Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Song Liu <songliubraving@fb.com>
To:     Andrii Nakryiko <andrii.nakryiko@gmail.com>
CC:     open list <linux-kernel@vger.kernel.org>,
        bpf <bpf@vger.kernel.org>, Networking <netdev@vger.kernel.org>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Kernel Team <Kernel-team@fb.com>,
        john fastabend <john.fastabend@gmail.com>,
        KP Singh <kpsingh@chromium.org>,
        Jesper Dangaard Brouer <brouer@redhat.com>,
        Daniel Xu <dlxu@fb.com>
Subject: Re: [PATCH bpf-next 3/5] selftests/bpf: add selftest for
 BPF_PROG_TYPE_USER
Thread-Topic: [PATCH bpf-next 3/5] selftests/bpf: add selftest for
 BPF_PROG_TYPE_USER
Thread-Index: AQHWZ+C38TtsngeYdEmidjk+2G1vlqkln1aAgAAvdIA=
Date:   Mon, 3 Aug 2020 04:33:45 +0000
Message-ID: <C5606E9B-D3EC-4425-82F5-DA5865836D3E@fb.com>
References: <20200801084721.1812607-1-songliubraving@fb.com>
 <20200801084721.1812607-4-songliubraving@fb.com>
 <CAEf4BzazkFMw3LAs3M2hxSLWWZJ7ywykwte=0WDhC1zgMYw-3A@mail.gmail.com>
In-Reply-To: <CAEf4BzazkFMw3LAs3M2hxSLWWZJ7ywykwte=0WDhC1zgMYw-3A@mail.gmail.com>
Accept-Language: en-US
Content-Language: en-US
Content-Type: text/plain; charset="us-ascii"
Content-ID: <14C719EDB93DB448ABFB99E92828758C@namprd15.prod.outlook.com>
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
X-MS-Exchange-CrossTenant-Network-Message-Id: dbbd6077-bb0a-4794-28b3-08d8376668c8
X-MS-Exchange-CrossTenant-originalarrivaltime: 03 Aug 2020 04:33:45.5665
 (UTC)
X-MS-Exchange-CrossTenant-fromentityheader: Hosted
X-MS-Exchange-CrossTenant-id: 8ae927fe-1255-47a7-a2af-5f3a069daaa2
X-MS-Exchange-CrossTenant-mailboxtype: HOSTED
X-MS-Exchange-CrossTenant-userprincipalname: lilT/XxfkCfXt38GLtd+3eCbTWDlQs0xtRndP8ToOynIhHvuIxrkkWCh0oTeZf5xeedvYF3TxmaD4HcE9LLWeA==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: BYAPR15MB3095
X-OriginatorOrg: fb.com
X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235,18.0.687
 definitions=2020-08-03_01:2020-07-31,2020-08-03 signatures=0
X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 malwarescore=0
 phishscore=0 clxscore=1015 adultscore=0 bulkscore=0 mlxlogscore=999
 suspectscore=0 mlxscore=0 spamscore=0 priorityscore=1501
 lowpriorityscore=0 impostorscore=0 classifier=spam adjust=0 reason=mlx
 scancount=1 engine=8.12.0-2006250000 definitions=main-2008030032
X-FB-Internal: deliver
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org


> On Aug 2, 2020, at 6:43 PM, Andrii Nakryiko <andrii.nakryiko@gmail.com> w=
rote:
>=20
> On Sat, Aug 1, 2020 at 1:50 AM Song Liu <songliubraving@fb.com> wrote:
>>=20
>> This test checks the correctness of BPF_PROG_TYPE_USER program, includin=
g:
>> running on the right cpu, passing in correct args, returning retval, and
>> being able to call bpf_get_stack|stackid.
>>=20
>> Signed-off-by: Song Liu <songliubraving@fb.com>
>> ---
>> .../selftests/bpf/prog_tests/user_prog.c      | 52 +++++++++++++++++
>> tools/testing/selftests/bpf/progs/user_prog.c | 56 +++++++++++++++++++
>> 2 files changed, 108 insertions(+)
>> create mode 100644 tools/testing/selftests/bpf/prog_tests/user_prog.c
>> create mode 100644 tools/testing/selftests/bpf/progs/user_prog.c
>>=20
>> diff --git a/tools/testing/selftests/bpf/prog_tests/user_prog.c b/tools/=
testing/selftests/bpf/prog_tests/user_prog.c
>> new file mode 100644
>> index 0000000000000..416707b3bff01
>> --- /dev/null
>> +++ b/tools/testing/selftests/bpf/prog_tests/user_prog.c
>> @@ -0,0 +1,52 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/* Copyright (c) 2020 Facebook */
>> +#include <test_progs.h>
>> +#include "user_prog.skel.h"
>> +
>> +static int duration;
>> +
>> +void test_user_prog(void)
>> +{
>> +       struct bpf_user_prog_args args =3D {{0, 1, 2, 3, 4}};
>> +       struct bpf_prog_test_run_attr attr =3D {};
>> +       struct user_prog *skel;
>> +       int i, numcpu, ret;
>> +
>> +       skel =3D user_prog__open_and_load();
>> +
>> +       if (CHECK(!skel, "user_prog__open_and_load",
>> +                 "skeleton open_and_laod failed\n"))
>> +               return;
>> +
>> +       numcpu =3D libbpf_num_possible_cpus();
>=20
> nit: possible doesn't mean online right now, so it will fail on
> offline or non-present CPUs

Just found parse_cpu_mask_file(), will use it to fix this.=20

[...]

>> +
>> +volatile int cpu_match =3D 1;
>> +volatile __u64 sum =3D 1;
>> +volatile int get_stack_success =3D 0;
>> +volatile int get_stackid_success =3D 0;
>> +volatile __u64 stacktrace[PERF_MAX_STACK_DEPTH];
>=20
> nit: no need for volatile for non-static variables
>=20
>> +
>> +SEC("user")
>> +int user_func(struct bpf_user_prog_ctx *ctx)
>=20
> If you put args in bpf_user_prog_ctx as a first field, you should be
> able to re-use the BPF_PROG macro to access those arguments in a more
> user-friendly way.

I am not sure I am following here. Do you mean something like:

struct bpf_user_prog_ctx {
        __u64 args[BPF_USER_PROG_MAX_ARGS];
        struct pt_regs *regs;
};

(swap args and regs)?=20

Thanks,
Song