From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stanislav Fomichev Subject: Re: [PATCH bpf-next v2 0/6] skip verifier/map tests if kernel support is missing Date: Tue, 18 Dec 2018 13:30:13 -0800 Message-ID: <20181218213013.GD20955@mini-arch.hsd1.ca.comcast.net> References: <20181217182554.52170-1-sdf@google.com> <20181218212501.bw5qn3fae6snubze@ast-mbp> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Stanislav Fomichev , netdev@vger.kernel.org, ast@kernel.org, davem@davemloft.net, daniel@iogearbox.net, ecree@solarflare.com, quentin.monnet@netronome.com To: Alexei Starovoitov Return-path: Received: from mail-pg1-f193.google.com ([209.85.215.193]:35586 "EHLO mail-pg1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726850AbeLRVaP (ORCPT ); Tue, 18 Dec 2018 16:30:15 -0500 Received: by mail-pg1-f193.google.com with SMTP id s198so8405350pgs.2 for ; Tue, 18 Dec 2018 13:30:15 -0800 (PST) Content-Disposition: inline In-Reply-To: <20181218212501.bw5qn3fae6snubze@ast-mbp> Sender: netdev-owner@vger.kernel.org List-ID: 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. > Daniel, thoughts? >