[PATCH bpf-next v2 07/10] selftests: xsk: Add test UNALIGNED_INV_DESC_4K1_FRAME_SIZE

[Kal Conley <kal.conley@dectris.com>]

Add unaligned descriptor test for frame size of 4001. Using an odd frame
size ensures that the end of the UMEM is not near a page boundary. This
allows testing descriptors that staddle the end of the UMEM but not a
page.

This test used to fail without the previous commit ("xsk: Add check for
unaligned descriptors that overrun UMEM").

Signed-off-by: Kal Conley <kal.conley@dectris.com>
---
 tools/testing/selftests/bpf/xskxceiver.c | 25 ++++++++++++++++++++++++
 tools/testing/selftests/bpf/xskxceiver.h |  1 +
 2 files changed, 26 insertions(+)

diff --git a/tools/testing/selftests/bpf/xskxceiver.c b/tools/testing/selftests/bpf/xskxceiver.c
index 1a4bdd5aa78c..9b9efd0e0a4c 100644
--- a/tools/testing/selftests/bpf/xskxceiver.c
+++ b/tools/testing/selftests/bpf/xskxceiver.c
@@ -69,6 +69,7 @@
  */
 
 #define _GNU_SOURCE
+#include <assert.h>
 #include <fcntl.h>
 #include <errno.h>
 #include <getopt.h>
@@ -1876,6 +1877,30 @@ static void run_pkt_test(struct test_spec *test, enum test_mode mode, enum test_
 		test->ifobj_rx->umem->unaligned_mode = true;
 		testapp_invalid_desc(test);
 		break;
+	case TEST_TYPE_UNALIGNED_INV_DESC_4K1_FRAME:
+		if (!hugepages_present(test->ifobj_tx)) {
+			ksft_test_result_skip("No 2M huge pages present.\n");
+			return;
+		}
+		test_spec_set_name(test, "UNALIGNED_INV_DESC_4K1_FRAME_SIZE");
+		/* Odd frame size so the UMEM doesn't end near a page boundary. */
+		test->ifobj_tx->umem->frame_size = 4001;
+		test->ifobj_rx->umem->frame_size = 4001;
+		test->ifobj_tx->umem->unaligned_mode = true;
+		test->ifobj_rx->umem->unaligned_mode = true;
+		/* This test exists to test descriptors that staddle the end of
+		 * the UMEM but not a page.
+		 */
+		{
+			u64 umem_size = test->ifobj_tx->umem->num_frames *
+					test->ifobj_tx->umem->frame_size;
+			u64 page_size = sysconf(_SC_PAGESIZE);
+
+			assert(umem_size % page_size > PKT_SIZE);
+			assert(umem_size % page_size < page_size - PKT_SIZE);
+		}
+		testapp_invalid_desc(test);
+		break;
 	case TEST_TYPE_UNALIGNED:
 		if (!testapp_unaligned(test))
 			return;
diff --git a/tools/testing/selftests/bpf/xskxceiver.h b/tools/testing/selftests/bpf/xskxceiver.h
index cc24ab72f3ff..919327807a4e 100644
--- a/tools/testing/selftests/bpf/xskxceiver.h
+++ b/tools/testing/selftests/bpf/xskxceiver.h
@@ -78,6 +78,7 @@ enum test_type {
 	TEST_TYPE_ALIGNED_INV_DESC,
 	TEST_TYPE_ALIGNED_INV_DESC_2K_FRAME,
 	TEST_TYPE_UNALIGNED_INV_DESC,
+	TEST_TYPE_UNALIGNED_INV_DESC_4K1_FRAME,
 	TEST_TYPE_HEADROOM,
 	TEST_TYPE_TEARDOWN,
 	TEST_TYPE_BIDI,
-- 
2.39.2