply-to; bh=b6Hg2Hn61cEifSZ7Yz6FWUl6aS6FdXU7iBAnedM8l0w=; b=KmIzhue3VhoSAkp3Ha4P7G7OMDnBdLxdBzN3ki/VD/I5fJ4zfMxNdaFZfnWhm7UyCa EbMGH8QgMmovq2bVrIuQjDPHyz+QD+qgeHfmK6OFu6VIrGdNbvuB4YDOTVUO0gWyMzs9 8zaSIhmBjwhCjeSUdqaPRKLmA4ECqztd8oAN3U04Gdj+bBaXiZzvvTCS7x6jkhkVdrE5 yeLa3qSVf9RDAvWJhj/PftkdbbAUiwMIEWrn6H+3AdlesygjczVGKJaOYhSCmUG/6bYJ qH8/L55FI0MFLrFA7QMo7BrBaogbG6M6jh9veTGtctfBsuM2viQZjUKfNo81KoAbV8Fv Ht3A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1745510828; x=1746115628; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=b6Hg2Hn61cEifSZ7Yz6FWUl6aS6FdXU7iBAnedM8l0w=; b=urdcHFo9i+iJXmv5X4/hc7av3kKiJAVgxnVYaOu5IRAGxdRVcJkL17ik5y247Orxte sOKMgd0L3WmI6RjktD+f+aFs6tN8xsPnWd25DHEQqZh9NUal6Vq4z7sQic96xmPc4Sot X6QGGqNK19BAas57veXUya0FKadFGfsQTv6rXhgvu/lSFYub4Ew2NLoTZGwRzijiX8Sh +B6N/6N6hpoghDLnpQC3rL830PHMYGS+AHF5S9z9OmeinjsOpC1V36llTkuIitTXAcdk 6WM0O9exj5HUGR+h5jqtmn7JJRPZ7VDT3vP1G0E1wTNSj3FNEfHDmqK9q0p+t4lTiH/d JQTw== X-Forwarded-Encrypted: i=1; AJvYcCU6acE59Xtv7FN+aZ+gL+LImLv7RkJT3Qy5J3wuOmHTbEC87DSFRluZ4Bt/D1vnSpd1UQk=@vger.kernel.org, AJvYcCXYENR+5SrVYNDhBGR9hjert7wVDBUce5n7rKzJOKJZpw2YEdHTm49MyNWP8UUzZhDFjX4stQEXcDZWIwFTut7d@vger.kernel.org, AJvYcCXy01f6mImwxzD9Uzgih+0LxXtJ8LPP6mHIG4ezOlC8/y2K0w9IPFsqSDrAYSWwpqMp2BoYJ8vV@vger.kernel.org X-Gm-Message-State: AOJu0YxQFkrZy9vwlMtAFZbAJO54vEiqiLSt6WNX+wKeT6OrpqAK4Lyy K6u8lgASqaZsdwhq+x4nof0mxaz81hA9esS+fpD0pRYA2DaY/Lvg/K/6 X-Gm-Gg: ASbGncuHTn8pNF5MlB8fz+hVdHpsNizehoSSvRHuwYRay0B6ytEHnAkfZAmg3o4mbzL 2YHEUXtavBjzBOSOCAJE4RfaXeocO5xte8XAD6fYbS8nXT/A649y78iJU3f1NBasN8hHA5zfe8n H6HKrSLtbazgraLeiY6vvgmCQ5j9G/hddvnX7xHw94jyPRDovkDo9wuyHR2cyfCluhA1SvuS+xV kDk8X4ops+YPP3bve9VGFPsoqTwQazqZVYEX5S49A4EPxqCFns4qvbpgrgJuDtdLbBF1SSRSpfK Ny9SgAYBTFE73wRgApTW+Kh9STIwkRhKDwLltl4z+zmRYvOXR/Y= X-Google-Smtp-Source: AGHT+IHzlejxmjoKnsnH13VbhFKwz7loLzzPczs4uJtSS2scb3BFipVtzCMBUVeGn0S+lmzKDTPAQA== X-Received: by 2002:a17:903:228f:b0:224:c46:d167 with SMTP id d9443c01a7336-22db3bdf7b9mr46689145ad.16.1745510827944; Thu, 24 Apr 2025 09:07:07 -0700 (PDT) Received: from localhost ([2601:646:9e00:f56e:123b:cea3:439a:b3e3]) by smtp.gmail.com with UTF8SMTPSA id d9443c01a7336-22db4dbe5a2sm15287145ad.86.2025.04.24.09.07.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 24 Apr 2025 09:07:07 -0700 (PDT) Date: Thu, 24 Apr 2025 09:07:06 -0700 From: Stanislav Fomichev To: Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= Cc: 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 , Jesper Dangaard Brouer , Mykola Lysenko , Shuah Khan , bpf@vger.kernel.org, netdev@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: Re: [PATCH bpf-next v2] bpf: Allow XDP dev-bound programs to perform XDP_REDIRECT into maps Message-ID: References: <20250423-xdp-prog-bound-fix-v2-1-51742a5dfbce@kernel.org> <87wmb97uyt.fsf@toke.dk> Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <87wmb97uyt.fsf@toke.dk> On 04/24, Toke Høiland-Jørgensen wrote: > Lorenzo Bianconi writes: > > > 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)) { > > Hmm, so this allows devbound programs in tail call maps, right? But > there's no guarantee that a tail call map will always be used for a > particular device, is there? For instance, it could be shared between > multiple XDP programs, bound to different devices, thus getting the > wrong kfunc. Won't this (devbound progs in tail call maps) be still prohibited by a bpf_prog_map_compatible check in prog_fd_array_get_ptr?