From patchwork Wed Feb 21 16:25:16 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Benjamin Tissoires X-Patchwork-Id: 774725 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 7FCAB81727; Wed, 21 Feb 2024 16:25:24 +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=1708532724; cv=none; b=K/jUXswQUCWXaQjKeJBwViS+IUb5iFI/Gs6Y8QCJVDuWa8SB3yXtI8pJHDtf7deRLeD0B8JKfD+vs4m+W6bg8iT6XFI4YuadsSQkOfm0adbldIm75TrJ/4cs+PeERqzGsntqdjUn6PzM9iwBni7kp4PUzPV6feFuuF8rzIRnS/U= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708532724; c=relaxed/simple; bh=zRZq7ktIelCZZWJLLT8Fm+ahdGyQ/siOzgpKQQJWNz8=; h=From:Subject:Date:Message-Id:MIME-Version:Content-Type:To:Cc; b=d3YN/IojyFSgXJZ5RnxXUjIPTw86u5bf619adr7O5JQpF0FeF3YyeUhsfmBYJwE2H1MpYkefTYrgf90GuUvG9LYsHQn9Ji0jYp68//FzPZbjH0wXdamz2kJacN12ezFOKKiNKfP8u6fltL7daMaBsNri056lVVJ8APaf3tne/nw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=J7VmYAdG; 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="J7VmYAdG" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F1EFDC433C7; Wed, 21 Feb 2024 16:25:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1708532724; bh=zRZq7ktIelCZZWJLLT8Fm+ahdGyQ/siOzgpKQQJWNz8=; h=From:Subject:Date:To:Cc:From; b=J7VmYAdGn2jUz4zfl8Q1nrvAFDCMu33mXMDJumE3auykorUG6ptw9I3uoM8F2Xxu9 ywwCB8q72c/PkSEpeHZB7+M1tG2lhQzH7wkvHR01yKaQk6SITWhmBp2rmTHQQs8Yi4 rUDZAJpRSORoiIz7PXIHmAEBGp+tKw1P4d0xIATwQI+21JZ/wIz+Yh538GFbA3rC2w UPpuz0NdZGYrcenQ47c5qLvx6EGVdre+ob3iXI1Vd4e5slKW4gbSwkqd4OeCR7yldu xGF7jb20SvqRkTLVZlGKp0kmZTj9/q8izfV0I2wgzeXGwLAKQk4YaLlZDWBCcOLYe4 aBB+MPE1O5U9g== From: Benjamin Tissoires Subject: [PATCH RFC bpf-next v3 00/16] sleepable bpf_timer (was: allow HID-BPF to do device IOs) Date: Wed, 21 Feb 2024 17:25:16 +0100 Message-Id: <20240221-hid-bpf-sleepable-v3-0-1fb378ca6301@kernel.org> Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-B4-Tracking: v=1; b=H4sIAOwj1mUC/23NQQrCMBAF0KvIrI0kMWmtK0HwAG7FRZNM22BJS 1JCpfTupsWFQpf/M//NBAG9xQDn3QQeow22cykc9zvQTelqJNakDJxyQTmVpLGGqL4ioUXsS9U i0ZTxjFamYFpA2vUeKzuu5gPut+vSLQuH4wDPFBobhs6/15+RrWdfvtjgIyOUCK1PhVSyNMpcX ugdtofO1ysX+Q/BxBbBEyFzmSkqRc7FPzHP8wc3GdM5BwEAAA== To: 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 , Jiri Kosina , Benjamin Tissoires , Jonathan Corbet , Shuah Khan Cc: bpf@vger.kernel.org, linux-kernel@vger.kernel.org, linux-input@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, Benjamin Tissoires X-Mailer: b4 0.12.4 X-Developer-Signature: v=1; a=ed25519-sha256; t=1708532719; l=5588; i=bentiss@kernel.org; s=20230215; h=from:subject:message-id; bh=zRZq7ktIelCZZWJLLT8Fm+ahdGyQ/siOzgpKQQJWNz8=; b=Syk9/ZSBxBEt26q6j5DdxWU1oXWH+kMI3/GAMo63FMLAWFUnwvT3WuDR4vVGJe2WRI69d3JDF mwgq7Sp08fFAN9VvpswTg23wXbBgheQFqyl+trA1lwwGax8ra3jMQI1 X-Developer-Key: i=bentiss@kernel.org; a=ed25519; pk=7D1DyAVh6ajCkuUTudt/chMuXWIJHlv2qCsRkIizvFw= [Partly a RFC/formal submission: there are still FIXMEs in the code] [Also using bpf-next as the base tree for HID changes as there will be conflicting changes otherwise, so I'm personaly fine for the HID commits to go through bpf-next] IMO, patches 1-3 and 9-14 are ready to go, rest is still pending review. For reference, the use cases I have in mind: --- Basically, I need to be able to defer a HID-BPF program for the following reasons (from the aforementioned patch): 1. defer an event: Sometimes we receive an out of proximity event, but the device can not be trusted enough, and we need to ensure that we won't receive another one in the following n milliseconds. So we need to wait those n milliseconds, and eventually re-inject that event in the stack. 2. inject new events in reaction to one given event: We might want to transform one given event into several. This is the case for macro keys where a single key press is supposed to send a sequence of key presses. But this could also be used to patch a faulty behavior, if a device forgets to send a release event. 3. communicate with the device in reaction to one event: We might want to communicate back to the device after a given event. For example a device might send us an event saying that it came back from sleeping state and needs to be re-initialized. Currently we can achieve that by keeping a userspace program around, raise a bpf event, and let that userspace program inject the events and commands. However, we are just keeping that program alive as a daemon for just scheduling commands. There is no logic in it, so it doesn't really justify an actual userspace wakeup. So a kernel workqueue seems simpler to handle. The other part I'm not sure is whether we can say that BPF maps of type queue/stack can be used in sleepable context. I don't see any warning when running the test programs, but that's probably not a guarantee I'm doing the things properly :) Cheers, Benjamin To: Alexei Starovoitov To: Daniel Borkmann To: John Fastabend To: Andrii Nakryiko To: Martin KaFai Lau To: Eduard Zingerman To: Song Liu To: Yonghong Song To: KP Singh To: Stanislav Fomichev To: Hao Luo To: Jiri Olsa To: Jiri Kosina To: Benjamin Tissoires To: Jonathan Corbet To: Shuah Khan Cc: Cc: Cc: Cc: Cc: Signed-off-by: Benjamin Tissoires --- Changes in v3: - fixed the crash from v2 - changed the API to have only BPF_F_TIMER_SLEEPABLE for bpf_timer_start() - split the new kfuncs/verifier patch into several sub-patches, for easier reviews - Link to v2: https://lore.kernel.org/r/20240214-hid-bpf-sleepable-v2-0-5756b054724d@kernel.org Changes in v2: - make use of bpf_timer (and dropped the custom HID handling) - implemented bpf_timer_set_sleepable_cb as a kfunc - still not implemented global subprogs - no sleepable bpf_timer selftests yet - Link to v1: https://lore.kernel.org/r/20240209-hid-bpf-sleepable-v1-0-4cc895b5adbd@kernel.org --- Benjamin Tissoires (16): bpf/verifier: allow more maps in sleepable bpf programs bpf/verifier: introduce in_sleepable() helper bpf/verifier: add is_async_callback_calling_insn() helper bpf/helpers: introduce sleepable bpf_timers bpf/verifier: add bpf_timer as a kfunc capable type bpf/helpers: introduce bpf_timer_set_sleepable_cb() kfunc bpf/helpers: mark the callback of bpf_timer_set_sleepable_cb() as sleepable bpf/verifier: do_misc_fixups for is_bpf_timer_set_sleepable_cb_kfunc HID: bpf/dispatch: regroup kfuncs definitions HID: bpf: export hid_hw_output_report as a BPF kfunc selftests/hid: Add test for hid_bpf_hw_output_report HID: bpf: allow to inject HID event from BPF selftests/hid: add tests for hid_bpf_input_report HID: bpf: allow to use bpf_timer_set_sleepable_cb() in tracing callbacks. selftests/hid: add test for bpf_timer selftests/hid: add KASAN to the VM tests Documentation/hid/hid-bpf.rst | 2 +- drivers/hid/bpf/hid_bpf_dispatch.c | 232 ++++++++++++++------- drivers/hid/hid-core.c | 2 + include/linux/bpf_verifier.h | 2 + include/linux/hid_bpf.h | 3 + include/uapi/linux/bpf.h | 4 + kernel/bpf/helpers.c | 140 +++++++++++-- kernel/bpf/verifier.c | 114 ++++++++-- tools/testing/selftests/hid/config.common | 1 + tools/testing/selftests/hid/hid_bpf.c | 195 ++++++++++++++++- tools/testing/selftests/hid/progs/hid.c | 198 ++++++++++++++++++ .../testing/selftests/hid/progs/hid_bpf_helpers.h | 8 + 12 files changed, 795 insertions(+), 106 deletions(-) --- base-commit: 5c331823b3fc52ffd27524bf5b7e0d137114f470 change-id: 20240205-hid-bpf-sleepable-c01260fd91c4 Best regards,