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[176.36.0.241]) by smtp.gmail.com with ESMTPSA id z23-20020a2e9657000000b002d295828d3fsm767386ljh.9.2024.03.01.17.19.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 01 Mar 2024 17:19:34 -0800 (PST) From: Eduard Zingerman To: bpf@vger.kernel.org, ast@kernel.org Cc: andrii@kernel.org, daniel@iogearbox.net, martin.lau@linux.dev, kernel-team@fb.com, yonghong.song@linux.dev, void@manifault.com, sinquersw@gmail.com, Eduard Zingerman Subject: [PATCH bpf-next v2 00/15] libbpf: type suffixes and autocreate flag for struct_ops maps Date: Sat, 2 Mar 2024 03:19:05 +0200 Message-ID: <20240302011920.15302-1-eddyz87@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: bpf@iogearbox.net Tweak struct_ops related APIs to allow the following features: - specify version suffixes for stuct_ops map types; - share same BPF program between several map definitions with different local BTF types, assuming only maps with same kernel BTF type would be selected for load; - toggle autocreate flag for struct_ops maps; - automatically toggle autoload for struct_ops programs referenced from struct_ops maps, depending on autocreate status of the corresponding map; - use SEC("?.struct_ops") and SEC("?.struct_ops.link") to define struct_ops maps with autocreate == false after object open. This would allow loading programs like below: SEC("struct_ops/foo") int BPF_PROG(foo) { ... } SEC("struct_ops/bar") int BPF_PROG(bar) { ... } struct bpf_testmod_ops___v1 { int (*foo)(void); }; struct bpf_testmod_ops___v2 { int (*foo)(void); int (*bar)(void); }; /* Assume kernel type name to be 'test_ops' */ SEC(".struct_ops.link") struct test_ops___v1 map_v1 = { /* Program 'foo' shared by maps with * different local BTF type */ .foo = (void *)foo }; SEC(".struct_ops.link") struct test_ops___v2 map_v2 = { .foo = (void *)foo, .bar = (void *)bar }; Assuming the following tweaks are done before loading: /* to load v1 */ bpf_map__set_autocreate(skel->maps.map_v1, true); bpf_map__set_autocreate(skel->maps.map_v2, false); /* to load v2 */ bpf_map__set_autocreate(skel->maps.map_v1, false); bpf_map__set_autocreate(skel->maps.map_v2, true); Patch #8 ties autocreate and autoload flags for struct_ops maps and programs. While discussion for v1 concluded that such feature is useful, it is an outlier compared to the rest of libbpf API that treats autoload / autocreate flags in most simple way possible. An alternative might be a dedicated API call, e.g.: int bpf_object__infer_struct_ops_progs_autoload(struct bpf_object *) That would set programs autoload flags depending on user defined state of autocreate flags of struct_ops map. It might even be accompanied by an API call: int bpf_object__infer_struct_ops_maps_autocreate(struct bpf_object *) That would check which struct_ops maps definitions could be loaded with current kernel, or report error if there are ambiguities. Changelog: - v1 [1] -> v2: - fixed memory leak in patch #1 (Kui-Feng); - improved error messages in patch #2 (Martin, Andrii); - in bad_struct_ops selftest from patch #6 added .test_2 map member setup (David); - added utility functions to capture libbpf log from selftests (David) - in selftests replaced usage of ...__open_and_load by separate calls to ..._open() and ..._load() (Andrii); - removed serial_... in selftest definitions (Andrii); - improved comments in selftest struct_ops_autocreate from patch #7 (David); - removed autoload toggling logic incompatible with shadow variables from bpf_map__set_autocreate(), instead struct_ops programs autoload property is computed at struct_ops maps load phase, see patch #8 (Kui-Feng, Martin, Andrii); - added support for SEC("?.struct_ops") and SEC("?.struct_ops.link") (Andrii). [1] https://lore.kernel.org/bpf/20240227204556.17524-1-eddyz87@gmail.com/ Eduard Zingerman (15): libbpf: allow version suffixes (___smth) for struct_ops types libbpf: tie struct_ops programs to kernel BTF ids, not to local ids libbpf: honor autocreate flag for struct_ops maps selftests/bpf: test struct_ops map definition with type suffix selftests/bpf: utility functions to capture libbpf log in test_progs selftests/bpf: bad_struct_ops test selftests/bpf: test autocreate behavior for struct_ops maps libbpf: sync progs autoload with maps autocreate for struct_ops maps selftests/bpf: verify struct_ops autoload/autocreate sync libbpf: replace elf_state->st_ops_* fields with SEC_ST_OPS sec_type libbpf: struct_ops in SEC("?.struct_ops") and SEC("?.struct_ops.link") libbpf: rewrite btf datasec names starting from '?' selftests/bpf: test case for SEC("?.struct_ops") bpf: allow '?' at the beginning of DATASEC names selftests/bpf: test cases for '?' in BTF names kernel/bpf/btf.c | 17 +- tools/lib/bpf/features.c | 22 +++ tools/lib/bpf/libbpf.c | 174 ++++++++++++------ tools/lib/bpf/libbpf_internal.h | 2 + .../selftests/bpf/bpf_testmod/bpf_testmod.c | 25 +++ .../selftests/bpf/bpf_testmod/bpf_testmod.h | 4 + .../selftests/bpf/prog_tests/bad_struct_ops.c | 67 +++++++ tools/testing/selftests/bpf/prog_tests/btf.c | 46 +++++ .../bpf/prog_tests/struct_ops_autocreate.c | 124 +++++++++++++ .../bpf/prog_tests/test_struct_ops_module.c | 33 +++- .../selftests/bpf/progs/bad_struct_ops.c | 25 +++ .../selftests/bpf/progs/bad_struct_ops2.c | 14 ++ .../bpf/progs/struct_ops_autocreate.c | 52 ++++++ .../selftests/bpf/progs/struct_ops_module.c | 21 ++- tools/testing/selftests/bpf/test_progs.c | 57 ++++++ tools/testing/selftests/bpf/test_progs.h | 3 + 16 files changed, 614 insertions(+), 72 deletions(-) create mode 100644 tools/testing/selftests/bpf/prog_tests/bad_struct_ops.c create mode 100644 tools/testing/selftests/bpf/prog_tests/struct_ops_autocreate.c create mode 100644 tools/testing/selftests/bpf/progs/bad_struct_ops.c create mode 100644 tools/testing/selftests/bpf/progs/bad_struct_ops2.c create mode 100644 tools/testing/selftests/bpf/progs/struct_ops_autocreate.c