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. Daniel, thoughts?
