From patchwork Fri Mar 22 14:56:20 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Benjamin Tissoires X-Patchwork-Id: 13600224 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 5FA7C4AEC3; Fri, 22 Mar 2024 14:56:37 +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=1711119397; cv=none; b=WyqP529zbylFAe4PqOHOtVyLF46U7iFGYSk9DqRHZ1dmw1Gv06rtfNwD272OEylJCjhhVWrOCUB1dKnnCxDRg50auEtu0j5IP+u3rAaVcwBgrH/EltcxxZVtMe8f8U4npImC35SXkyzFamX+UqUyhR38gvmy5xVmCGWHbQWqXmA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711119397; c=relaxed/simple; bh=B3+9hbrYbOgrf7SwvZDCmpmOCm9dH1xA1Os15FGm0f8=; h=From:Subject:Date:Message-Id:MIME-Version:Content-Type:To:Cc; b=eJHXfFkKoUWzhyjQmwtrwNY9/LkSbYkZwkq2DolkRtoMrNY1mSJ0tkUvvPznKtFCtbBIKiRig+9EizqXzw8I1ihCjxThfATraBxiBgdim561arpwkKwiicP84KX4hKlKDnDiOYKtEiPQbM09Z9rC4LrPNgwHbiCbF9/eAix4cAM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=VZJKC1A3; 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="VZJKC1A3" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 79ABEC433C7; Fri, 22 Mar 2024 14:56:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1711119396; bh=B3+9hbrYbOgrf7SwvZDCmpmOCm9dH1xA1Os15FGm0f8=; h=From:Subject:Date:To:Cc:From; b=VZJKC1A3CVm0OJ8xGSmhf7SSk8nzq4ItyPvudRWKQcAsbfP2kX2NCu8epX4eQ1qfS 4V/psdDu2COTE58DgYi7ogHeR7OZutZrKv+sSEj4iAWkKilXihB76XauZP0wKo+4qo zusumbbZEdXVhIU8RYTLU93TVE3iAtarIOfyjAs/Elmdv0sFuomZwGIqufgCrJ78dA kz7qh/r7xIoxGp/rPgQ58a3dDYE5PFAee/UgEnkd3xuJkbLvyB7xkpFI+jpBpFzctp oE5DVLpSw5uf0qL1E6O5MpKylJQ2c2ysEMuVybKVlFRoObF6CFaU0mG+Au1FIImiLU vD7po2W+E+BXQ== From: Benjamin Tissoires Subject: [PATCH bpf-next v5 0/6] sleepable bpf_timer (was: allow HID-BPF to do device IOs) Date: Fri, 22 Mar 2024 15:56:20 +0100 Message-Id: <20240322-hid-bpf-sleepable-v5-0-179c7b59eaaa@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=H4sIABWc/WUC/23QzWrDMAwH8FcpPs/FH5KT7LT3KDvEttyYhSTYx bSUvPvcMFhLc/wj6SehO8uUImX2ebizRCXmOE814MeBuaGfzsSjr5kpoUAogXyIntsl8DwSLb0 diTshlRHBd9IBq3NLohCvm3lij9aJrhf2XStDzJc53bZlRW71P7fbcYvkgoNzbYcWe2/91w+li cbjnM4bV9QTIWGPUJXABo0VCI2Cd0I/EUruEboSMljdtK43Wsg3Av4JLfceVOBxhcE2KASBBl6 IdV1/AZNDiR2GAQAA 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=1711119393; l=4779; i=bentiss@kernel.org; s=20230215; h=from:subject:message-id; bh=B3+9hbrYbOgrf7SwvZDCmpmOCm9dH1xA1Os15FGm0f8=; b=N//ErnQ5quS/WeDbzudW1FZYPPK5FPfZ7IXc5QPNWx7ktW2p/aZcx+abWc1UC0QMDIoLZgln+ yWLKHjBtDREDMg+mMrYuQLaSUzLs8gO86c5qoxqUd6C8VUbZBfagj8h 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 indepandantly. 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 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 (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 | 96 ++++++++++- tools/include/uapi/linux/bpf.h | 4 + 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 | 185 +++++++++++++++++++++ 10 files changed, 458 insertions(+), 9 deletions(-) --- base-commit: 9187210eee7d87eea37b45ea93454a88681894a4 change-id: 20240205-hid-bpf-sleepable-c01260fd91c4 Best regards,