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From:   Krzesimir Nowak <krzesimir@kinvolk.io>
Date:   Fri, 12 Jul 2019 19:37:12 +0200
Message-ID: <CAGGp+cGMnumMx+GnKbD_ty1C+UWib70s0oBzqdS-=mA-L0jyHA@mail.gmail.com>
Subject: Re: [bpf-next v3 11/12] selftests/bpf: Add tests for
 bpf_prog_test_run for perf events progs
To:     Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc:     open list <linux-kernel@vger.kernel.org>,
        Alban Crequy <alban@kinvolk.io>,
        =?UTF-8?Q?Iago_L=C3=B3pez_Galeiras?= <iago@kinvolk.io>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Martin KaFai Lau <kafai@fb.com>,
        Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <jakub.kicinski@netronome.com>,
        Jesper Dangaard Brouer <hawk@kernel.org>,
        John Fastabend <john.fastabend@gmail.com>,
        Stanislav Fomichev <sdf@google.com>,
        Networking <netdev@vger.kernel.org>, bpf <bpf@vger.kernel.org>,
        xdp-newbies@vger.kernel.org
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On Fri, Jul 12, 2019 at 2:38 AM Andrii Nakryiko
<andrii.nakryiko@gmail.com> wrote:
>
> On Mon, Jul 8, 2019 at 3:42 PM Krzesimir Nowak <krzesimir@kinvolk.io> wro=
te:
> >
> > The tests check if ctx and data are correctly prepared from ctx_in and
> > data_in, so accessing the ctx and using the bpf_perf_prog_read_value
> > work as expected.
> >
>
> These are x86_64-specific tests, aren't they? Should probably guard
> them behind #ifdef's.

Yeah, they are x86_64 specific, because pt_regs are arch specific. I
was wondering what to do here in the cover letter. Ifdef? Ifdef and
cover also other arches (please no)? Do some weird tricks with
overriding the definition of pt_regs? Else?

>
> > Signed-off-by: Krzesimir Nowak <krzesimir@kinvolk.io>
> > ---
> >  tools/testing/selftests/bpf/test_verifier.c   | 48 ++++++++++
> >  .../selftests/bpf/verifier/perf_event_run.c   | 96 +++++++++++++++++++
> >  2 files changed, 144 insertions(+)
> >  create mode 100644 tools/testing/selftests/bpf/verifier/perf_event_run=
.c
> >
> > diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testin=
g/selftests/bpf/test_verifier.c
> > index 6f124cc4ee34..484ea8842b06 100644
> > --- a/tools/testing/selftests/bpf/test_verifier.c
> > +++ b/tools/testing/selftests/bpf/test_verifier.c
> > @@ -295,6 +295,54 @@ static void bpf_fill_scale(struct bpf_test *self)
> >         }
> >  }
> >
> > +static void bpf_fill_perf_event_test_run_check(struct bpf_test *self)
> > +{
> > +       compiletime_assert(
> > +               sizeof(struct bpf_perf_event_data) <=3D TEST_CTX_LEN,
> > +               "buffer for ctx is too short to fit struct bpf_perf_eve=
nt_data");
> > +       compiletime_assert(
> > +               sizeof(struct bpf_perf_event_value) <=3D TEST_DATA_LEN,
> > +               "buffer for data is too short to fit struct bpf_perf_ev=
ent_value");
> > +
> > +       struct bpf_perf_event_data ctx =3D {
> > +               .regs =3D (bpf_user_pt_regs_t) {
> > +                       .r15 =3D 1,
> > +                       .r14 =3D 2,
> > +                       .r13 =3D 3,
> > +                       .r12 =3D 4,
> > +                       .rbp =3D 5,
> > +                       .rbx =3D 6,
> > +                       .r11 =3D 7,
> > +                       .r10 =3D 8,
> > +                       .r9 =3D 9,
> > +                       .r8 =3D 10,
> > +                       .rax =3D 11,
> > +                       .rcx =3D 12,
> > +                       .rdx =3D 13,
> > +                       .rsi =3D 14,
> > +                       .rdi =3D 15,
> > +                       .orig_rax =3D 16,
> > +                       .rip =3D 17,
> > +                       .cs =3D 18,
> > +                       .eflags =3D 19,
> > +                       .rsp =3D 20,
> > +                       .ss =3D 21,
> > +               },
> > +               .sample_period =3D 1,
> > +               .addr =3D 2,
> > +       };
> > +       struct bpf_perf_event_value data =3D {
> > +               .counter =3D 1,
> > +               .enabled =3D 2,
> > +               .running =3D 3,
> > +       };
> > +
> > +       memcpy(self->ctx, &ctx, sizeof(ctx));
> > +       memcpy(self->data, &data, sizeof(data));
>
> Just curious, just assignment didn't work?
>
> > +       free(self->fill_insns);
> > +       self->fill_insns =3D NULL;
> > +}
> > +
> >  /* BPF_SK_LOOKUP contains 13 instructions, if you need to fix up maps =
*/
> >  #define BPF_SK_LOOKUP(func)                                           =
 \
> >         /* struct bpf_sock_tuple tuple =3D {} */                       =
   \
> > diff --git a/tools/testing/selftests/bpf/verifier/perf_event_run.c b/to=
ols/testing/selftests/bpf/verifier/perf_event_run.c
> > new file mode 100644
> > index 000000000000..3f877458a7f8
> > --- /dev/null
> > +++ b/tools/testing/selftests/bpf/verifier/perf_event_run.c
> > @@ -0,0 +1,96 @@
> > +#define PER_LOAD_AND_CHECK_PTREG(PT_REG_FIELD, VALUE)                 =
 \
> > +       PER_LOAD_AND_CHECK_CTX(offsetof(bpf_user_pt_regs_t, PT_REG_FIEL=
D), VALUE)
> > +#define PER_LOAD_AND_CHECK_EVENT(PED_FIELD, VALUE)                    =
 \
> > +       PER_LOAD_AND_CHECK_CTX(offsetof(struct bpf_perf_event_data, PED=
_FIELD), VALUE)
> > +#define PER_LOAD_AND_CHECK_CTX(OFFSET, VALUE)                         =
 \
> > +       PER_LOAD_AND_CHECK_64(BPF_REG_4, BPF_REG_1, OFFSET, VALUE)
> > +#define PER_LOAD_AND_CHECK_VALUE(PEV_FIELD, VALUE)                    =
 \
> > +       PER_LOAD_AND_CHECK_64(BPF_REG_7, BPF_REG_6, offsetof(struct bpf=
_perf_event_value, PEV_FIELD), VALUE)
>
> Wrap long lines? Try also running scripts/checkpatch.pl again these
> files you are modifying.

Will wrap. Checkpatch was also complaining about complex macro not
being inside parens, but I can't see how to wrap it in parens and keep
it working at the same time.

>
> > +#define PER_LOAD_AND_CHECK_64(DST, SRC, OFFSET, VALUE)                =
 \
> > +       BPF_LDX_MEM(BPF_DW, DST, SRC, OFFSET),                         =
 \
> > +       BPF_JMP_IMM(BPF_JEQ, DST, VALUE, 2),                           =
 \
> > +       BPF_MOV64_IMM(BPF_REG_0, VALUE),                               =
 \
> > +       BPF_EXIT_INSN()
> > +
> > +{
> > +       "check if regs contain expected values",
> > +       .insns =3D {
> > +       PER_LOAD_AND_CHECK_PTREG(r15, 1),
> > +       PER_LOAD_AND_CHECK_PTREG(r14, 2),
> > +       PER_LOAD_AND_CHECK_PTREG(r13, 3),
> > +       PER_LOAD_AND_CHECK_PTREG(r12, 4),
> > +       PER_LOAD_AND_CHECK_PTREG(rbp, 5),
> > +       PER_LOAD_AND_CHECK_PTREG(rbx, 6),
> > +       PER_LOAD_AND_CHECK_PTREG(r11, 7),
> > +       PER_LOAD_AND_CHECK_PTREG(r10, 8),
> > +       PER_LOAD_AND_CHECK_PTREG(r9, 9),
> > +       PER_LOAD_AND_CHECK_PTREG(r8, 10),
> > +       PER_LOAD_AND_CHECK_PTREG(rax, 11),
> > +       PER_LOAD_AND_CHECK_PTREG(rcx, 12),
> > +       PER_LOAD_AND_CHECK_PTREG(rdx, 13),
> > +       PER_LOAD_AND_CHECK_PTREG(rsi, 14),
> > +       PER_LOAD_AND_CHECK_PTREG(rdi, 15),
> > +       PER_LOAD_AND_CHECK_PTREG(orig_rax, 16),
> > +       PER_LOAD_AND_CHECK_PTREG(rip, 17),
> > +       PER_LOAD_AND_CHECK_PTREG(cs, 18),
> > +       PER_LOAD_AND_CHECK_PTREG(eflags, 19),
> > +       PER_LOAD_AND_CHECK_PTREG(rsp, 20),
> > +       PER_LOAD_AND_CHECK_PTREG(ss, 21),
> > +       BPF_MOV64_IMM(BPF_REG_0, 0),
> > +       BPF_EXIT_INSN(),
> > +       },
> > +       .result =3D ACCEPT,
> > +       .prog_type =3D BPF_PROG_TYPE_PERF_EVENT,
> > +       .ctx_len =3D sizeof(struct bpf_perf_event_data),
> > +       .data_len =3D sizeof(struct bpf_perf_event_value),
> > +       .fill_helper =3D bpf_fill_perf_event_test_run_check,
> > +       .override_data_out_len =3D true,
> > +},
> > +{
> > +       "check if sample period and addr contain expected values",
> > +       .insns =3D {
> > +       PER_LOAD_AND_CHECK_EVENT(sample_period, 1),
> > +       PER_LOAD_AND_CHECK_EVENT(addr, 2),
> > +       BPF_MOV64_IMM(BPF_REG_0, 0),
> > +       BPF_EXIT_INSN(),
> > +       },
> > +       .result =3D ACCEPT,
> > +       .prog_type =3D BPF_PROG_TYPE_PERF_EVENT,
> > +       .ctx_len =3D sizeof(struct bpf_perf_event_data),
> > +       .data_len =3D sizeof(struct bpf_perf_event_value),
> > +       .fill_helper =3D bpf_fill_perf_event_test_run_check,
> > +       .override_data_out_len =3D true,
> > +},
> > +{
> > +       "check if bpf_perf_prog_read_value returns expected data",
> > +       .insns =3D {
> > +       // allocate space for a struct bpf_perf_event_value
> > +       BPF_MOV64_REG(BPF_REG_6, BPF_REG_10),
> > +       BPF_ALU64_IMM(BPF_ADD, BPF_REG_6, -(int)sizeof(struct bpf_perf_=
event_value)),
> > +       // prepare parameters for bpf_perf_prog_read_value(ctx, struct =
bpf_perf_event_value*, u32)
> > +       // BPF_REG_1 already contains the context
> > +       BPF_MOV64_REG(BPF_REG_2, BPF_REG_6),
> > +       BPF_MOV64_IMM(BPF_REG_3, sizeof(struct bpf_perf_event_value)),
> > +       BPF_EMIT_CALL(BPF_FUNC_perf_prog_read_value),
> > +       // check the return value
> > +       BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 1),
> > +       BPF_EXIT_INSN(),
> > +       // check if the fields match the expected values
>
> Use /* */ comments.

Oops. Will fix.

>
> > +       PER_LOAD_AND_CHECK_VALUE(counter, 1),
> > +       PER_LOAD_AND_CHECK_VALUE(enabled, 2),
> > +       PER_LOAD_AND_CHECK_VALUE(running, 3),
> > +       BPF_MOV64_IMM(BPF_REG_0, 0),
> > +       BPF_EXIT_INSN(),
> > +       },
> > +       .result =3D ACCEPT,
> > +       .prog_type =3D BPF_PROG_TYPE_PERF_EVENT,
> > +       .ctx_len =3D sizeof(struct bpf_perf_event_data),
> > +       .data_len =3D sizeof(struct bpf_perf_event_value),
> > +       .fill_helper =3D bpf_fill_perf_event_test_run_check,
> > +       .override_data_out_len =3D true,
> > +},
> > +#undef PER_LOAD_AND_CHECK_64
> > +#undef PER_LOAD_AND_CHECK_VALUE
> > +#undef PER_LOAD_AND_CHECK_CTX
> > +#undef PER_LOAD_AND_CHECK_EVENT
> > +#undef PER_LOAD_AND_CHECK_PTREG
> > --
> > 2.20.1
> >


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