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Date: Wed, 14 Dec 2022 00:24:40 +0100
From: Toke Høiland-Jørgensen <toke@...hat.com>
To: Andrii Nakryiko <andrii@...nel.org>,
Mykola Lysenko <mykolal@...com>,
Alexei Starovoitov <ast@...nel.org>,
Daniel Borkmann <daniel@...earbox.net>,
Martin KaFai Lau <martin.lau@...ux.dev>,
Song Liu <song@...nel.org>, Yonghong Song <yhs@...com>,
John Fastabend <john.fastabend@...il.com>,
KP Singh <kpsingh@...nel.org>,
Stanislav Fomichev <sdf@...gle.com>,
Hao Luo <haoluo@...gle.com>, Jiri Olsa <jolsa@...nel.org>,
"David S. Miller" <davem@...emloft.net>,
Jakub Kicinski <kuba@...nel.org>,
Jesper Dangaard Brouer <hawk@...nel.org>
Cc: Toke Høiland-Jørgensen <toke@...hat.com>,
Shuah Khan <shuah@...nel.org>, bpf@...r.kernel.org,
netdev@...r.kernel.org
Subject: [PATCH bpf v3 2/2] selftests/bpf: Add a test for using a cpumap from an freplace-to-XDP program
This adds a simple test for inserting an XDP program into a cpumap that is
"owned" by an XDP program that was loaded as PROG_TYPE_EXT (as libxdp
does). Prior to the kernel fix this would fail because the map type
ownership would be set to PROG_TYPE_EXT instead of being resolved to
PROG_TYPE_XDP.
v3:
- Update comment to better explain the cause
- Add Yonghong's ACK
Acked-by: Yonghong Song <yhs@...com>
Signed-off-by: Toke Høiland-Jørgensen <toke@...hat.com>
---
.../selftests/bpf/prog_tests/fexit_bpf2bpf.c | 57 +++++++++++++++++++
.../selftests/bpf/progs/freplace_progmap.c | 24 ++++++++
tools/testing/selftests/bpf/testing_helpers.c | 24 +++++++-
tools/testing/selftests/bpf/testing_helpers.h | 2 +
4 files changed, 105 insertions(+), 2 deletions(-)
create mode 100644 tools/testing/selftests/bpf/progs/freplace_progmap.c
diff --git a/tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c b/tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c
index d1e32e792536..fa8e129d1a71 100644
--- a/tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c
+++ b/tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c
@@ -500,6 +500,61 @@ static void test_fentry_to_cgroup_bpf(void)
bind4_prog__destroy(skel);
}
+static void test_func_replace_progmap(void)
+{
+ struct bpf_cpumap_val value = { .qsize = 1 };
+ struct bpf_object *obj, *tgt_obj = NULL;
+ struct bpf_program *drop, *redirect;
+ struct bpf_map *cpumap;
+ int err, tgt_fd;
+ __u32 key = 0;
+
+ err = bpf_prog_test_open("freplace_progmap.bpf.o", BPF_PROG_TYPE_UNSPEC, &obj);
+ if (!ASSERT_OK(err, "prog_open"))
+ return;
+
+ err = bpf_prog_test_load("xdp_dummy.bpf.o", BPF_PROG_TYPE_UNSPEC, &tgt_obj, &tgt_fd);
+ if (!ASSERT_OK(err, "tgt_prog_load"))
+ goto out;
+
+ drop = bpf_object__find_program_by_name(obj, "xdp_drop_prog");
+ redirect = bpf_object__find_program_by_name(obj, "xdp_cpumap_prog");
+ cpumap = bpf_object__find_map_by_name(obj, "cpu_map");
+
+ if (!ASSERT_OK_PTR(drop, "drop") || !ASSERT_OK_PTR(redirect, "redirect") ||
+ !ASSERT_OK_PTR(cpumap, "cpumap"))
+ goto out;
+
+ /* Change the 'redirect' program type to be a PROG_TYPE_EXT
+ * with an XDP target
+ */
+ bpf_program__set_type(redirect, BPF_PROG_TYPE_EXT);
+ bpf_program__set_expected_attach_type(redirect, 0);
+ err = bpf_program__set_attach_target(redirect, tgt_fd, "xdp_dummy_prog");
+ if (!ASSERT_OK(err, "set_attach_target"))
+ goto out;
+
+ err = bpf_object__load(obj);
+ if (!ASSERT_OK(err, "obj_load"))
+ goto out;
+
+ /* Prior to fixing the kernel, loading the PROG_TYPE_EXT 'redirect'
+ * program above will cause the map owner type of 'cpumap' to be set to
+ * PROG_TYPE_EXT. This in turn will cause the bpf_map_update_elem()
+ * below to fail, because the program we are inserting into the map is
+ * of PROG_TYPE_XDP. After fixing the kernel, the initial ownership will
+ * be correctly resolved to the *target* of the PROG_TYPE_EXT program
+ * (i.e., PROG_TYPE_XDP) and the map update will succeed.
+ */
+ value.bpf_prog.fd = bpf_program__fd(drop);
+ err = bpf_map_update_elem(bpf_map__fd(cpumap), &key, &value, 0);
+ ASSERT_OK(err, "map_update");
+
+out:
+ bpf_object__close(tgt_obj);
+ bpf_object__close(obj);
+}
+
/* NOTE: affect other tests, must run in serial mode */
void serial_test_fexit_bpf2bpf(void)
{
@@ -525,4 +580,6 @@ void serial_test_fexit_bpf2bpf(void)
test_func_replace_global_func();
if (test__start_subtest("fentry_to_cgroup_bpf"))
test_fentry_to_cgroup_bpf();
+ if (test__start_subtest("func_replace_progmap"))
+ test_func_replace_progmap();
}
diff --git a/tools/testing/selftests/bpf/progs/freplace_progmap.c b/tools/testing/selftests/bpf/progs/freplace_progmap.c
new file mode 100644
index 000000000000..68174c3d7b37
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/freplace_progmap.c
@@ -0,0 +1,24 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+
+struct {
+ __uint(type, BPF_MAP_TYPE_CPUMAP);
+ __uint(key_size, sizeof(__u32));
+ __uint(value_size, sizeof(struct bpf_cpumap_val));
+ __uint(max_entries, 1);
+} cpu_map SEC(".maps");
+
+SEC("xdp/cpumap")
+int xdp_drop_prog(struct xdp_md *ctx)
+{
+ return XDP_DROP;
+}
+
+SEC("xdp")
+int xdp_cpumap_prog(struct xdp_md *ctx)
+{
+ return bpf_redirect_map(&cpu_map, 0, XDP_PASS);
+}
+
+char _license[] SEC("license") = "GPL";
diff --git a/tools/testing/selftests/bpf/testing_helpers.c b/tools/testing/selftests/bpf/testing_helpers.c
index 9695318e8132..2050244e6f24 100644
--- a/tools/testing/selftests/bpf/testing_helpers.c
+++ b/tools/testing/selftests/bpf/testing_helpers.c
@@ -174,8 +174,8 @@ __u32 link_info_prog_id(const struct bpf_link *link, struct bpf_link_info *info)
int extra_prog_load_log_flags = 0;
-int bpf_prog_test_load(const char *file, enum bpf_prog_type type,
- struct bpf_object **pobj, int *prog_fd)
+int bpf_prog_test_open(const char *file, enum bpf_prog_type type,
+ struct bpf_object **pobj)
{
LIBBPF_OPTS(bpf_object_open_opts, opts,
.kernel_log_level = extra_prog_load_log_flags,
@@ -201,6 +201,26 @@ int bpf_prog_test_load(const char *file, enum bpf_prog_type type,
flags = bpf_program__flags(prog) | BPF_F_TEST_RND_HI32;
bpf_program__set_flags(prog, flags);
+ *pobj = obj;
+ return 0;
+err_out:
+ bpf_object__close(obj);
+ return err;
+}
+
+int bpf_prog_test_load(const char *file, enum bpf_prog_type type,
+ struct bpf_object **pobj, int *prog_fd)
+{
+ struct bpf_program *prog;
+ struct bpf_object *obj;
+ int err;
+
+ err = bpf_prog_test_open(file, type, &obj);
+ if (err)
+ return err;
+
+ prog = bpf_object__next_program(obj, NULL);
+
err = bpf_object__load(obj);
if (err)
goto err_out;
diff --git a/tools/testing/selftests/bpf/testing_helpers.h b/tools/testing/selftests/bpf/testing_helpers.h
index 6ec00bf79cb5..977eb520d119 100644
--- a/tools/testing/selftests/bpf/testing_helpers.h
+++ b/tools/testing/selftests/bpf/testing_helpers.h
@@ -6,6 +6,8 @@
int parse_num_list(const char *s, bool **set, int *set_len);
__u32 link_info_prog_id(const struct bpf_link *link, struct bpf_link_info *info);
+int bpf_prog_test_open(const char *file, enum bpf_prog_type type,
+ struct bpf_object **pobj);
int bpf_prog_test_load(const char *file, enum bpf_prog_type type,
struct bpf_object **pobj, int *prog_fd);
int bpf_test_load_program(enum bpf_prog_type type, const struct bpf_insn *insns,
--
2.38.1
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