| Message ID | 20240315-b4-hid-bpf-new-funcs-v4-0-079c282469d3@kernel.org (mailing list archive) |
|---|---|
| Headers | show |
| Series | Extend HID-BPF kfuncs (was: allow HID-BPF to do device IOs) | expand |
On Fri, 15 Mar 2024 15:44:37 +0100, Benjamin Tissoires wrote: > New version of the sleepable bpf_timer code, without BPF changes, as > they can now go through the HID tree independantly: > > https://lore.kernel.org/all/20240315-hid-bpf-sleepable-v4-0-5658f2540564@kernel.org/ > > For reference, the use cases I have in mind: > > [...] Applied to hid/hid.git (for-6.10/hid-bpf), thanks! [1/7] HID: bpf/dispatch: regroup kfuncs definitions https://git.kernel.org/hid/hid/c/4171954f56fb [2/7] HID: bpf: export hid_hw_output_report as a BPF kfunc https://git.kernel.org/hid/hid/c/5599f8019661 [3/7] selftests/hid: add KASAN to the VM tests https://git.kernel.org/hid/hid/c/c8a1495947ff [4/7] selftests/hid: Add test for hid_bpf_hw_output_report https://git.kernel.org/hid/hid/c/db624e82c55f [5/7] HID: bpf: allow to inject HID event from BPF https://git.kernel.org/hid/hid/c/9be50ac30a83 [6/7] selftests/hid: add tests for hid_bpf_input_report https://git.kernel.org/hid/hid/c/2c0e8ced7d4b [7/7] HID: bpf: allow to use bpf_timer_set_sleepable_cb() in tracing callbacks. https://git.kernel.org/hid/hid/c/685dadafbde2 Cheers,
New version of the sleepable bpf_timer code, without BPF changes, as they can now go through the HID tree independantly: https://lore.kernel.org/all/20240315-hid-bpf-sleepable-v4-0-5658f2540564@kernel.org/ 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: Jiri Kosina <jikos@kernel.org> To: Benjamin Tissoires <benjamin.tissoires@redhat.com> To: Jonathan Corbet <corbet@lwn.net> To: Shuah Khan <shuah@kernel.org> Cc: Benjamin Tissoires <bentiss@kernel.org> Cc: <linux-input@vger.kernel.org> Cc: <linux-kernel@vger.kernel.org> Cc: <bpf@vger.kernel.org> Cc: <linux-doc@vger.kernel.org> Cc: <linux-kselftest@vger.kernel.org> --- Changes in v4: - dropped the BPF changes, they can go independently in bpf-core - dropped the HID-BPF integration tests with the sleppable timers, I'll re-add them once both series (this and sleepable timers) are merged - 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 (7): HID: bpf/dispatch: regroup kfuncs definitions HID: bpf: export hid_hw_output_report as a BPF kfunc selftests/hid: add KASAN to the VM tests 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. Documentation/hid/hid-bpf.rst | 2 +- drivers/hid/bpf/hid_bpf_dispatch.c | 226 ++++++++++++++------- drivers/hid/hid-core.c | 2 + include/linux/hid_bpf.h | 3 + tools/testing/selftests/hid/config.common | 1 + tools/testing/selftests/hid/hid_bpf.c | 112 +++++++++- tools/testing/selftests/hid/progs/hid.c | 46 +++++ .../testing/selftests/hid/progs/hid_bpf_helpers.h | 6 + 8 files changed, 324 insertions(+), 74 deletions(-) --- base-commit: 3e78a6c0d3e02e4cf881dc84c5127e9990f939d6 change-id: 20240314-b4-hid-bpf-new-funcs-ecf05d0ef870 Best regards,