From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 586EDC4332F for ; Tue, 29 Mar 2022 13:04:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237105AbiC2NGZ (ORCPT ); Tue, 29 Mar 2022 09:06:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41720 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233283AbiC2NGV (ORCPT ); Tue, 29 Mar 2022 09:06:21 -0400 Received: from mga18.intel.com (mga18.intel.com [134.134.136.126]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BAB82340EA; Tue, 29 Mar 2022 06:04:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1648559077; x=1680095077; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=9kQjeBJCbRw818KO3/vAUpiMndjw9ObV4lqk2smtPXg=; b=TvVjiGzN0dqRsyjfS0v1rOg8ENVdcfuWk/raaHhIIqijKs2V0Okhtxnb JOt0CakHY+9LaKiPSIOEUdiNWxnkM+v/4cjieVjmIfZuGtsHdQuy1HeMY A71d2om/sXIXy2f69csiz8Tx2YhAKKt+nOLqXz/6eok7KtTVYMpHZVyM4 O7Qs4BqVZ0WDD5lY57TmYyZ5n1PDsXSs3/Od7w2VV7iZncbGbFq2OYeaC 68jajI9v6c/y3m5QiUdd8XQemcLm8rQFftEvJmJcxqpW+oMvP8EBnZUQg firWHDEA6r2w6Jz23sr3tao5E9B8zP1n0Ejx+DB3KXj5IxMzw9DA1hPHq A==; X-IronPort-AV: E=McAfee;i="6200,9189,10300"; a="241399042" X-IronPort-AV: E=Sophos;i="5.90,220,1643702400"; d="scan'208";a="241399042" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Mar 2022 06:04:36 -0700 X-IronPort-AV: E=Sophos;i="5.90,220,1643702400"; d="scan'208";a="694708112" Received: from gboschi-mobl.ger.corp.intel.com (HELO [10.249.42.217]) ([10.249.42.217]) by fmsmga001-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Mar 2022 06:04:30 -0700 Message-ID: <0a30942b-e6c9-72fb-d012-4b8a6a16ae42@linux.intel.com> Date: Tue, 29 Mar 2022 16:04:28 +0300 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.5.0 Subject: Re: [PATCH bpf-next v3 00/17] Introduce eBPF support for HID devices Content-Language: en-US To: Benjamin Tissoires , Greg KH , Jiri Kosina , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Shuah Khan , Dave Marchevsky , Joe Stringer , Jonathan Corbet Cc: linux-kernel@vger.kernel.org, linux-input@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-doc@vger.kernel.org References: <20220318161528.1531164-1-benjamin.tissoires@redhat.com> From: Tero Kristo In-Reply-To: <20220318161528.1531164-1-benjamin.tissoires@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Benjamin, I tested this iteration of the set, and I faced couple of problems with it. 1) There were some conflicts as I could not figure out the correct kernel commit on which to apply the series on. I applied this on top of last weeks bpf-next (see below) with some local merge fixes. commit 2af7e566a8616c278e1d7287ce86cd3900bed943 (bpf-next/master, bpf-next/for-next) Author: Saeed Mahameed Date:   Tue Mar 22 10:22:24 2022 -0700     net/mlx5e: Fix build warning, detected write beyond size of field 2) hid_is_valid_access() causes some trouble and it rejects pretty much every BPF program which tries to use ctx->retval. This appears to be because prog->expected_attach_type is not populated, I had to apply below local tweak to overcome this problem: diff --git a/kernel/bpf/hid.c b/kernel/bpf/hid.c index 30a62e8e0f0a..bf64411e6e9b 100644 --- a/kernel/bpf/hid.c +++ b/kernel/bpf/hid.c @@ -180,8 +180,7 @@ static bool hid_is_valid_access(int off, int size,         case offsetof(struct hid_bpf_ctx, retval):                 if (size != size_default)                         return false; -               return (prog->expected_attach_type == BPF_HID_USER_EVENT || -                       prog->expected_attach_type == BPF_HID_DRIVER_EVENT); +               return true;         default:                 if (size != size_default)                         return false; Proper fix would probably be to actually populate the expected_attach_type, but I could not figure out quickly where this should be done, or whether it is actually done on some other base commit. With those, for the whole series: Tested-by: Tero Kristo On 18/03/2022 18:15, Benjamin Tissoires wrote: > Hi, > > This is a followup of my v1 at [0] and v2 at [1]. > > The short summary of the previous cover letter and discussions is that > HID could benefit from BPF for the following use cases: > > - simple fixup of report descriptor: > benefits are faster development time and testing, with the produced > bpf program being shipped in the kernel directly (the shipping part > is *not* addressed here). > > - Universal Stylus Interface: > allows a user-space program to define its own kernel interface > > - Surface Dial: > somehow similar to the previous one except that userspace can decide > to change the shape of the exported device > > - firewall: > still partly missing there, there is not yet interception of hidraw > calls, but it's coming in a followup series, I promise > > - tracing: > well, tracing. > > > I think I addressed the comments from the previous version, but there are > a few things I'd like to note here: > > - I did not take the various rev-by and tested-by (thanks a lot for those) > because the uapi changed significantly in v3, so I am not very confident > in taking those rev-by blindly > > - I mentioned in my discussion with Song that I'll put a summary of the uapi > in the cover letter, but I ended up adding a (long) file in the Documentation > directory. So please maybe start by reading 17/17 to have an overview of > what I want to achieve > > - I added in the libbpf and bpf the new type BPF_HID_DRIVER_EVENT, even though > I don't have a user of it right now in the kernel. I wanted to have them in > the docs, but we might not want to have them ready here. > In terms of code, it just means that we can attach such programs types > but that they will never get triggered. > > Anyway, I have been mulling on this for the past 2 weeks, and I think that > maybe sharing this now is better than me just starring at the code over and > over. > > > Short summary of changes: > > v3: > === > > - squashed back together most of the libbpf and bpf changes into bigger > commits that give a better overview of the whole interactions > > - reworked the user API to not expose .data as a directly accessible field > from the context, but instead forces everyone to use hid_bpf_get_data (or > get/set_bits) > > - added BPF_HID_DRIVER_EVENT (see note above) > > - addressed the various nitpicks from v2 > > - added a big Documentation file (and so adding now the doc maintainers to the > long list of recipients) > > v2: > === > > - split the series by subsystem (bpf, HID, libbpf, selftests and > samples) > > - Added an extra patch at the beginning to not require CAP_NET_ADMIN for > BPF_PROG_TYPE_LIRC_MODE2 (please shout if this is wrong) > > - made the bpf context attached to HID program of dynamic size: > * the first 1 kB will be able to be addressed directly > * the rest can be retrieved through bpf_hid_{set|get}_data > (note that I am definitivey not happy with that API, because there > is part of it in bits and other in bytes. ouch) > > - added an extra patch to prevent non GPL HID bpf programs to be loaded > of type BPF_PROG_TYPE_HID > * same here, not really happy but I don't know where to put that check > in verifier.c > > - added a new flag BPF_F_INSERT_HEAD for BPF_LINK_CREATE syscall when in > used with HID program types. > * this flag is used for tracing, to be able to load a program before > any others that might already have been inserted and that might > change the data stream. > > Cheers, > Benjamin > > > > [0] https://lore.kernel.org/linux-input/20220224110828.2168231-1-benjamin.tissoires@redhat.com/T/#t > [1] https://lore.kernel.org/linux-input/20220304172852.274126-1-benjamin.tissoires@redhat.com/T/#t > > > Benjamin Tissoires (17): > bpf: add new is_sys_admin_prog_type() helper > bpf: introduce hid program type > bpf/verifier: prevent non GPL programs to be loaded against HID > libbpf: add HID program type and API > HID: hook up with bpf > HID: allow to change the report descriptor from an eBPF program > selftests/bpf: add tests for the HID-bpf initial implementation > selftests/bpf: add report descriptor fixup tests > selftests/bpf: Add a test for BPF_F_INSERT_HEAD > selftests/bpf: add test for user call of HID bpf programs > samples/bpf: add new hid_mouse example > bpf/hid: add more HID helpers > HID: bpf: implement hid_bpf_get|set_bits > HID: add implementation of bpf_hid_raw_request > selftests/bpf: add tests for hid_{get|set}_bits helpers > selftests/bpf: add tests for bpf_hid_hw_request > Documentation: add HID-BPF docs > > Documentation/hid/hid-bpf.rst | 444 +++++++++++ > Documentation/hid/index.rst | 1 + > drivers/hid/Makefile | 1 + > drivers/hid/hid-bpf.c | 328 ++++++++ > drivers/hid/hid-core.c | 34 +- > include/linux/bpf-hid.h | 127 +++ > include/linux/bpf_types.h | 4 + > include/linux/hid.h | 36 +- > include/uapi/linux/bpf.h | 67 ++ > include/uapi/linux/bpf_hid.h | 71 ++ > include/uapi/linux/hid.h | 10 + > kernel/bpf/Makefile | 3 + > kernel/bpf/btf.c | 1 + > kernel/bpf/hid.c | 728 +++++++++++++++++ > kernel/bpf/syscall.c | 27 +- > kernel/bpf/verifier.c | 7 + > samples/bpf/.gitignore | 1 + > samples/bpf/Makefile | 4 + > samples/bpf/hid_mouse_kern.c | 117 +++ > samples/bpf/hid_mouse_user.c | 129 +++ > tools/include/uapi/linux/bpf.h | 67 ++ > tools/lib/bpf/libbpf.c | 23 +- > tools/lib/bpf/libbpf.h | 2 + > tools/lib/bpf/libbpf.map | 1 + > tools/testing/selftests/bpf/config | 3 + > tools/testing/selftests/bpf/prog_tests/hid.c | 788 +++++++++++++++++++ > tools/testing/selftests/bpf/progs/hid.c | 205 +++++ > 27 files changed, 3204 insertions(+), 25 deletions(-) > create mode 100644 Documentation/hid/hid-bpf.rst > create mode 100644 drivers/hid/hid-bpf.c > create mode 100644 include/linux/bpf-hid.h > create mode 100644 include/uapi/linux/bpf_hid.h > create mode 100644 kernel/bpf/hid.c > create mode 100644 samples/bpf/hid_mouse_kern.c > create mode 100644 samples/bpf/hid_mouse_user.c > create mode 100644 tools/testing/selftests/bpf/prog_tests/hid.c > create mode 100644 tools/testing/selftests/bpf/progs/hid.c >