mbox series

[0/2] bpf: introduce helper for populating bpf_cpumask

Message ID 20250228003321.1409285-1-emil@etsalapatis.com (mailing list archive)
Headers show
Series bpf: introduce helper for populating bpf_cpumask | expand

Message

Emil Tsalapatis Feb. 28, 2025, 12:33 a.m. UTC 
Some BPF programs like scx schedulers have their own internal CPU mask types, 
mask types, which they must transform into struct bpf_cpumask instances
before passing them to scheduling-related kfuncs. There is currently no
way to efficiently populate the bitfield of a bpf_cpumask from BPF memory, 
and programs must use multiple bpf_cpumask_[set, clear] calls to do so. 
Introduce a kfunc helper to populate the bitfield of a bpf_cpumask from valid 
BPF memory with a single call.

Signed-off-by: Emil Tsalapatis (Meta) <emil@etsalapatis.com>

Emil Tsalapatis (2):
  bpf: add kfunc for populating cpumask bits
  selftests: bpf: add bpf_cpumask_fill selftests

 kernel/bpf/cpumask.c                          | 21 +++++
 .../selftests/bpf/prog_tests/verifier.c       |  2 +
 .../selftests/bpf/progs/cpumask_success.c     | 23 ++++++
 .../selftests/bpf/progs/verifier_cpumask.c    | 77 +++++++++++++++++++
 4 files changed, 123 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/progs/verifier_cpumask.c