Hi Stanislav, 2018-12-13 11:02 UTC-0800 ~ Stanislav Fomichev <s...@google.com> > Export bpf_map_type_supported() and bpf_prog_type_supported() which > return true/false to indicate kernel support for the appropriate > program or map type. These helpers will be used in the next commits > to selectively skip test_verifier/test_maps tests. > > bpf_map_type_supported() supports only limited set of maps for which we > do fixups in the test_verifier, for unknown maps it falls back to > 'supported'.
Why would you fall back on “supported” if it does not know about them? Would that be worth having an enum as a return type (..._SUPPORTED, ..._UNSUPPORTED, ..._UNKNOWN) maybe? Or default to not supported? Not related - We would need to put a warning somewhere, maybe a comment in the header, that using probes repeatedly in a short amount of time needs to update resources limits (setrlimit()), otherwise probes won't work correctly. > > Signed-off-by: Stanislav Fomichev <s...@google.com> > --- > tools/testing/selftests/bpf/probe_helpers.c | 68 +++++++++++++++++++++ > tools/testing/selftests/bpf/probe_helpers.h | 10 +++ > 2 files changed, 78 insertions(+) > create mode 100644 tools/testing/selftests/bpf/probe_helpers.c > create mode 100644 tools/testing/selftests/bpf/probe_helpers.h > > diff --git a/tools/testing/selftests/bpf/probe_helpers.c > b/tools/testing/selftests/bpf/probe_helpers.c > new file mode 100644 > index 000000000000..00467fdda813 > --- /dev/null > +++ b/tools/testing/selftests/bpf/probe_helpers.c > @@ -0,0 +1,68 @@ > +// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) > +#include <unistd.h> > +#include <bpf/bpf.h> > + > +#include "cgroup_helpers.h" > +#include "bpf_util.h" > +#include "../../../include/linux/filter.h" > + > +bool bpf_prog_type_supported(enum bpf_prog_type prog_type) Can we please make it possible to add an ifindex for testing offload support? > +{ > + struct bpf_load_program_attr attr; > + struct bpf_insn insns[] = { > + BPF_MOV64_IMM(BPF_REG_0, 0), > + BPF_EXIT_INSN(), > + }; > + int ret; > + > + if (prog_type == BPF_PROG_TYPE_UNSPEC) > + return true; > + > + memset(&attr, 0, sizeof(attr)); > + attr.prog_type = prog_type; > + attr.insns = insns; > + attr.insns_cnt = ARRAY_SIZE(insns); > + attr.license = "GPL"; > + > + ret = bpf_load_program_xattr(&attr, NULL, 0); > + if (ret < 0) > + return false; > + close(ret); > + > + return true; > +} > + > +bool bpf_map_type_supported(enum bpf_map_type map_type) Could we take an ifindex here as well? > +{ > + int key_size, value_size, max_entries; > + int fd; > + > + key_size = sizeof(__u32); > + value_size = sizeof(__u32); > + max_entries = 1; > + > + /* limited set of maps for test_verifier.c and test_maps.c */ > + switch (map_type) { > + case BPF_MAP_TYPE_SOCKMAP: > + case BPF_MAP_TYPE_SOCKHASH: > + case BPF_MAP_TYPE_XSKMAP: > + break; > + case BPF_MAP_TYPE_STACK_TRACE: > + value_size = sizeof(__u64); > + case BPF_MAP_TYPE_CGROUP_STORAGE: > + case BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE: > + key_size = sizeof(struct bpf_cgroup_storage_key); > + value_size = sizeof(__u64); > + max_entries = 0; > + break; > + default: Why not probing the other types of maps and blindly assume everything else is supported? > + return true; > + } For the record if you were to probe all existing map types at this date you have would have issues here for LPM_TRIE (key_size, value_size, map_flags), QUEUE and STACK (key_size). Also, maps in maps. > + > + fd = bpf_create_map(map_type, key_size, value_size, max_entries, 0); > + if (fd < 0) > + return false; > + close(fd); > + > + return true; > +} > diff --git a/tools/testing/selftests/bpf/probe_helpers.h > b/tools/testing/selftests/bpf/probe_helpers.h > new file mode 100644 > index 000000000000..9a107d6fe936 > --- /dev/null > +++ b/tools/testing/selftests/bpf/probe_helpers.h > @@ -0,0 +1,10 @@ > +/* SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) */ > +#ifndef __PROBE_HELPERS_H > +#define __PROBE_HELPERS_H > + > +#include <linux/bpf.h> > + > +bool bpf_prog_type_supported(enum bpf_prog_type prog_type); > +bool bpf_map_type_supported(enum bpf_map_type map_type); Should these get a visibility attribute with "LIBBPF_API" in front of the declarations? > + > +#endif