[PATCH 5/5] userfaultfd/selftests: exercise minor fault handling shmem support

[Axel Rasmussen <axelrasmussen@google.com>]

Enable test_uffdio_minor for test_type == TEST_SHMEM, and modify the
test slightly to pass in / check for the right feature flags.

Signed-off-by: Axel Rasmussen <axelrasmussen@google.com>
---
 tools/testing/selftests/vm/userfaultfd.c | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/tools/testing/selftests/vm/userfaultfd.c b/tools/testing/selftests/vm/userfaultfd.c
index 5183ddb3080d..f31e9a4edc55 100644
--- a/tools/testing/selftests/vm/userfaultfd.c
+++ b/tools/testing/selftests/vm/userfaultfd.c
@@ -1410,7 +1410,7 @@ static int userfaultfd_minor_test(void)
 	void *expected_page;
 	char c;
 	struct uffd_stats stats = { 0 };
-	uint64_t features = UFFD_FEATURE_MINOR_HUGETLBFS;
+	uint64_t req_features, features_out;
 
 	if (!test_uffdio_minor)
 		return 0;
@@ -1418,10 +1418,18 @@ static int userfaultfd_minor_test(void)
 	printf("testing minor faults: ");
 	fflush(stdout);
 
-	if (uffd_test_ctx_clear() || uffd_test_ctx_init_ext(&features))
+	if (test_type == TEST_HUGETLB)
+		req_features = UFFD_FEATURE_MINOR_HUGETLBFS;
+	else if (test_type == TEST_SHMEM)
+		req_features = UFFD_FEATURE_MINOR_SHMEM;
+	else
+		return 1;
+
+	features_out = req_features;
+	if (uffd_test_ctx_clear() || uffd_test_ctx_init_ext(&features_out))
 		return 1;
-	/* If kernel reports the feature isn't supported, skip the test. */
-	if (!(features & UFFD_FEATURE_MINOR_HUGETLBFS)) {
+	/* If kernel reports required features aren't supported, skip test. */
+	if ((features_out & req_features) != req_features) {
 		printf("skipping test due to lack of feature support\n");
 		fflush(stdout);
 		return 0;
@@ -1431,7 +1439,7 @@ static int userfaultfd_minor_test(void)
 	uffdio_register.range.len = nr_pages * page_size;
 	uffdio_register.mode = UFFDIO_REGISTER_MODE_MINOR;
 	if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register)) {
-		fprintf(stderr, "register failure\n");
+		perror("register failure");
 		exit(1);
 	}
 
@@ -1695,6 +1703,7 @@ static void set_test_type(const char *type)
 		map_shared = true;
 		test_type = TEST_SHMEM;
 		uffd_test_ops = &shmem_uffd_test_ops;
+		test_uffdio_minor = true;
 	} else {
 		fprintf(stderr, "Unknown test type: %s\n", type); exit(1);
 	}
-- 
2.30.0.617.g56c4b15f3c-goog