[PATCH v2 bpf-next 0/3] enable BPF_PROG_TEST_RUN for raw_tp

[PATCH v2 bpf-next 0/3] enable BPF_PROG_TEST_RUN for raw_tp

[Song Liu]

This set enables BPF_PROG_TEST_RUN for raw_tracepoint type programs. This
set also enables running the raw_tp program on a specific CPU. This feature
can be used by user space to trigger programs that access percpu resources,
e.g. perf_event, percpu variables.

Changes v1 => v2:
1. More checks for retval in the selftest. (John)
2. Remove unnecessary goto in bpf_prog_test_run_raw_tp. (John)

Song Liu (3):
  bpf: enable BPF_PROG_TEST_RUN for raw_tracepoint
  libbpf: introduce bpf_prog_test_run_xattr_opts
  selftests/bpf: add raw_tp_test_run

 include/linux/bpf.h                           |  3 +
 include/uapi/linux/bpf.h                      |  5 ++
 kernel/bpf/syscall.c                          |  2 +-
 kernel/trace/bpf_trace.c                      |  1 +
 net/bpf/test_run.c                            | 88 +++++++++++++++++++
 tools/include/uapi/linux/bpf.h                |  5 ++
 tools/lib/bpf/bpf.c                           | 13 ++-
 tools/lib/bpf/bpf.h                           | 11 +++
 tools/lib/bpf/libbpf.map                      |  1 +
 .../bpf/prog_tests/raw_tp_test_run.c          | 73 +++++++++++++++
 .../bpf/progs/test_raw_tp_test_run.c          | 26 ++++++
 11 files changed, 226 insertions(+), 2 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/raw_tp_test_run.c
 create mode 100644 tools/testing/selftests/bpf/progs/test_raw_tp_test_run.c

--
2.24.1

[PATCH v2 bpf-next 1/3] bpf: enable BPF_PROG_TEST_RUN for raw_tracepoint

[Song Liu]

Add .test_run for raw_tracepoint. Also, introduce a new feature that runs
the target program on a specific CPU. This is achieved by a new flag in
bpf_attr.test, cpu_plus. For compatibility, cpu_plus == 0 means run the
program on current cpu, cpu_plus > 0 means run the program on cpu with id
(cpu_plus - 1). This feature is needed for BPF programs that handle
perf_event and other percpu resources, as the program can access these
resource locally.

Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Song Liu <songliubraving@fb.com>
---
 include/linux/bpf.h            |  3 ++
 include/uapi/linux/bpf.h       |  5 ++
 kernel/bpf/syscall.c           |  2 +-
 kernel/trace/bpf_trace.c       |  1 +
 net/bpf/test_run.c             | 88 ++++++++++++++++++++++++++++++++++
 tools/include/uapi/linux/bpf.h |  5 ++
 6 files changed, 103 insertions(+), 1 deletion(-)

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index d7c5a6ed87e30..23758c282eb4b 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1376,6 +1376,9 @@ int bpf_prog_test_run_tracing(struct bpf_prog *prog,
 int bpf_prog_test_run_flow_dissector(struct bpf_prog *prog,
 				     const union bpf_attr *kattr,
 				     union bpf_attr __user *uattr);
+int bpf_prog_test_run_raw_tp(struct bpf_prog *prog,
+			     const union bpf_attr *kattr,
+			     union bpf_attr __user *uattr);
 bool btf_ctx_access(int off, int size, enum bpf_access_type type,
 		    const struct bpf_prog *prog,
 		    struct bpf_insn_access_aux *info);
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index a22812561064a..89acf41913e70 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -566,6 +566,11 @@ union bpf_attr {
 						 */
 		__aligned_u64	ctx_in;
 		__aligned_u64	ctx_out;
+		__u32		cpu_plus;	/* run this program on cpu
+						 * (cpu_plus - 1).
+						 * If cpu_plus == 0, run on
+						 * current cpu.
+						 */
 	} test;
 
 	struct { /* anonymous struct used by BPF_*_GET_*_ID */
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index ec68d3a23a2b7..4664531ff92ea 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -2975,7 +2975,7 @@ static int bpf_prog_query(const union bpf_attr *attr,
 	}
 }
 
-#define BPF_PROG_TEST_RUN_LAST_FIELD test.ctx_out
+#define BPF_PROG_TEST_RUN_LAST_FIELD test.cpu_plus
 
 static int bpf_prog_test_run(const union bpf_attr *attr,
 			     union bpf_attr __user *uattr)
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index b2a5380eb1871..4553aebf53862 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -1675,6 +1675,7 @@ const struct bpf_verifier_ops raw_tracepoint_verifier_ops = {
 };
 
 const struct bpf_prog_ops raw_tracepoint_prog_ops = {
+	.test_run = bpf_prog_test_run_raw_tp,
 };
 
 const struct bpf_verifier_ops tracing_verifier_ops = {
diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
index 99eb8c6c0fbcc..b32e22f0ee16f 100644
--- a/net/bpf/test_run.c
+++ b/net/bpf/test_run.c
@@ -11,6 +11,7 @@
 #include <net/sock.h>
 #include <net/tcp.h>
 #include <linux/error-injection.h>
+#include <linux/smp.h>
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/bpf_test_run.h>
@@ -204,6 +205,9 @@ int bpf_prog_test_run_tracing(struct bpf_prog *prog,
 	int b = 2, err = -EFAULT;
 	u32 retval = 0;
 
+	if (kattr->test.cpu_plus)
+		return -EINVAL;
+
 	switch (prog->expected_attach_type) {
 	case BPF_TRACE_FENTRY:
 	case BPF_TRACE_FEXIT:
@@ -236,6 +240,84 @@ int bpf_prog_test_run_tracing(struct bpf_prog *prog,
 	return err;
 }
 
+struct bpf_raw_tp_test_run_info {
+	struct bpf_prog *prog;
+	void *ctx;
+	u32 retval;
+};
+
+static void
+__bpf_prog_test_run_raw_tp(void *data)
+{
+	struct bpf_raw_tp_test_run_info *info = data;
+
+	rcu_read_lock();
+	migrate_disable();
+	info->retval = BPF_PROG_RUN(info->prog, info->ctx);
+	migrate_enable();
+	rcu_read_unlock();
+}
+
+int bpf_prog_test_run_raw_tp(struct bpf_prog *prog,
+			     const union bpf_attr *kattr,
+			     union bpf_attr __user *uattr)
+{
+	void __user *ctx_in = u64_to_user_ptr(kattr->test.ctx_in);
+	__u32 ctx_size_in = kattr->test.ctx_size_in;
+	struct bpf_raw_tp_test_run_info info;
+	int cpu, err = 0;
+
+	/* doesn't support data_in/out, ctx_out, duration, or repeat */
+	if (kattr->test.data_in || kattr->test.data_out ||
+	    kattr->test.ctx_out || kattr->test.duration ||
+	    kattr->test.repeat)
+		return -EINVAL;
+
+	if (ctx_size_in < prog->aux->max_ctx_offset)
+		return -EINVAL;
+
+	if (ctx_size_in) {
+		info.ctx = kzalloc(ctx_size_in, GFP_USER);
+		if (!info.ctx)
+			return -ENOMEM;
+		if (copy_from_user(info.ctx, ctx_in, ctx_size_in)) {
+			err = -EFAULT;
+			goto out;
+		}
+	} else {
+		info.ctx = NULL;
+	}
+
+	info.prog = prog;
+	cpu = kattr->test.cpu_plus - 1;
+
+	if (!kattr->test.cpu_plus || cpu == smp_processor_id()) {
+		__bpf_prog_test_run_raw_tp(&info);
+	} else {
+		/* smp_call_function_single() also checks cpu_online()
+		 * after csd_lock(). However, since cpu_plus is from user
+		 * space, let's do an extra quick check to filter out
+		 * invalid value before smp_call_function_single().
+		 */
+		if (!cpu_online(cpu)) {
+			err = -ENXIO;
+			goto out;
+		}
+
+		err = smp_call_function_single(cpu, __bpf_prog_test_run_raw_tp,
+					       &info, 1);
+		if (err)
+			goto out;
+	}
+
+	if (copy_to_user(&uattr->test.retval, &info.retval, sizeof(u32)))
+		err = -EFAULT;
+
+out:
+	kfree(info.ctx);
+	return err;
+}
+
 static void *bpf_ctx_init(const union bpf_attr *kattr, u32 max_size)
 {
 	void __user *data_in = u64_to_user_ptr(kattr->test.ctx_in);
@@ -410,6 +492,9 @@ int bpf_prog_test_run_skb(struct bpf_prog *prog, const union bpf_attr *kattr,
 	void *data;
 	int ret;
 
+	if (kattr->test.cpu_plus)
+		return -EINVAL;
+
 	data = bpf_test_init(kattr, size, NET_SKB_PAD + NET_IP_ALIGN,
 			     SKB_DATA_ALIGN(sizeof(struct skb_shared_info)));
 	if (IS_ERR(data))
@@ -607,6 +692,9 @@ int bpf_prog_test_run_flow_dissector(struct bpf_prog *prog,
 	if (prog->type != BPF_PROG_TYPE_FLOW_DISSECTOR)
 		return -EINVAL;
 
+	if (kattr->test.cpu_plus)
+		return -EINVAL;
+
 	if (size < ETH_HLEN)
 		return -EINVAL;
 
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index a22812561064a..89acf41913e70 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -566,6 +566,11 @@ union bpf_attr {
 						 */
 		__aligned_u64	ctx_in;
 		__aligned_u64	ctx_out;
+		__u32		cpu_plus;	/* run this program on cpu
+						 * (cpu_plus - 1).
+						 * If cpu_plus == 0, run on
+						 * current cpu.
+						 */
 	} test;
 
 	struct { /* anonymous struct used by BPF_*_GET_*_ID */
-- 
2.24.1

[PATCH v2 bpf-next 2/3] libbpf: introduce bpf_prog_test_run_xattr_opts

[Song Liu]

This API supports new field cpu_plus in bpf_attr.test.

Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Song Liu <songliubraving@fb.com>
---
 tools/lib/bpf/bpf.c      | 13 ++++++++++++-
 tools/lib/bpf/bpf.h      | 11 +++++++++++
 tools/lib/bpf/libbpf.map |  1 +
 3 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index 2baa1308737c8..3228dd60fa32f 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -684,7 +684,8 @@ int bpf_prog_test_run(int prog_fd, int repeat, void *data, __u32 size,
 	return ret;
 }
 
-int bpf_prog_test_run_xattr(struct bpf_prog_test_run_attr *test_attr)
+int bpf_prog_test_run_xattr_opts(struct bpf_prog_test_run_attr *test_attr,
+				 const struct bpf_prog_test_run_opts *opts)
 {
 	union bpf_attr attr;
 	int ret;
@@ -693,6 +694,11 @@ int bpf_prog_test_run_xattr(struct bpf_prog_test_run_attr *test_attr)
 		return -EINVAL;
 
 	memset(&attr, 0, sizeof(attr));
+	if (opts) {
+		if (!OPTS_VALID(opts, bpf_prog_test_run_opts))
+			return -EINVAL;
+		attr.test.cpu_plus = opts->cpu_plus;
+	}
 	attr.test.prog_fd = test_attr->prog_fd;
 	attr.test.data_in = ptr_to_u64(test_attr->data_in);
 	attr.test.data_out = ptr_to_u64(test_attr->data_out);
@@ -712,6 +718,11 @@ int bpf_prog_test_run_xattr(struct bpf_prog_test_run_attr *test_attr)
 	return ret;
 }
 
+int bpf_prog_test_run_xattr(struct bpf_prog_test_run_attr *test_attr)
+{
+	return bpf_prog_test_run_xattr_opts(test_attr, NULL);
+}
+
 static int bpf_obj_get_next_id(__u32 start_id, __u32 *next_id, int cmd)
 {
 	union bpf_attr attr;
diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
index 8c1ac4b42f908..61318f47c8e1b 100644
--- a/tools/lib/bpf/bpf.h
+++ b/tools/lib/bpf/bpf.h
@@ -251,6 +251,17 @@ struct bpf_prog_bind_opts {
 
 LIBBPF_API int bpf_prog_bind_map(int prog_fd, int map_fd,
 				 const struct bpf_prog_bind_opts *opts);
+
+struct bpf_prog_test_run_opts {
+	size_t sz; /* size of this struct for forward/backward compatibility */
+	__u32 cpu_plus;
+};
+#define bpf_prog_test_run_opts__last_field cpu_plus
+
+LIBBPF_API
+int bpf_prog_test_run_xattr_opts(struct bpf_prog_test_run_attr *test_attr,
+				 const struct bpf_prog_test_run_opts *opts);
+
 #ifdef __cplusplus
 } /* extern "C" */
 #endif
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index 5f054dadf0829..c84a8bec57634 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -303,6 +303,7 @@ LIBBPF_0.1.0 {
 LIBBPF_0.2.0 {
 	global:
 		bpf_prog_bind_map;
+		bpf_prog_test_run_xattr_opts;
 		bpf_program__section_name;
 		perf_buffer__buffer_cnt;
 		perf_buffer__buffer_fd;
-- 
2.24.1

[PATCH v2 bpf-next 3/3] selftests/bpf: add raw_tp_test_run

[Song Liu]

This test runs test_run for raw_tracepoint program. The test covers ctx
input, retval output, and proper handling of cpu_plus field.

Signed-off-by: Song Liu <songliubraving@fb.com>
---
 .../bpf/prog_tests/raw_tp_test_run.c          | 73 +++++++++++++++++++
 .../bpf/progs/test_raw_tp_test_run.c          | 26 +++++++
 2 files changed, 99 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/raw_tp_test_run.c
 create mode 100644 tools/testing/selftests/bpf/progs/test_raw_tp_test_run.c

diff --git a/tools/testing/selftests/bpf/prog_tests/raw_tp_test_run.c b/tools/testing/selftests/bpf/prog_tests/raw_tp_test_run.c
new file mode 100644
index 0000000000000..3c6523b61afc1
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/raw_tp_test_run.c
@@ -0,0 +1,73 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2019 Facebook */
+#include <test_progs.h>
+#include "bpf/libbpf_internal.h"
+#include "test_raw_tp_test_run.skel.h"
+
+static int duration;
+
+void test_raw_tp_test_run(void)
+{
+	struct bpf_prog_test_run_attr test_attr = {};
+	__u64 args[2] = {0x1234ULL, 0x5678ULL};
+	int comm_fd = -1, err, nr_online, i;
+	int expected_retval = 0x1234 + 0x5678;
+	struct test_raw_tp_test_run *skel;
+	char buf[] = "new_name";
+	bool *online = NULL;
+
+	err = parse_cpu_mask_file("/sys/devices/system/cpu/online", &online,
+				  &nr_online);
+	if (CHECK(err, "parse_cpu_mask_file", "err %d\n", err))
+		return;
+
+	skel = test_raw_tp_test_run__open_and_load();
+	if (CHECK(!skel, "skel_open", "failed to open skeleton\n"))
+		return;
+	err = test_raw_tp_test_run__attach(skel);
+	if (CHECK(err, "skel_attach", "skeleton attach failed: %d\n", err))
+		goto cleanup;
+
+	comm_fd = open("/proc/self/comm", O_WRONLY|O_TRUNC);
+	if (CHECK(comm_fd < 0, "open /proc/self/comm", "err %d\n", errno))
+		goto cleanup;
+
+	err = write(comm_fd, buf, sizeof(buf));
+	CHECK(err < 0, "task rename", "err %d", errno);
+
+	CHECK(skel->bss->count == 0, "check_count", "didn't increase\n");
+	CHECK(skel->data->on_cpu != 0xffffffff, "check_on_cpu", "got wrong value\n");
+
+	test_attr.prog_fd = bpf_program__fd(skel->progs.rename);
+	test_attr.ctx_in = args;
+	test_attr.ctx_size_in = sizeof(__u64);
+
+	err = bpf_prog_test_run_xattr(&test_attr);
+	CHECK(err == 0, "test_run", "should fail for too small ctx\n");
+
+	test_attr.ctx_size_in = sizeof(args);
+	err = bpf_prog_test_run_xattr(&test_attr);
+	CHECK(err < 0, "test_run", "err %d\n", errno);
+	CHECK(test_attr.retval != expected_retval, "check_retval",
+	      "expect 0x%x, got 0x%x\n", expected_retval, test_attr.retval);
+
+	for (i = 0; i < nr_online; i++)
+		if (online[i]) {
+			DECLARE_LIBBPF_OPTS(bpf_prog_test_run_opts, opts,
+				.cpu_plus = i + 1,
+			);
+
+			test_attr.retval = 0;
+			err = bpf_prog_test_run_xattr_opts(&test_attr, &opts);
+			CHECK(err < 0, "test_run_with_opts", "err %d\n", errno);
+			CHECK(skel->data->on_cpu != i, "check_on_cpu",
+			      "got wrong value\n");
+			CHECK(test_attr.retval != expected_retval,
+			      "check_retval", "expect 0x%x, got 0x%x\n",
+			      expected_retval, test_attr.retval);
+		}
+cleanup:
+	close(comm_fd);
+	test_raw_tp_test_run__destroy(skel);
+	free(online);
+}
diff --git a/tools/testing/selftests/bpf/progs/test_raw_tp_test_run.c b/tools/testing/selftests/bpf/progs/test_raw_tp_test_run.c
new file mode 100644
index 0000000000000..9ceb648f096ea
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_raw_tp_test_run.c
@@ -0,0 +1,26 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2020 Facebook */
+
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_endian.h>
+#include <bpf/bpf_tracing.h>
+
+__u32 count = 0;
+__u32 on_cpu = 0xffffffff;
+
+SEC("raw_tp/task_rename")
+int BPF_PROG(rename, struct task_struct *task, char *comm)
+{
+
+	count++;
+	if ((unsigned long long) task == 0x1234 &&
+	    (unsigned long long) comm == 0x5678) {
+		on_cpu = bpf_get_smp_processor_id();
+		return (int)task + (int)comm;
+	}
+
+	return 0;
+}
+
+char _license[] SEC("license") = "GPL";
-- 
2.24.1

Re: [PATCH v2 bpf-next 2/3] libbpf: introduce bpf_prog_test_run_xattr_opts

[Andrii Nakryiko]

On Wed, Sep 23, 2020 at 9:55 AM Song Liu <songliubraving@fb.com> wrote:
>
> This API supports new field cpu_plus in bpf_attr.test.
>
> Acked-by: John Fastabend <john.fastabend@gmail.com>
> Signed-off-by: Song Liu <songliubraving@fb.com>
> ---
>  tools/lib/bpf/bpf.c      | 13 ++++++++++++-
>  tools/lib/bpf/bpf.h      | 11 +++++++++++
>  tools/lib/bpf/libbpf.map |  1 +
>  3 files changed, 24 insertions(+), 1 deletion(-)
>
> diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
> index 2baa1308737c8..3228dd60fa32f 100644
> --- a/tools/lib/bpf/bpf.c
> +++ b/tools/lib/bpf/bpf.c
> @@ -684,7 +684,8 @@ int bpf_prog_test_run(int prog_fd, int repeat, void *data, __u32 size,
>         return ret;
>  }
>
> -int bpf_prog_test_run_xattr(struct bpf_prog_test_run_attr *test_attr)
> +int bpf_prog_test_run_xattr_opts(struct bpf_prog_test_run_attr *test_attr,
> +                                const struct bpf_prog_test_run_opts *opts)

opts are replacement for test_attr, not an addition to it. We chose to
use _xattr suffix for low-level APIs previously, but it's already
"taken". So I'd suggest to go with just  bpf_prog_test_run_ops and
have prog_fd as a first argument and then put all the rest of
test_run_attr into opts.

BTW, it's also probably overdue to have a higher-level
bpf_program__test_run(), which can re-use the same
bpf_prog_test_run_opts options struct. It would be more convenient to
use it with libbpf bpf_object/bpf_program APIs.

>  {
>         union bpf_attr attr;
>         int ret;
> @@ -693,6 +694,11 @@ int bpf_prog_test_run_xattr(struct bpf_prog_test_run_attr *test_attr)
>                 return -EINVAL;
>
>         memset(&attr, 0, sizeof(attr));
> +       if (opts) {

you don't need to check opts for being not NULL, OPTS_VALID handle that already.

> +               if (!OPTS_VALID(opts, bpf_prog_test_run_opts))
> +                       return -EINVAL;
> +               attr.test.cpu_plus = opts->cpu_plus;

And here you should use OPTS_GET(), please see other examples in
libbpf for proper usage.


> +       }
>         attr.test.prog_fd = test_attr->prog_fd;
>         attr.test.data_in = ptr_to_u64(test_attr->data_in);
>         attr.test.data_out = ptr_to_u64(test_attr->data_out);
> @@ -712,6 +718,11 @@ int bpf_prog_test_run_xattr(struct bpf_prog_test_run_attr *test_attr)
>         return ret;
>  }
>

[...]

Re: [PATCH v2 bpf-next 1/3] bpf: enable BPF_PROG_TEST_RUN for raw_tracepoint

[Andrii Nakryiko]

On Wed, Sep 23, 2020 at 9:54 AM Song Liu <songliubraving@fb.com> wrote:
>
> Add .test_run for raw_tracepoint. Also, introduce a new feature that runs
> the target program on a specific CPU. This is achieved by a new flag in
> bpf_attr.test, cpu_plus. For compatibility, cpu_plus == 0 means run the
> program on current cpu, cpu_plus > 0 means run the program on cpu with id
> (cpu_plus - 1). This feature is needed for BPF programs that handle
> perf_event and other percpu resources, as the program can access these
> resource locally.
>
> Acked-by: John Fastabend <john.fastabend@gmail.com>
> Signed-off-by: Song Liu <songliubraving@fb.com>
> ---
>  include/linux/bpf.h            |  3 ++
>  include/uapi/linux/bpf.h       |  5 ++
>  kernel/bpf/syscall.c           |  2 +-
>  kernel/trace/bpf_trace.c       |  1 +
>  net/bpf/test_run.c             | 88 ++++++++++++++++++++++++++++++++++
>  tools/include/uapi/linux/bpf.h |  5 ++
>  6 files changed, 103 insertions(+), 1 deletion(-)
>
> diff --git a/include/linux/bpf.h b/include/linux/bpf.h
> index d7c5a6ed87e30..23758c282eb4b 100644
> --- a/include/linux/bpf.h
> +++ b/include/linux/bpf.h
> @@ -1376,6 +1376,9 @@ int bpf_prog_test_run_tracing(struct bpf_prog *prog,
>  int bpf_prog_test_run_flow_dissector(struct bpf_prog *prog,
>                                      const union bpf_attr *kattr,
>                                      union bpf_attr __user *uattr);
> +int bpf_prog_test_run_raw_tp(struct bpf_prog *prog,
> +                            const union bpf_attr *kattr,
> +                            union bpf_attr __user *uattr);
>  bool btf_ctx_access(int off, int size, enum bpf_access_type type,
>                     const struct bpf_prog *prog,
>                     struct bpf_insn_access_aux *info);
> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> index a22812561064a..89acf41913e70 100644
> --- a/include/uapi/linux/bpf.h
> +++ b/include/uapi/linux/bpf.h
> @@ -566,6 +566,11 @@ union bpf_attr {
>                                                  */
>                 __aligned_u64   ctx_in;
>                 __aligned_u64   ctx_out;
> +               __u32           cpu_plus;       /* run this program on cpu
> +                                                * (cpu_plus - 1).
> +                                                * If cpu_plus == 0, run on
> +                                                * current cpu.
> +                                                */

the "_plus" part of the name is so confusing, just as off-by-one
semantics.. Why not do what we do with BPF_PROG_ATTACH? I.e., we have
flags field, and if the specific bit is set then we use extra field's
value. In this case, you'd have:

__u32 flags;
__u32 cpu; /* naturally 0-based */

cpu indexing will be natural without any offsets, and you'll have
something like BPF_PROG_TEST_CPU flag, that needs to be specified.
This will work well with backward/forward compatibility. If you need a
special "current CPU" mode, you can achieve that by not specifying
BPF_PROG_TEST_CPU flag, or we can designate (__u32)-1 as a special
"current CPU" value.

WDYT?


>         } test;
>
>         struct { /* anonymous struct used by BPF_*_GET_*_ID */
> diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
> index ec68d3a23a2b7..4664531ff92ea 100644
> --- a/kernel/bpf/syscall.c
> +++ b/kernel/bpf/syscall.c
> @@ -2975,7 +2975,7 @@ static int bpf_prog_query(const union bpf_attr *attr,
>         }
>  }
>
> -#define BPF_PROG_TEST_RUN_LAST_FIELD test.ctx_out
> +#define BPF_PROG_TEST_RUN_LAST_FIELD test.cpu_plus
>

[...]

Re: [PATCH v2 bpf-next 3/3] selftests/bpf: add raw_tp_test_run

[Andrii Nakryiko]

On Wed, Sep 23, 2020 at 9:55 AM Song Liu <songliubraving@fb.com> wrote:
>
> This test runs test_run for raw_tracepoint program. The test covers ctx
> input, retval output, and proper handling of cpu_plus field.
>
> Signed-off-by: Song Liu <songliubraving@fb.com>
> ---
>  .../bpf/prog_tests/raw_tp_test_run.c          | 73 +++++++++++++++++++
>  .../bpf/progs/test_raw_tp_test_run.c          | 26 +++++++
>  2 files changed, 99 insertions(+)
>  create mode 100644 tools/testing/selftests/bpf/prog_tests/raw_tp_test_run.c
>  create mode 100644 tools/testing/selftests/bpf/progs/test_raw_tp_test_run.c
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/raw_tp_test_run.c b/tools/testing/selftests/bpf/prog_tests/raw_tp_test_run.c
> new file mode 100644
> index 0000000000000..3c6523b61afc1
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/prog_tests/raw_tp_test_run.c
> @@ -0,0 +1,73 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/* Copyright (c) 2019 Facebook */
> +#include <test_progs.h>
> +#include "bpf/libbpf_internal.h"
> +#include "test_raw_tp_test_run.skel.h"
> +
> +static int duration;
> +
> +void test_raw_tp_test_run(void)
> +{
> +       struct bpf_prog_test_run_attr test_attr = {};
> +       __u64 args[2] = {0x1234ULL, 0x5678ULL};
> +       int comm_fd = -1, err, nr_online, i;
> +       int expected_retval = 0x1234 + 0x5678;
> +       struct test_raw_tp_test_run *skel;
> +       char buf[] = "new_name";
> +       bool *online = NULL;
> +
> +       err = parse_cpu_mask_file("/sys/devices/system/cpu/online", &online,
> +                                 &nr_online);
> +       if (CHECK(err, "parse_cpu_mask_file", "err %d\n", err))
> +               return;
> +
> +       skel = test_raw_tp_test_run__open_and_load();
> +       if (CHECK(!skel, "skel_open", "failed to open skeleton\n"))
> +               return;

leaking memory here

> +       err = test_raw_tp_test_run__attach(skel);
> +       if (CHECK(err, "skel_attach", "skeleton attach failed: %d\n", err))
> +               goto cleanup;
> +
> +       comm_fd = open("/proc/self/comm", O_WRONLY|O_TRUNC);
> +       if (CHECK(comm_fd < 0, "open /proc/self/comm", "err %d\n", errno))
> +               goto cleanup;
> +

[...]

> +SEC("raw_tp/task_rename")
> +int BPF_PROG(rename, struct task_struct *task, char *comm)
> +{
> +
> +       count++;
> +       if ((unsigned long long) task == 0x1234 &&
> +           (unsigned long long) comm == 0x5678) {

you can use shorter __u64?

> +               on_cpu = bpf_get_smp_processor_id();
> +               return (int)task + (int)comm;
> +       }
> +
> +       return 0;
> +}
> +
> +char _license[] SEC("license") = "GPL";
> --
> 2.24.1
>

Re: [PATCH v2 bpf-next 3/3] selftests/bpf: add raw_tp_test_run

[Song Liu]

> On Sep 23, 2020, at 12:40 PM, Andrii Nakryiko <andrii.nakryiko@gmail.com> wrote:
> 
> On Wed, Sep 23, 2020 at 9:55 AM Song Liu <songliubraving@fb.com> wrote:
>> 
>> This test runs test_run for raw_tracepoint program. The test covers ctx
>> input, retval output, and proper handling of cpu_plus field.
>> 
>> Signed-off-by: Song Liu <songliubraving@fb.com>
>> ---
>> .../bpf/prog_tests/raw_tp_test_run.c          | 73 +++++++++++++++++++
>> .../bpf/progs/test_raw_tp_test_run.c          | 26 +++++++
>> 2 files changed, 99 insertions(+)
>> create mode 100644 tools/testing/selftests/bpf/prog_tests/raw_tp_test_run.c
>> create mode 100644 tools/testing/selftests/bpf/progs/test_raw_tp_test_run.c
>> 
>> diff --git a/tools/testing/selftests/bpf/prog_tests/raw_tp_test_run.c b/tools/testing/selftests/bpf/prog_tests/raw_tp_test_run.c
>> new file mode 100644
>> index 0000000000000..3c6523b61afc1
>> --- /dev/null
>> +++ b/tools/testing/selftests/bpf/prog_tests/raw_tp_test_run.c
>> @@ -0,0 +1,73 @@
>> +// SPDX-License-Identifier: GPL-2.0-only
>> +/* Copyright (c) 2019 Facebook */
>> +#include <test_progs.h>
>> +#include "bpf/libbpf_internal.h"
>> +#include "test_raw_tp_test_run.skel.h"
>> +
>> +static int duration;
>> +
>> +void test_raw_tp_test_run(void)
>> +{
>> +       struct bpf_prog_test_run_attr test_attr = {};
>> +       __u64 args[2] = {0x1234ULL, 0x5678ULL};
>> +       int comm_fd = -1, err, nr_online, i;
>> +       int expected_retval = 0x1234 + 0x5678;
>> +       struct test_raw_tp_test_run *skel;
>> +       char buf[] = "new_name";
>> +       bool *online = NULL;
>> +
>> +       err = parse_cpu_mask_file("/sys/devices/system/cpu/online", &online,
>> +                                 &nr_online);
>> +       if (CHECK(err, "parse_cpu_mask_file", "err %d\n", err))
>> +               return;
>> +
>> +       skel = test_raw_tp_test_run__open_and_load();
>> +       if (CHECK(!skel, "skel_open", "failed to open skeleton\n"))
>> +               return;
> 
> leaking memory here

Good catch! Fixing it in the next version. 

> 
>> +       err = test_raw_tp_test_run__attach(skel);
>> +       if (CHECK(err, "skel_attach", "skeleton attach failed: %d\n", err))
>> +               goto cleanup;
>> +
>> +       comm_fd = open("/proc/self/comm", O_WRONLY|O_TRUNC);
>> +       if (CHECK(comm_fd < 0, "open /proc/self/comm", "err %d\n", errno))
>> +               goto cleanup;
>> +
> 
> [...]
> 
>> +SEC("raw_tp/task_rename")
>> +int BPF_PROG(rename, struct task_struct *task, char *comm)
>> +{
>> +
>> +       count++;
>> +       if ((unsigned long long) task == 0x1234 &&
>> +           (unsigned long long) comm == 0x5678) {
> 
> you can use shorter __u64?

Sure. 

Re: [PATCH v2 bpf-next 1/3] bpf: enable BPF_PROG_TEST_RUN for raw_tracepoint

[Song Liu]

> On Sep 23, 2020, at 12:36 PM, Andrii Nakryiko <andrii.nakryiko@gmail.com> wrote:
> 
> On Wed, Sep 23, 2020 at 9:54 AM Song Liu <songliubraving@fb.com> wrote:
>> 
>> Add .test_run for raw_tracepoint. Also, introduce a new feature that runs
>> the target program on a specific CPU. This is achieved by a new flag in
>> bpf_attr.test, cpu_plus. For compatibility, cpu_plus == 0 means run the
>> program on current cpu, cpu_plus > 0 means run the program on cpu with id
>> (cpu_plus - 1). This feature is needed for BPF programs that handle
>> perf_event and other percpu resources, as the program can access these
>> resource locally.
>> 
>> Acked-by: John Fastabend <john.fastabend@gmail.com>
>> Signed-off-by: Song Liu <songliubraving@fb.com>
>> ---
>> include/linux/bpf.h            |  3 ++
>> include/uapi/linux/bpf.h       |  5 ++
>> kernel/bpf/syscall.c           |  2 +-
>> kernel/trace/bpf_trace.c       |  1 +
>> net/bpf/test_run.c             | 88 ++++++++++++++++++++++++++++++++++
>> tools/include/uapi/linux/bpf.h |  5 ++
>> 6 files changed, 103 insertions(+), 1 deletion(-)
>> 
>> diff --git a/include/linux/bpf.h b/include/linux/bpf.h
>> index d7c5a6ed87e30..23758c282eb4b 100644
>> --- a/include/linux/bpf.h
>> +++ b/include/linux/bpf.h
>> @@ -1376,6 +1376,9 @@ int bpf_prog_test_run_tracing(struct bpf_prog *prog,
>> int bpf_prog_test_run_flow_dissector(struct bpf_prog *prog,
>>                                     const union bpf_attr *kattr,
>>                                     union bpf_attr __user *uattr);
>> +int bpf_prog_test_run_raw_tp(struct bpf_prog *prog,
>> +                            const union bpf_attr *kattr,
>> +                            union bpf_attr __user *uattr);
>> bool btf_ctx_access(int off, int size, enum bpf_access_type type,
>>                    const struct bpf_prog *prog,
>>                    struct bpf_insn_access_aux *info);
>> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
>> index a22812561064a..89acf41913e70 100644
>> --- a/include/uapi/linux/bpf.h
>> +++ b/include/uapi/linux/bpf.h
>> @@ -566,6 +566,11 @@ union bpf_attr {
>>                                                 */
>>                __aligned_u64   ctx_in;
>>                __aligned_u64   ctx_out;
>> +               __u32           cpu_plus;       /* run this program on cpu
>> +                                                * (cpu_plus - 1).
>> +                                                * If cpu_plus == 0, run on
>> +                                                * current cpu.
>> +                                                */
> 
> the "_plus" part of the name is so confusing, just as off-by-one
> semantics.. Why not do what we do with BPF_PROG_ATTACH? I.e., we have
> flags field, and if the specific bit is set then we use extra field's
> value. In this case, you'd have:
> 
> __u32 flags;
> __u32 cpu; /* naturally 0-based */
> 
> cpu indexing will be natural without any offsets, and you'll have
> something like BPF_PROG_TEST_CPU flag, that needs to be specified.
> This will work well with backward/forward compatibility. If you need a
> special "current CPU" mode, you can achieve that by not specifying
> BPF_PROG_TEST_CPU flag, or we can designate (__u32)-1 as a special
> "current CPU" value.
> 
> WDYT?

Yes, we can add a flag here. If there was already a flags field in
bpf_attr.test, I would have gone that way in the first place. 

Thanks,
Song

Re: [PATCH v2 bpf-next 2/3] libbpf: introduce bpf_prog_test_run_xattr_opts

[Song Liu]

> On Sep 23, 2020, at 12:31 PM, Andrii Nakryiko <andrii.nakryiko@gmail.com> wrote:
> 
> On Wed, Sep 23, 2020 at 9:55 AM Song Liu <songliubraving@fb.com> wrote:
>> 
>> This API supports new field cpu_plus in bpf_attr.test.
>> 
>> Acked-by: John Fastabend <john.fastabend@gmail.com>
>> Signed-off-by: Song Liu <songliubraving@fb.com>
>> ---
>> tools/lib/bpf/bpf.c      | 13 ++++++++++++-
>> tools/lib/bpf/bpf.h      | 11 +++++++++++
>> tools/lib/bpf/libbpf.map |  1 +
>> 3 files changed, 24 insertions(+), 1 deletion(-)
>> 
>> diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
>> index 2baa1308737c8..3228dd60fa32f 100644
>> --- a/tools/lib/bpf/bpf.c
>> +++ b/tools/lib/bpf/bpf.c
>> @@ -684,7 +684,8 @@ int bpf_prog_test_run(int prog_fd, int repeat, void *data, __u32 size,
>>        return ret;
>> }
>> 
>> -int bpf_prog_test_run_xattr(struct bpf_prog_test_run_attr *test_attr)
>> +int bpf_prog_test_run_xattr_opts(struct bpf_prog_test_run_attr *test_attr,
>> +                                const struct bpf_prog_test_run_opts *opts)
> 
> opts are replacement for test_attr, not an addition to it. We chose to
> use _xattr suffix for low-level APIs previously, but it's already
> "taken". So I'd suggest to go with just  bpf_prog_test_run_ops and
> have prog_fd as a first argument and then put all the rest of
> test_run_attr into opts.

Sounds good. I will update it this way. 

[...]

Re: [PATCH v2 bpf-next 2/3] libbpf: introduce bpf_prog_test_run_xattr_opts

[Song Liu]

> On Sep 23, 2020, at 12:31 PM, Andrii Nakryiko <andrii.nakryiko@gmail.com> wrote:
> 
> On Wed, Sep 23, 2020 at 9:55 AM Song Liu <songliubraving@fb.com> wrote:
>> 
>> This API supports new field cpu_plus in bpf_attr.test.
>> 
>> Acked-by: John Fastabend <john.fastabend@gmail.com>
>> Signed-off-by: Song Liu <songliubraving@fb.com>
>> ---
>> tools/lib/bpf/bpf.c      | 13 ++++++++++++-
>> tools/lib/bpf/bpf.h      | 11 +++++++++++
>> tools/lib/bpf/libbpf.map |  1 +
>> 3 files changed, 24 insertions(+), 1 deletion(-)
>> 
>> diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
>> index 2baa1308737c8..3228dd60fa32f 100644
>> --- a/tools/lib/bpf/bpf.c
>> +++ b/tools/lib/bpf/bpf.c
>> @@ -684,7 +684,8 @@ int bpf_prog_test_run(int prog_fd, int repeat, void *data, __u32 size,
>>        return ret;
>> }
>> 
>> -int bpf_prog_test_run_xattr(struct bpf_prog_test_run_attr *test_attr)
>> +int bpf_prog_test_run_xattr_opts(struct bpf_prog_test_run_attr *test_attr,
>> +                                const struct bpf_prog_test_run_opts *opts)
> 
> opts are replacement for test_attr, not an addition to it. We chose to
> use _xattr suffix for low-level APIs previously, but it's already
> "taken". So I'd suggest to go with just  bpf_prog_test_run_ops and
> have prog_fd as a first argument and then put all the rest of
> test_run_attr into opts.

One question on this: from the code, most (if not all) of these xxx_opts
are used as input only. For example:

LIBBPF_API int bpf_prog_bind_map(int prog_fd, int map_fd,
                                 const struct bpf_prog_bind_opts *opts);

However, bpf_prog_test_run_attr contains both input and output. Do you
have any concern we use bpf_prog_test_run_opts for both input and output?

Thanks,
Song


> BTW, it's also probably overdue to have a higher-level
> bpf_program__test_run(), which can re-use the same
> bpf_prog_test_run_opts options struct. It would be more convenient to
> use it with libbpf bpf_object/bpf_program APIs.
> 
>> {
>>        union bpf_attr attr;
>>        int ret;
>> @@ -693,6 +694,11 @@ int bpf_prog_test_run_xattr(struct bpf_prog_test_run_attr *test_attr)
>>                return -EINVAL;
>> 
>>        memset(&attr, 0, sizeof(attr));
>> +       if (opts) {
> 
> you don't need to check opts for being not NULL, OPTS_VALID handle that already.
> 
>> +               if (!OPTS_VALID(opts, bpf_prog_test_run_opts))
>> +                       return -EINVAL;
>> +               attr.test.cpu_plus = opts->cpu_plus;
> 
> And here you should use OPTS_GET(), please see other examples in
> libbpf for proper usage.
> 
> 
>> +       }
>>        attr.test.prog_fd = test_attr->prog_fd;
>>        attr.test.data_in = ptr_to_u64(test_attr->data_in);
>>        attr.test.data_out = ptr_to_u64(test_attr->data_out);
>> @@ -712,6 +718,11 @@ int bpf_prog_test_run_xattr(struct bpf_prog_test_run_attr *test_attr)
>>        return ret;
>> }
>> 
> 
> [...]

Re: [PATCH v2 bpf-next 2/3] libbpf: introduce bpf_prog_test_run_xattr_opts

[Andrii Nakryiko]

On Wed, Sep 23, 2020 at 4:54 PM Song Liu <songliubraving@fb.com> wrote:
>
>
>
> > On Sep 23, 2020, at 12:31 PM, Andrii Nakryiko <andrii.nakryiko@gmail.com> wrote:
> >
> > On Wed, Sep 23, 2020 at 9:55 AM Song Liu <songliubraving@fb.com> wrote:
> >>
> >> This API supports new field cpu_plus in bpf_attr.test.
> >>
> >> Acked-by: John Fastabend <john.fastabend@gmail.com>
> >> Signed-off-by: Song Liu <songliubraving@fb.com>
> >> ---
> >> tools/lib/bpf/bpf.c      | 13 ++++++++++++-
> >> tools/lib/bpf/bpf.h      | 11 +++++++++++
> >> tools/lib/bpf/libbpf.map |  1 +
> >> 3 files changed, 24 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
> >> index 2baa1308737c8..3228dd60fa32f 100644
> >> --- a/tools/lib/bpf/bpf.c
> >> +++ b/tools/lib/bpf/bpf.c
> >> @@ -684,7 +684,8 @@ int bpf_prog_test_run(int prog_fd, int repeat, void *data, __u32 size,
> >>        return ret;
> >> }
> >>
> >> -int bpf_prog_test_run_xattr(struct bpf_prog_test_run_attr *test_attr)
> >> +int bpf_prog_test_run_xattr_opts(struct bpf_prog_test_run_attr *test_attr,
> >> +                                const struct bpf_prog_test_run_opts *opts)
> >
> > opts are replacement for test_attr, not an addition to it. We chose to
> > use _xattr suffix for low-level APIs previously, but it's already
> > "taken". So I'd suggest to go with just  bpf_prog_test_run_ops and
> > have prog_fd as a first argument and then put all the rest of
> > test_run_attr into opts.
>
> One question on this: from the code, most (if not all) of these xxx_opts
> are used as input only. For example:
>
> LIBBPF_API int bpf_prog_bind_map(int prog_fd, int map_fd,
>                                  const struct bpf_prog_bind_opts *opts);
>
> However, bpf_prog_test_run_attr contains both input and output. Do you
> have any concern we use bpf_prog_test_run_opts for both input and output?
>

I think it should be ok. opts are about passing optional things in a
way that would be backward/forward compatible. Whether it's input
only, output only, or input/output is secondary. We haven't had a need
for output params yet, so this will be the first, but I think it fits
here just fine. Just document it in the struct definition clearly and
that's it. As for the mechanics, we might want to do OPTS_SET() macro,
that will set some fields only if the user provided enough memory to
fir that output parameter. That should work here pretty cleanly,
right?

> Thanks,
> Song
>
>
> > BTW, it's also probably overdue to have a higher-level
> > bpf_program__test_run(), which can re-use the same
> > bpf_prog_test_run_opts options struct. It would be more convenient to
> > use it with libbpf bpf_object/bpf_program APIs.
> >
> >> {
> >>        union bpf_attr attr;
> >>        int ret;
> >> @@ -693,6 +694,11 @@ int bpf_prog_test_run_xattr(struct bpf_prog_test_run_attr *test_attr)
> >>                return -EINVAL;
> >>
> >>        memset(&attr, 0, sizeof(attr));
> >> +       if (opts) {
> >
> > you don't need to check opts for being not NULL, OPTS_VALID handle that already.
> >
> >> +               if (!OPTS_VALID(opts, bpf_prog_test_run_opts))
> >> +                       return -EINVAL;
> >> +               attr.test.cpu_plus = opts->cpu_plus;
> >
> > And here you should use OPTS_GET(), please see other examples in
> > libbpf for proper usage.
> >
> >
> >> +       }
> >>        attr.test.prog_fd = test_attr->prog_fd;
> >>        attr.test.data_in = ptr_to_u64(test_attr->data_in);
> >>        attr.test.data_out = ptr_to_u64(test_attr->data_out);
> >> @@ -712,6 +718,11 @@ int bpf_prog_test_run_xattr(struct bpf_prog_test_run_attr *test_attr)
> >>        return ret;
> >> }
> >>
> >
> > [...]
>

Re: [PATCH v2 bpf-next 2/3] libbpf: introduce bpf_prog_test_run_xattr_opts

[Song Liu]

> On Sep 23, 2020, at 6:11 PM, Andrii Nakryiko <andrii.nakryiko@gmail.com> wrote:
> 
> On Wed, Sep 23, 2020 at 4:54 PM Song Liu <songliubraving@fb.com> wrote:
>> 
>> 
>> 
>>> On Sep 23, 2020, at 12:31 PM, Andrii Nakryiko <andrii.nakryiko@gmail.com> wrote:
>>> 
>>> On Wed, Sep 23, 2020 at 9:55 AM Song Liu <songliubraving@fb.com> wrote:
>>>> 
>>>> This API supports new field cpu_plus in bpf_attr.test.
>>>> 
>>>> Acked-by: John Fastabend <john.fastabend@gmail.com>
>>>> Signed-off-by: Song Liu <songliubraving@fb.com>
>>>> ---
>>>> tools/lib/bpf/bpf.c      | 13 ++++++++++++-
>>>> tools/lib/bpf/bpf.h      | 11 +++++++++++
>>>> tools/lib/bpf/libbpf.map |  1 +
>>>> 3 files changed, 24 insertions(+), 1 deletion(-)
>>>> 
>>>> diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
>>>> index 2baa1308737c8..3228dd60fa32f 100644
>>>> --- a/tools/lib/bpf/bpf.c
>>>> +++ b/tools/lib/bpf/bpf.c
>>>> @@ -684,7 +684,8 @@ int bpf_prog_test_run(int prog_fd, int repeat, void *data, __u32 size,
>>>>       return ret;
>>>> }
>>>> 
>>>> -int bpf_prog_test_run_xattr(struct bpf_prog_test_run_attr *test_attr)
>>>> +int bpf_prog_test_run_xattr_opts(struct bpf_prog_test_run_attr *test_attr,
>>>> +                                const struct bpf_prog_test_run_opts *opts)
>>> 
>>> opts are replacement for test_attr, not an addition to it. We chose to
>>> use _xattr suffix for low-level APIs previously, but it's already
>>> "taken". So I'd suggest to go with just  bpf_prog_test_run_ops and
>>> have prog_fd as a first argument and then put all the rest of
>>> test_run_attr into opts.
>> 
>> One question on this: from the code, most (if not all) of these xxx_opts
>> are used as input only. For example:
>> 
>> LIBBPF_API int bpf_prog_bind_map(int prog_fd, int map_fd,
>>                                 const struct bpf_prog_bind_opts *opts);
>> 
>> However, bpf_prog_test_run_attr contains both input and output. Do you
>> have any concern we use bpf_prog_test_run_opts for both input and output?
>> 
> 
> I think it should be ok. opts are about passing optional things in a
> way that would be backward/forward compatible. Whether it's input
> only, output only, or input/output is secondary. We haven't had a need
> for output params yet, so this will be the first, but I think it fits
> here just fine. Just document it in the struct definition clearly and
> that's it. As for the mechanics, we might want to do OPTS_SET() macro,
> that will set some fields only if the user provided enough memory to
> fir that output parameter. That should work here pretty cleanly,
> right?

Yep, just sent v4 with OPTS_SET(). ;)

Thanks,
Song