Re: [PATCH bpf-next v7 00/24] Introduce eBPF support for HID devices

Tero Kristo
2022-08-03T07:42:35Z

Hello,

Tried this out with my USI support eBPF code, and it works fine with the
single patch I had to apply on top of i2c-hid (not related to the
hid-bpf support itself.)

For the whole series:

Tested-by: Tero Kristo <tero.kristo@linux.intel.com>

-Tero

On 21/07/2022 18:36, Benjamin Tissoires wrote:
> Hi,
>
> here comes the v7 of the HID-BPF series.
>
> Again, for a full explanation of HID-BPF, please refer to the last patch
> in this series (24/24).
>
> This version sees some minor improvements compared to v6, only
> focusing on the reviews I got.
>
> I also wanted to mention that I have started working on the userspace
> side to "see" how the BPF programs would look when automatically loaded.
> See the udev-hid-bpf project[0] for the code.
>
> The idea is to define the HID-BPF userspace programs so we can reuse
> the same semantic in the kernel.
> I am quite happy with the results: this looks pretty similar to a kernel
> module in term of design. The .bpf.c file is a standalone compilation
> unit, and instead of having a table of ids, the filename is used (based
> on the modalias). This allows to have a "probe" like function that we
> can run to decide if the program needs to be attached or not.
>
> All in all, the end result is that we can write the bpf program, compile
> it locally, and send the result to the user. The user needs to drop the
> .bpf.o in a local folder, and udev-hid-bpf will pick it up the next time
> the device is plugged in. No other operations is required.
>
> Next step will be to drop the same source file in the kernel source
> tree, and have some magic to automatically load the compiled program
> when the device is loaded.
>
> Cheers,
> Benjamin
>
> [0] https://gitlab.freedesktop.org/bentiss/udev-hid-bpf (warning: probably
> not the best rust code ever)
>
> Benjamin Tissoires (24):
> selftests/bpf: fix config for CLS_BPF
> bpf/verifier: allow kfunc to read user provided context
> bpf/verifier: do not clear meta in check_mem_size
> selftests/bpf: add test for accessing ctx from syscall program type
> bpf/verifier: allow kfunc to return an allocated mem
> selftests/bpf: Add tests for kfunc returning a memory pointer
> bpf: prepare for more bpf syscall to be used from kernel and user
> space.
> libbpf: add map_get_fd_by_id and map_delete_elem in light skeleton
> HID: core: store the unique system identifier in hid_device
> HID: export hid_report_type to uapi
> HID: convert defines of HID class requests into a proper enum
> HID: Kconfig: split HID support and hid-core compilation
> HID: initial BPF implementation
> selftests/bpf: add tests for the HID-bpf initial implementation
> HID: bpf: allocate data memory for device_event BPF programs
> selftests/bpf/hid: add test to change the report size
> HID: bpf: introduce hid_hw_request()
> selftests/bpf: add tests for bpf_hid_hw_request
> HID: bpf: allow to change the report descriptor
> selftests/bpf: add report descriptor fixup tests
> selftests/bpf: Add a test for BPF_F_INSERT_HEAD
> samples/bpf: add new hid_mouse example
> HID: bpf: add Surface Dial example
> Documentation: add HID-BPF docs
>
> Documentation/hid/hid-bpf.rst | 512 +++++++++
> Documentation/hid/index.rst | 1 +
> drivers/Makefile | 2 +-
> drivers/hid/Kconfig | 20 +-
> drivers/hid/Makefile | 2 +
> drivers/hid/bpf/Kconfig | 18 +
> drivers/hid/bpf/Makefile | 11 +
> drivers/hid/bpf/entrypoints/Makefile | 93 ++
> drivers/hid/bpf/entrypoints/README | 4 +
> drivers/hid/bpf/entrypoints/entrypoints.bpf.c | 66 ++
> .../hid/bpf/entrypoints/entrypoints.lskel.h | 682 ++++++++++++
> drivers/hid/bpf/hid_bpf_dispatch.c | 553 ++++++++++
> drivers/hid/bpf/hid_bpf_dispatch.h | 28 +
> drivers/hid/bpf/hid_bpf_jmp_table.c | 577 ++++++++++
> drivers/hid/hid-core.c | 49 +-
> include/linux/bpf.h | 9 +-
> include/linux/btf.h | 10 +
> include/linux/hid.h | 38 +-
> include/linux/hid_bpf.h | 148 +++
> include/uapi/linux/hid.h | 26 +-
> include/uapi/linux/hid_bpf.h | 25 +
> kernel/bpf/btf.c | 91 +-
> kernel/bpf/syscall.c | 10 +-
> kernel/bpf/verifier.c | 65 +-
> net/bpf/test_run.c | 23 +
> samples/bpf/.gitignore | 2 +
> samples/bpf/Makefile | 27 +
> samples/bpf/hid_mouse.bpf.c | 134 +++
> samples/bpf/hid_mouse.c | 147 +++
> samples/bpf/hid_surface_dial.bpf.c | 161 +++
> samples/bpf/hid_surface_dial.c | 212 ++++
> tools/include/uapi/linux/hid.h | 62 ++
> tools/include/uapi/linux/hid_bpf.h | 25 +
> tools/lib/bpf/skel_internal.h | 23 +
> tools/testing/selftests/bpf/Makefile | 5 +-
> tools/testing/selftests/bpf/config | 5 +-
> tools/testing/selftests/bpf/prog_tests/hid.c | 990 ++++++++++++++++++
> .../selftests/bpf/prog_tests/kfunc_call.c | 76 ++
> tools/testing/selftests/bpf/progs/hid.c | 206 ++++
> .../selftests/bpf/progs/kfunc_call_test.c | 125 +++
> 40 files changed, 5184 insertions(+), 79 deletions(-)
> create mode 100644 Documentation/hid/hid-bpf.rst
> create mode 100644 drivers/hid/bpf/Kconfig
> create mode 100644 drivers/hid/bpf/Makefile
> create mode 100644 drivers/hid/bpf/entrypoints/Makefile
> create mode 100644 drivers/hid/bpf/entrypoints/README
> create mode 100644 drivers/hid/bpf/entrypoints/entrypoints.bpf.c
> create mode 100644 drivers/hid/bpf/entrypoints/entrypoints.lskel.h
> create mode 100644 drivers/hid/bpf/hid_bpf_dispatch.c
> create mode 100644 drivers/hid/bpf/hid_bpf_dispatch.h
> create mode 100644 drivers/hid/bpf/hid_bpf_jmp_table.c
> create mode 100644 include/linux/hid_bpf.h
> create mode 100644 include/uapi/linux/hid_bpf.h
> create mode 100644 samples/bpf/hid_mouse.bpf.c
> create mode 100644 samples/bpf/hid_mouse.c
> create mode 100644 samples/bpf/hid_surface_dial.bpf.c
> create mode 100644 samples/bpf/hid_surface_dial.c
> create mode 100644 tools/include/uapi/linux/hid.h
> create mode 100644 tools/include/uapi/linux/hid_bpf.h
> create mode 100644 tools/testing/selftests/bpf/prog_tests/hid.c
> create mode 100644 tools/testing/selftests/bpf/progs/hid.c
>