From patchwork Fri Mar 15 14:29:24 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Benjamin Tissoires X-Patchwork-Id: 13593530 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 01B833A1B5; Fri, 15 Mar 2024 14:29:37 +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=1710512978; cv=none; b=PLzeHHptjIKeiKzoYkLCxCRop2a5AruwWRwKIAgPrnYI8Vgr5ocBP0OJEhL5iNykUL3S7KjcHP6Le/q+jnlQdfqOtT+ZhLaRPP3EVK6Ub5sw8YHQ1ok7ptFHHa0AOqJhYtSapwHenjUNHeC7mFhy/wdX8jPdTpoGXvc2OjSSr+E= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710512978; c=relaxed/simple; bh=1ba924wm8H+J/VP0musS5De3pBR+nFdLLCYlvLpXQLI=; h=From:Subject:Date:Message-Id:MIME-Version:Content-Type:To:Cc; b=J9/d1xJtvVa41HWAm5N0eRyTEAo07ah7k+kbwlHtLPpQLkqXvrdnBTLXONZ8JrLlKtiPtScJTXx5Fxm8zdPoaWCRROs/35Q6gXS2tRhV8kYotLhB/o6Y2AE6lMGrkEWdFmDaQP/zAOIvyxUz3Nu1MfgpPp6OQGB1y4PC56U7wXo= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=M+PdkJOP; 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="M+PdkJOP" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EAD84C43394; Fri, 15 Mar 2024 14:29:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1710512977; bh=1ba924wm8H+J/VP0musS5De3pBR+nFdLLCYlvLpXQLI=; h=From:Subject:Date:To:Cc:From; b=M+PdkJOPfSmxj4+10sBOVzWow9lG4Iv598TfMtzagZf45HoQ8j694v7UKhzRD8vuw BXgqmrRsuouIyuoulDx5/KsGx3vfP30xGIhfVXMyKyDETwueUlLzRtsX/dZD9zk1LK 338w1U28n0tm0en7Ero4tnCHOJompXKTDk1ww9pbDQwqvqQGdmnQmh1+FCAH3yLzQh l89v4ZSvTUg2OLXyVqUPV+eP3ypvdPKbnq1nwWiy8fb6ohoGJtZyK3uKN7kG1pv7/W CoVoMlQWK3euuNRl4+nhdiPRVMVLA+La7wsJo5PN7+CbWNutCNI3xQM5DZmUPt3x+9 YJF6d6jMbJKHQ== From: Benjamin Tissoires Subject: [PATCH bpf-next v4 0/6] sleepable bpf_timer (was: allow HID-BPF to do device IOs) Date: Fri, 15 Mar 2024 15:29:24 +0100 Message-Id: <20240315-hid-bpf-sleepable-v4-0-5658f2540564@kernel.org> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-B4-Tracking: v=1; b=H4sIAERb9GUC/23Nyw7CIBAF0F8xrMUAhT5c+R/GBY+hJTa0gaapa frvInFRY5c3d+6ZFUUIDiK6nlYUYHbRDT4Ffj4h3UnfAnYmZcQI44QRgTtnsBotjj3AKFUPWBP KSmJNQzVHaTcGsG7J5h19Tj0sE3qkpnNxGsIrP5tp7r9uc+DOFBPMta4boYQ0ytyeEDz0lyG0m ZvZjqD8iGCJEJUoFRG8YvyfKHYEo0dEkQhqVVHVWpYFoT/Etm1vMnf260MBAAA= 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 X-Mailer: b4 0.12.4 X-Developer-Signature: v=1; a=ed25519-sha256; t=1710512973; l=4636; i=bentiss@kernel.org; s=20230215; h=from:subject:message-id; bh=1ba924wm8H+J/VP0musS5De3pBR+nFdLLCYlvLpXQLI=; b=sav/9qNPwA9ZtLUXSrg5FXA4Oawm7aJRfq4uJaFqM3sVlqdMgezCd0eTAETobBNwbkmfs7Z9B e2w7pupjnijCHXLDnAO2X9HN+MJ2kvH8cKfhz4rv7f99Nhq8uMbaRQZ X-Developer-Key: i=bentiss@kernel.org; a=ed25519; pk=7D1DyAVh6ajCkuUTudt/chMuXWIJHlv2qCsRkIizvFw= X-Patchwork-Delegate: bpf@iogearbox.net New version of the sleepable bpf_timer code, without the HID changes, as they can now go through the HID tree independantly. 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 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 (6): 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 tools: sync include/uapi/linux/bpf.h selftests/bpf: add sleepable timer tests include/linux/bpf_verifier.h | 1 + include/uapi/linux/bpf.h | 4 + kernel/bpf/helpers.c | 132 ++++++++++++++++++++- kernel/bpf/verifier.c | 92 +++++++++++++- tools/include/uapi/linux/bpf.h | 4 + tools/testing/selftests/bpf/bpf_experimental.h | 4 + .../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 | 1 + tools/testing/selftests/bpf/progs/timer.c | 40 ++++++- tools/testing/selftests/bpf/progs/timer_failure.c | 114 +++++++++++++++++- 11 files changed, 387 insertions(+), 11 deletions(-) --- base-commit: 9187210eee7d87eea37b45ea93454a88681894a4 change-id: 20240205-hid-bpf-sleepable-c01260fd91c4 Best regards,