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Miller" , Jakub Kicinski , Jesper Dangaard Brouer , John Fastabend , Stanislav Fomichev , netdev@vger.kernel.org, bpf@vger.kernel.org, xdp-newbies@vger.kernel.org Subject: Re: [bpf-next v3 10/12] bpf: Implement bpf_prog_test_run for perf event programs Message-ID: <20190711203059.GB16709@mini-arch> References: <20190708163121.18477-1-krzesimir@kinvolk.io> <20190708163121.18477-11-krzesimir@kinvolk.io> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190708163121.18477-11-krzesimir@kinvolk.io> User-Agent: Mutt/1.12.1 (2019-06-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/08, Krzesimir Nowak wrote: > As an input, test run for perf event program takes struct > bpf_perf_event_data as ctx_in and struct bpf_perf_event_value as > data_in. For an output, it basically ignores ctx_out and data_out. > > The implementation sets an instance of struct bpf_perf_event_data_kern > in such a way that the BPF program reading data from context will > receive what we passed to the bpf prog test run in ctx_in. Also BPF > program can call bpf_perf_prog_read_value to receive what was passed > in data_in. > > Changes since v2: > - drop the changes in perf event verifier test - they are not needed > anymore after reworked ctx size handling > > Signed-off-by: Krzesimir Nowak > --- > kernel/trace/bpf_trace.c | 60 ++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 60 insertions(+) > > diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c > index ca1255d14576..b870fc2314d0 100644 > --- a/kernel/trace/bpf_trace.c > +++ b/kernel/trace/bpf_trace.c > @@ -19,6 +19,8 @@ > #include "trace_probe.h" > #include "trace.h" > > +#include > + > #define bpf_event_rcu_dereference(p) \ > rcu_dereference_protected(p, lockdep_is_held(&bpf_event_mutex)) > > @@ -1160,7 +1162,65 @@ const struct bpf_verifier_ops perf_event_verifier_ops = { > .convert_ctx_access = pe_prog_convert_ctx_access, > }; > > +static int pe_prog_test_run(struct bpf_prog *prog, > + const union bpf_attr *kattr, > + union bpf_attr __user *uattr) > +{ > + struct bpf_perf_event_data_kern real_ctx = {0, }; > + struct perf_sample_data sample_data = {0, }; > + struct bpf_perf_event_data *fake_ctx; > + struct bpf_perf_event_value *value; > + struct perf_event event = {0, }; > + u32 retval = 0, duration = 0; > + int err; > + > + if (kattr->test.data_size_out || kattr->test.data_out) > + return -EINVAL; > + if (kattr->test.ctx_size_out || kattr->test.ctx_out) > + return -EINVAL; > + > + fake_ctx = bpf_receive_ctx(kattr, sizeof(struct bpf_perf_event_data)); > + if (IS_ERR(fake_ctx)) > + return PTR_ERR(fake_ctx); > + > + value = bpf_receive_data(kattr, sizeof(struct bpf_perf_event_value)); > + if (IS_ERR(value)) { > + kfree(fake_ctx); > + return PTR_ERR(value); > + } nit: maybe use bpf_test_ prefix for receive_ctx/data: * bpf_test_receive_ctx * bpf_test_receive_data ? To signify that they are used for tests only. > + > + real_ctx.regs = &fake_ctx->regs; > + real_ctx.data = &sample_data; > + real_ctx.event = &event; > + perf_sample_data_init(&sample_data, fake_ctx->addr, > + fake_ctx->sample_period); > + event.cpu = smp_processor_id(); > + event.oncpu = -1; > + event.state = PERF_EVENT_STATE_OFF; > + local64_set(&event.count, value->counter); > + event.total_time_enabled = value->enabled; > + event.total_time_running = value->running; > + /* make self as a leader - it is used only for checking the > + * state field > + */ > + event.group_leader = &event; > + err = bpf_test_run(prog, &real_ctx, kattr->test.repeat, > + BPF_TEST_RUN_PLAIN, &retval, &duration); > + if (err) { > + kfree(value); > + kfree(fake_ctx); > + return err; > + } > + > + err = bpf_test_finish(uattr, retval, duration); > + trace_bpf_test_finish(&err); Can probably do: err = bpf_test_run(...) if (!err) { err = bpf_test_finish(uattr, retval, duration); trace_bpf_test_finish(&err); } kfree(..); kfree(..); return err; So you don't have to copy-paste the error handling. > + kfree(value); > + kfree(fake_ctx); > + return err; > +} > + > const struct bpf_prog_ops perf_event_prog_ops = { > + .test_run = pe_prog_test_run, > }; > > static DEFINE_MUTEX(bpf_event_mutex); > -- > 2.20.1 >