On 12/18/2018 10:30 PM, Stanislav Fomichev wrote: > On 12/18, Alexei Starovoitov wrote: >> On Mon, Dec 17, 2018 at 10:25:48AM -0800, Stanislav Fomichev wrote: >>> If test_maps/test_verifier is running against the kernel which doesn't >>> have _all_ BPF features enabled, it fails with an error. This patch >>> series tries to probe kernel support for each failed test and skip >>> it instead. This lets users run BPF selftests in the not-all-bpf-yes >>> environments and received correct PASS/NON-PASS result. >>> >>> See https://www.spinics.net/lists/netdev/msg539331.html for more >>> context. >>> >>> The series goes like this: >>> >>> * patch #1 adds bpf_prog_type_supported() and >>> bpf_map_type_supported() which query the kernel (insert 'return 0' >>> program or try to create empty map with correct key/value sizes) and >>> return supported/unsupported. >>> Note: this functionality can later be reimplemented on top of Quentin's >>> recent 'bpftool feature' patchset if he decides to move the probes >>> into libbpf. >>> * patch #2 skips sockmap tests in test_maps.c if BPF_MAP_TYPE_SOCKMAP >>> map is not supported (if bpf_create_map fails, we probe the kernel >>> for support) >>> * patch #3 skips verifier tests if test->prog_type is not supported (if >>> bpf_verify_program fails, we probe the kernel for support) >>> * patch #4 skips verifier tests if test fixup map is not supported (if >>> create_map fails, we probe the kernel for support) >>> Note: we can probably move this probe into create_map helper and >>> return some argument instead of adding skip_unsupported_map() >>> to each fixup; but I'm not sure it's better. >>> Also note: in current implementation we still print 'Failed to >>> create hash map' from the create_map, but still skip the test. >>> * next patches fix various small issues that arise from the first four: >>> * patch #5 sets "unknown func bpf_trace_printk#6" prog_type to >>> BPF_PROG_TYPE_TRACEPOINT so it is correctly skipped in >>> CONFIG_BPF_EVENTS=n case >>> * patch #6 exposes BPF_PROG_TYPE_CGROUP_{SKB,SOCK,SOCK_ADDR} only when >>> CONFIG_CGROUP_BPF=y, this makes verifier correctly skip appropriate >>> tests >>> >>> v2 changes: >>> >>> * don't sprinkle "ifdef CONFIG_CGROUP_BPF" all around net/core/filter.c, >>> doing it only in the bpf_types.h is enough to disable >>> BPF_PROG_TYPE_CGROUP_{SKB,SOCK,SOCK_ADDR} prog types for non-cgroup >>> enabled kernels >> >> the patches look good to me. >> I think it's ok to proceed this way though long term we probably >> want to have such bpf_prog_type_supported() to be part of libbpf >> and reused in test_verifier.c and in bpftool. > Quentin is working on adding more generic bpf_xyz_type_supported() to > libbpf. My plan is to switch to them as soon as they are merged.
Yeah, libbpf probes in-tree user for BPF kselftest sounds good to me. >> Daniel, thoughts? I just have few minor nits; will reply in a sec to the two patches, but it's nothing blocking the series here. Thanks, Daniel
