On Mon, Jun 22, 2026 at 7:38 AM Leon Hwang <[email protected]> wrote: > > Since percpu_array supports direct-read, it should not break accessing
what does "it" refer to here? > rdonly percpu_array. > > Add a test to verify that adding '.map_direct_value_addr' to percpu_array > won't break the case. what case? I think you are testing (read-only) direct access to read-only per-CPU array, is that right? Just write that out? Though, really, negative test (we *cannot* access read-only per-cpu map for write operation) would be more trustworthy for this... > > Assisted-by: Codex:gpt-5.5-xhigh > Signed-off-by: Leon Hwang <[email protected]> > --- > .../bpf/prog_tests/global_data_init.c | 44 +++++++++++++++++++ > 1 file changed, 44 insertions(+) > > diff --git a/tools/testing/selftests/bpf/prog_tests/global_data_init.c > b/tools/testing/selftests/bpf/prog_tests/global_data_init.c > index ea7e4e3d91cf..f59d83919058 100644 > --- a/tools/testing/selftests/bpf/prog_tests/global_data_init.c > +++ b/tools/testing/selftests/bpf/prog_tests/global_data_init.c > @@ -232,6 +232,48 @@ static void test_global_percpu_data_lskel(void) > free(online); > } > > +static void test_global_percpu_data_rdonly_direct_read(void) > +{ > + LIBBPF_OPTS(bpf_map_create_opts, map_opts, > + .map_flags = BPF_F_RDONLY_PROG, > + ); > + struct bpf_insn insns[] = { > + BPF_ST_MEM(BPF_W, BPF_REG_10, -8, 0), > + BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), > + BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8), > + BPF_LD_MAP_FD(BPF_REG_1, 0), > + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, > BPF_FUNC_map_lookup_elem), > + BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 1), > + BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_0, 0), > + BPF_EXIT_INSN(), > + }; > + int key = 0, map_fd, prog_fd = -1, err; > + __u64 value = 0; > + > + map_fd = bpf_map_create(BPF_MAP_TYPE_PERCPU_ARRAY, "percpu_ro_map", > sizeof(int), > + sizeof(__u64), 1, &map_opts); > + if (!ASSERT_GE(map_fd, 0, "bpf_map_create")) > + return; > + > + err = bpf_map_update_elem(map_fd, &key, &value, BPF_F_ALL_CPUS); > + if (!ASSERT_OK(err, "bpf_map_update_elem")) > + goto out; > + > + err = bpf_map_freeze(map_fd); > + if (!ASSERT_OK(err, "bpf_map_freeze")) > + goto out; > + > + insns[3].imm = map_fd; > + prog_fd = bpf_prog_load(BPF_PROG_TYPE_SOCKET_FILTER, > "percpu_ro_prog", "GPL", insns, > + ARRAY_SIZE(insns), NULL); > + ASSERT_GE(prog_fd, 0, "bpf_prog_load"); > + > +out: > + if (prog_fd >= 0) > + close(prog_fd); > + close(map_fd); > +} > + > void test_global_percpu_data(void) > { > if (!feat_supported(NULL, FEAT_PERCPU_DATA)) { > @@ -243,4 +285,6 @@ void test_global_percpu_data(void) > test_global_percpu_data_init(); > if (test__start_subtest("lskel")) > test_global_percpu_data_lskel(); > + if (test__start_subtest("rdonly_direct_read")) > + test_global_percpu_data_rdonly_direct_read(); > } > -- > 2.54.0 >
