[PATCH v3 10/10] tools/testing/selftests: extend mremap_test to test multi-VMA mremap

[Lorenzo Stoakes <lorenzo.stoakes@oracle.com>]

Now that we have added the ability to move multiple VMAs at once, assert
that this functions correctly, both overwriting VMAs and moving backwards
and forwards with merge and VMA invalidation.

Additionally assert that page tables are correctly propagated by setting
random data and reading it back.

Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
---
 tools/testing/selftests/mm/mremap_test.c | 146 ++++++++++++++++++++++-
 1 file changed, 145 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/mm/mremap_test.c b/tools/testing/selftests/mm/mremap_test.c
index bb84476a177f..0a49be11e614 100644
--- a/tools/testing/selftests/mm/mremap_test.c
+++ b/tools/testing/selftests/mm/mremap_test.c
@@ -380,6 +380,149 @@ static void mremap_move_within_range(unsigned int pattern_seed, char *rand_addr)
 		ksft_test_result_fail("%s\n", test_name);
 }
 
+static bool is_multiple_vma_range_ok(unsigned int pattern_seed,
+				     char *ptr, unsigned long page_size)
+{
+	int i;
+
+	srand(pattern_seed);
+	for (i = 0; i <= 10; i += 2) {
+		int j;
+		char *buf = &ptr[i * page_size];
+		size_t size = i == 4 ? 2 * page_size : page_size;
+
+		for (j = 0; j < size; j++) {
+			char chr = rand();
+
+			if (chr != buf[j]) {
+				ksft_print_msg("page %d offset %d corrupted, expected %d got %d\n",
+					       i, j, chr, buf[j]);
+				return false;
+			}
+		}
+	}
+
+	return true;
+}
+
+static void mremap_move_multiple_vmas(unsigned int pattern_seed,
+				      unsigned long page_size)
+{
+	char *test_name = "mremap move multiple vmas";
+	const size_t size = 11 * page_size;
+	bool success = true;
+	char *ptr, *tgt_ptr;
+	int i;
+
+	ptr = mmap(NULL, size, PROT_READ | PROT_WRITE,
+		   MAP_PRIVATE | MAP_ANON, -1, 0);
+	if (ptr == MAP_FAILED) {
+		perror("mmap");
+		success = false;
+		goto out;
+	}
+
+	tgt_ptr = mmap(NULL, 2 * size, PROT_READ | PROT_WRITE,
+		       MAP_PRIVATE | MAP_ANON, -1, 0);
+	if (tgt_ptr == MAP_FAILED) {
+		perror("mmap");
+		success = false;
+		goto out;
+	}
+	if (munmap(tgt_ptr, 2 * size)) {
+		perror("munmap");
+		success = false;
+		goto out_unmap;
+	}
+
+	/*
+	 * Unmap so we end up with:
+	 *
+	 *  0   2   4 5 6   8   10 offset in buffer
+	 * |*| |*| |*****| |*| |*|
+	 * |*| |*| |*****| |*| |*|
+	 *  0   1   2 3 4   5   6  pattern offset
+	 */
+	for (i = 1; i < 10; i += 2) {
+		if (i == 5)
+			continue;
+
+		if (munmap(&ptr[i * page_size], page_size)) {
+			perror("munmap");
+			success = false;
+			goto out_unmap;
+		}
+	}
+
+	srand(pattern_seed);
+
+	/* Set up random patterns. */
+	for (i = 0; i <= 10; i += 2) {
+		int j;
+		size_t size = i == 4 ? 2 * page_size : page_size;
+		char *buf = &ptr[i * page_size];
+
+		for (j = 0; j < size; j++)
+			buf[j] = rand();
+	}
+
+	/* First, just move the whole thing. */
+	if (mremap(ptr, size, size,
+		   MREMAP_MAYMOVE | MREMAP_FIXED, tgt_ptr) == MAP_FAILED) {
+		perror("mremap");
+		success = false;
+		goto out_unmap;
+	}
+	/* Check move was ok. */
+	if (!is_multiple_vma_range_ok(pattern_seed, tgt_ptr, page_size)) {
+		success = false;
+		goto out_unmap;
+	}
+
+	/* Move next to itself. */
+	if (mremap(tgt_ptr, size, size,
+		   MREMAP_MAYMOVE | MREMAP_FIXED, &tgt_ptr[size]) == MAP_FAILED) {
+		perror("mremap");
+		goto out_unmap;
+	}
+	/* Check that the move is ok. */
+	if (!is_multiple_vma_range_ok(pattern_seed, &tgt_ptr[size], page_size)) {
+		success = false;
+		goto out_unmap;
+	}
+
+	/* Map a range to overwrite. */
+	if (mmap(tgt_ptr, size, PROT_NONE,
+		 MAP_PRIVATE | MAP_ANON | MAP_FIXED, -1, 0) == MAP_FAILED) {
+		perror("mmap tgt");
+		success = false;
+		goto out_unmap;
+	}
+	/* Move and overwrite. */
+	if (mremap(&tgt_ptr[size], size, size,
+		   MREMAP_MAYMOVE | MREMAP_FIXED, tgt_ptr) == MAP_FAILED) {
+		perror("mremap");
+		goto out_unmap;
+	}
+	/* Check that the move is ok. */
+	if (!is_multiple_vma_range_ok(pattern_seed, tgt_ptr, page_size)) {
+		success = false;
+		goto out_unmap;
+	}
+
+out_unmap:
+	if (munmap(tgt_ptr, 2 * size))
+		perror("munmap tgt");
+	if (munmap(ptr, size))
+		perror("munmap src");
+
+out:
+	if (success)
+		ksft_test_result_pass("%s\n", test_name);
+	else
+		ksft_test_result_fail("%s\n", test_name);
+}
+
 /* Returns the time taken for the remap on success else returns -1. */
 static long long remap_region(struct config c, unsigned int threshold_mb,
 			      char *rand_addr)
@@ -721,7 +864,7 @@ int main(int argc, char **argv)
 	char *rand_addr;
 	size_t rand_size;
 	int num_expand_tests = 2;
-	int num_misc_tests = 2;
+	int num_misc_tests = 3;
 	struct test test_cases[MAX_TEST] = {};
 	struct test perf_test_cases[MAX_PERF_TEST];
 	int page_size;
@@ -848,6 +991,7 @@ int main(int argc, char **argv)
 
 	mremap_move_within_range(pattern_seed, rand_addr);
 	mremap_move_1mb_from_start(pattern_seed, rand_addr);
+	mremap_move_multiple_vmas(pattern_seed, page_size);
 
 	if (run_perf_tests) {
 		ksft_print_msg("\n%s\n",
-- 
2.50.0