From patchwork Mon Apr 8 08:09:25 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Benjamin Tissoires X-Patchwork-Id: 13620712 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 936AC381AA; Mon, 8 Apr 2024 08:09:51 +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=1712563791; cv=none; b=JCTVTr2S0qhjzcDh4aBGDVkuTTwYxX0Ms1zH7dN4bUA/49xaanAu4sxZAODaO8kfisj18Wj561Ae1YMc8E+U0jkWqLM3hieoW3DTQE1U5OebqgG1FMdsdZlBYi6pW1Mr9jDeiu0TRdiAjFD3JCytRuU6IGaFwKEpAq6q1JE/IrM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712563791; c=relaxed/simple; bh=opoiP/Rbs+qNBZARkVbOAqI4I6o0EeLA/hNQduTWd+M=; h=From:Subject:Date:Message-Id:MIME-Version:Content-Type:To:Cc; b=DuKCrpPWI4Y38rO9xus8BonWVmnVdiCpxnufHpEx2CMYYouBUZrNtSevhEI1mGMpuRgbg5xY2fzKSe3qBiaXHrMdY+R1zl9okWqY9WF4qnP8/cNxWGmmsFSuFlQUX0mjfH+bS19grEJf63iVkJaCWpQ0f5aN1954cBRo52A4mqc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=o4E9K6Pr; 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="o4E9K6Pr" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8B087C433F1; Mon, 8 Apr 2024 08:09:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1712563791; bh=opoiP/Rbs+qNBZARkVbOAqI4I6o0EeLA/hNQduTWd+M=; h=From:Subject:Date:To:Cc:From; b=o4E9K6Pr1sSZu7Q9snc9oekJ5JLvoH/H3Q7O+/mCHpRM7HY422mZg7Av47VJ5SyM4 VpA0eAHHmujovdaFp/j2SaNxm5hU0jpMDnrEmkwayoCihH2RKTFb8fqw3XdWd/OWar x1ad5+rLtBQp6yfZcS4kvOchRjVBgF5UX3wQvifkM485Krhd5547KuxAEnruBr0Uyy KvcIrnj4fBDI4xZDomfNA4DXxK5XmgrVc+Q5V7zTJSJ6x7mLLw/roHqh8yZOX1qJgm p6p4XICtFQArZWJkkXzo/C4WYzy7mQJB9QLMk/3c8PWUszVADlHltg47ZeJJGSL0yz kKTGLKXwGllFw== From: Benjamin Tissoires Subject: [PATCH RFC bpf-next v6 0/6] sleepable bpf_timer (was: allow HID-BPF to do device IOs) Date: Mon, 08 Apr 2024 10:09:25 +0200 Message-Id: <20240408-hid-bpf-sleepable-v6-0-0499ddd91b94@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=H4sIADamE2YC/23QzWrDMAwH8FcpPs/DViwn2Wkw2AP0Onbwh9KYh iQ4xbSUvPucMFhGcvwL6SehJ5soBprY2+nJIqUwhaHPQb+cmGtNfyEefM4MBCgBAnkbPLdjw6e OaDS2I+6EBC0aX0unWJ4bIzXhvppf7Pz5sdSWiZ7uN/adQxum2xAf684k17Zfvj7gk+SCK+eqG i0ab/37lWJP3esQLyuXYENIdURAJrBEbQWqEtSeKDYEyCOiyIRsbFFWzuhCyB2h/ohCHv0pqeU KjVUDqARqtSNwQwAcEbhcUdautFiTMeYfMc/zD6BWpgLQAQAA To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , Mykola Lysenko , Shuah Khan Cc: Benjamin Tissoires , bpf@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, Kumar Kartikeya Dwivedi X-Mailer: b4 0.12.4 X-Developer-Signature: v=1; a=ed25519-sha256; t=1712563787; l=5180; i=bentiss@kernel.org; s=20230215; h=from:subject:message-id; bh=opoiP/Rbs+qNBZARkVbOAqI4I6o0EeLA/hNQduTWd+M=; b=DmSpZ5TNjcfhuBTdcxC3bYuZ6RRZ/C8vn1jSU2NZtn4ezrBoy6p8M9BvEsarXWB7hFDQfhkJR WsqBjmeliW7Ab+hL/I7o/+0rpNEPskjQ/eiNNmDSoulugHqJZUuVdGD X-Developer-Key: i=bentiss@kernel.org; a=ed25519; pk=7D1DyAVh6ajCkuUTudt/chMuXWIJHlv2qCsRkIizvFw= New version of the sleepable bpf_timer code. I'm posting this as this is the result of the previous review, so we can have a baseline to compare to. The plan is now to introduce a new user API struct bpf_wq, as the timer API working on softIRQ seems to be quite far away from a wq. 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. bpf_timers are currently running in a soft IRQ context, this patch series implements a sleppable context for them. Cheers, Benjamin To: Alexei Starovoitov To: Daniel Borkmann To: Andrii Nakryiko To: Martin KaFai Lau To: Eduard Zingerman To: Song Liu To: Yonghong Song To: John Fastabend To: KP Singh To: Stanislav Fomichev To: Hao Luo To: Jiri Olsa To: Mykola Lysenko To: Shuah Khan Cc: Benjamin Tissoires Cc: Cc: Cc: --- Changes in v6: - Use of a workqueue to clean up sleepable timers - integrated Kumar's patch instead of mine - Link to v5: https://lore.kernel.org/r/20240322-hid-bpf-sleepable-v5-0-179c7b59eaaa@kernel.org Changes in v5: - took various reviews into account - rewrote the tests to be separated to not have a uggly include - Link to v4: https://lore.kernel.org/r/20240315-hid-bpf-sleepable-v4-0-5658f2540564@kernel.org Changes in v4: - dropped the HID changes, they can go independently from bpf-core - addressed Alexei's and Eduard's remarks - added selftests - Link to v3: https://lore.kernel.org/r/20240221-hid-bpf-sleepable-v3-0-1fb378ca6301@kernel.org 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 (5): bpf/helpers: introduce sleepable bpf_timers bpf/helpers: introduce bpf_timer_set_sleepable_cb() kfunc bpf/helpers: mark the callback of bpf_timer_set_sleepable_cb() as sleepable tools: sync include/uapi/linux/bpf.h selftests/bpf: add sleepable timer tests Kumar Kartikeya Dwivedi (1): bpf: Add support for KF_ARG_PTR_TO_TIMER include/linux/bpf_verifier.h | 1 + include/uapi/linux/bpf.h | 13 ++ kernel/bpf/helpers.c | 202 ++++++++++++++++--- kernel/bpf/verifier.c | 98 +++++++++- tools/include/uapi/linux/bpf.h | 20 +- tools/testing/selftests/bpf/bpf_experimental.h | 5 + .../selftests/bpf/bpf_testmod/bpf_testmod.c | 5 + .../selftests/bpf/bpf_testmod/bpf_testmod_kfunc.h | 1 + tools/testing/selftests/bpf/prog_tests/timer.c | 34 ++++ .../testing/selftests/bpf/progs/timer_sleepable.c | 213 +++++++++++++++++++++ 10 files changed, 553 insertions(+), 39 deletions(-) --- base-commit: 61df575632d6b39213f47810c441bddbd87c3606 change-id: 20240205-hid-bpf-sleepable-c01260fd91c4 Best regards,