[v4,bpf-next,11/13] bpf: add xdp multi-buffer selftest

diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_mb.c b/tools/testing/selftests/bpf/prog_tests/xdp_mb.c
new file mode 100644
index 000000000000..4b1aca2d31e5
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/xdp_mb.c
@@ -0,0 +1,79 @@ 
+// SPDX-License-Identifier: GPL-2.0
+
+#include <unistd.h>
+#include <linux/kernel.h>
+#include <test_progs.h>
+#include <network_helpers.h>
+
+#include "test_xdp_multi_buff.skel.h"
+
+static void test_xdp_mb_check_len(void)
+{
+	int test_sizes[] = { 128, 4096, 9000 };
+	struct test_xdp_multi_buff *pkt_skel;
+	__u8 *pkt_in = NULL, *pkt_out = NULL;
+	__u32 duration = 0, retval, size;
+	int err, pkt_fd, i;
+
+	/* Load XDP program */
+	pkt_skel = test_xdp_multi_buff__open_and_load();
+	if (CHECK(!pkt_skel, "pkt_skel_load", "test_xdp_mb skeleton failed\n"))
+		goto out;
+
+	/* Allocate resources */
+	pkt_out = malloc(test_sizes[ARRAY_SIZE(test_sizes) - 1]);
+	if (CHECK(!pkt_out, "malloc", "Failed pkt_out malloc\n"))
+		goto out;
+
+	pkt_in = malloc(test_sizes[ARRAY_SIZE(test_sizes) - 1]);
+	if (CHECK(!pkt_in, "malloc", "Failed pkt_in malloc\n"))
+		goto out;
+
+	pkt_fd = bpf_program__fd(pkt_skel->progs._xdp_check_mb_len);
+	if (pkt_fd < 0)
+		goto out;
+
+	/* Run test for specific set of packets */
+	for (i = 0; i < ARRAY_SIZE(test_sizes); i++) {
+		int frags_count;
+
+		/* Run test program */
+		err = bpf_prog_test_run(pkt_fd, 1, pkt_in, test_sizes[i],
+					pkt_out, &size, &retval, &duration);
+
+		if (CHECK(err || retval != XDP_PASS || size != test_sizes[i],
+			  "test_run", "err %d errno %d retval %d size %d[%d]\n",
+			  err, errno, retval, size, test_sizes[i]))
+			goto out;
+
+		/* Verify test results */
+		frags_count = DIV_ROUND_UP(
+			test_sizes[i] - pkt_skel->data->test_result_xdp_len,
+			getpagesize());
+
+		if (CHECK(pkt_skel->data->test_result_frags_count != frags_count,
+			  "result", "frags_count = %llu != %u\n",
+			  pkt_skel->data->test_result_frags_count, frags_count))
+			goto out;
+
+		if (CHECK(pkt_skel->data->test_result_frags_len != test_sizes[i] -
+			  pkt_skel->data->test_result_xdp_len,
+			  "result", "frags_len = %llu != %llu\n",
+			  pkt_skel->data->test_result_frags_len,
+			  test_sizes[i] - pkt_skel->data->test_result_xdp_len))
+			goto out;
+	}
+out:
+	if (pkt_out)
+		free(pkt_out);
+	if (pkt_in)
+		free(pkt_in);
+
+	test_xdp_multi_buff__destroy(pkt_skel);
+}
+
+void test_xdp_mb(void)
+{
+	if (test__start_subtest("xdp_mb_check_len_frags"))
+		test_xdp_mb_check_len();
+}
diff --git a/tools/testing/selftests/bpf/progs/test_xdp_multi_buff.c b/tools/testing/selftests/bpf/progs/test_xdp_multi_buff.c
new file mode 100644
index 000000000000..b7527829a3ed
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_xdp_multi_buff.c
@@ -0,0 +1,24 @@ 
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/bpf.h>
+#include <linux/if_ether.h>
+#include <bpf/bpf_helpers.h>
+#include <stdint.h>
+
+__u64 test_result_frags_count = UINT64_MAX;
+__u64 test_result_frags_len = UINT64_MAX;
+__u64 test_result_xdp_len = UINT64_MAX;
+
+SEC("xdp_check_mb_len")
+int _xdp_check_mb_len(struct xdp_md *xdp)
+{
+	void *data_end = (void *)(long)xdp->data_end;
+	void *data = (void *)(long)xdp->data;
+
+	test_result_xdp_len = (__u64)(data_end - data);
+	test_result_frags_len = bpf_xdp_get_frags_total_size(xdp);
+	test_result_frags_count = bpf_xdp_get_frags_count(xdp);
+	return XDP_PASS;
+}
+
+char _license[] SEC("license") = "GPL";