selftests/bpf: Test struct_ops maps with a large number of struct_ops program.

Create and load a struct_ops map with a large number of struct_ops
programs to generate trampolines taking a size over multiple pages. The
map includes 40 programs. Their trampolines takes 6.6k+, more than 1.5
pages, on x86.

Signed-off-by: Kui-Feng Lee <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Martin KaFai Lau <[email protected]>

1 files changed, 30 insertions, 0 deletions

diff --git a/tools/testing/selftests/bpf/prog_tests/test_struct_ops_multi_pages.c b/tools/testing/selftests/bpf/prog_tests/test_struct_ops_multi_pages.c
new file mode 100644
index 000000000000..645d32b5160c
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/test_struct_ops_multi_pages.c
@@ -0,0 +1,30 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2024 Meta Platforms, Inc. and affiliates. */
+#include <test_progs.h>
+
+#include "struct_ops_multi_pages.skel.h"
+
+static void do_struct_ops_multi_pages(void)
+{
+	struct struct_ops_multi_pages *skel;
+	struct bpf_link *link;
+
+	/* The size of all trampolines of skel->maps.multi_pages should be
+	 * over 1 page (at least for x86).
+	 */
+	skel = struct_ops_multi_pages__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "struct_ops_multi_pages_open_and_load"))
+		return;
+
+	link = bpf_map__attach_struct_ops(skel->maps.multi_pages);
+	ASSERT_OK_PTR(link, "attach_multi_pages");
+
+	bpf_link__destroy(link);
+	struct_ops_multi_pages__destroy(skel);
+}
+
+void test_struct_ops_multi_pages(void)
+{
+	if (test__start_subtest("multi_pages"))
+		do_struct_ops_multi_pages();
+}