[PATCH 16/29] selftests/mm: UFFDIO_API test

Peter Xu
2023-03-30T16:09:29Z

Add one simple test for UFFDIO_API. With that, I also added a bunch of
small but handy helpers along the way.

Signed-off-by: Peter Xu <peterx@redhat.com>
---
tools/testing/selftests/mm/uffd-unit-tests.c | 111 ++++++++++++++++++-
tools/testing/selftests/mm/vm_util.c | 10 ++
2 files changed, 120 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/mm/uffd-unit-tests.c b/tools/testing/selftests/mm/uffd-unit-tests.c
index 6857388783be..dfb44ffad5f5 100644
--- a/tools/testing/selftests/mm/uffd-unit-tests.c
+++ b/tools/testing/selftests/mm/uffd-unit-tests.c
@@ -9,9 +9,118 @@

#ifdef __NR_userfaultfd

+struct {
+ unsigned int pass, skip, fail, total;
+} uffd_test_acct;
+
+static void uffd_test_report(void)
+{
+ printf("Userfaults unit tests: pass=%u, skip=%u, fail=%u (total=%u)\n",
+ uffd_test_acct.pass,
+ uffd_test_acct.skip,
+ uffd_test_acct.fail,
+ uffd_test_acct.total);
+}
+
+static void uffd_test_pass(void)
+{
+ printf("done\n");
+ uffd_test_acct.pass++;
+}
+
+#define uffd_test_start(...) do { \
+ printf(__VA_ARGS__); \
+ printf("... "); \
+ uffd_test_acct.total++; \
+ } while (0)
+
+#define uffd_test_fail(...) do { \
+ printf("failed [reason: "); \
+ printf(__VA_ARGS__); \
+ printf("]\n"); \
+ uffd_test_acct.fail++; \
+ } while (0)
+
+#define uffd_test_skip(...) do { \
+ printf("skipped [reason: "); \
+ printf(__VA_ARGS__); \
+ printf("]\n"); \
+ uffd_test_acct.skip++; \
+ } while (0)
+
+/*
+ * Returns 1 if specific userfaultfd supported, 0 otherwise. Note, we'll
+ * return 1 even if some test failed as long as uffd supported, because in
+ * that case we still want to proceed with the rest uffd unit tests.
+ */
+static int test_uffd_api(bool use_dev)
+{
+ struct uffdio_api uffdio_api;
+ int uffd;
+
+ uffd_test_start("UFFDIO_API (with %s)",
+ use_dev ? "/dev/userfaultfd" : "syscall");
+
+ if (use_dev)
+ uffd = uffd_open_dev(UFFD_FLAGS);
+ else
+ uffd = uffd_open_sys(UFFD_FLAGS);
+ if (uffd < 0) {
+ uffd_test_skip("cannot open userfaultfd handle");
+ return 0;
+ }
+
+ /* Test wrong UFFD_API */
+ uffdio_api.api = 0xab;
+ uffdio_api.features = 0;
+ if (ioctl(uffd, UFFDIO_API, &uffdio_api) == 0) {
+ uffd_test_fail("UFFDIO_API should fail with wrong api but didn't");
+ goto out;
+ }
+
+ /* Test wrong feature bit */
+ uffdio_api.api = UFFD_API;
+ uffdio_api.features = BIT_ULL(63);
+ if (ioctl(uffd, UFFDIO_API, &uffdio_api) == 0) {
+ uffd_test_fail("UFFDIO_API should fail with wrong feature but didn't");
+ goto out;
+ }
+
+ /* Test normal UFFDIO_API */
+ uffdio_api.api = UFFD_API;
+ uffdio_api.features = 0;
+ if (ioctl(uffd, UFFDIO_API, &uffdio_api)) {
+ uffd_test_fail("UFFDIO_API should succeed but failed");
+ goto out;
+ }
+
+ /* Test double requests of UFFDIO_API with a random feature set */
+ uffdio_api.features = BIT_ULL(0);
+ if (ioctl(uffd, UFFDIO_API, &uffdio_api) == 0) {
+ uffd_test_fail("UFFDIO_API should reject initialized uffd");
+ goto out;
+ }
+
+ uffd_test_pass();
+out:
+ close(uffd);
+ /* We have a valid uffd handle */
+ return 1;
+}
+
int main(int argc, char *argv[])
{
- return KSFT_PASS;
+ int has_uffd;
+
+ has_uffd = test_uffd_api(false);
+ has_uffd |= test_uffd_api(true);
+
+ if (!has_uffd) {
+ printf("Userfaultfd not supported or unprivileged, skip all tests\n");
+ exit(KSFT_SKIP);
+ }
+ uffd_test_report();
+ return uffd_test_acct.fail ? KSFT_FAIL : KSFT_PASS;
}

#else /* __NR_userfaultfd */
diff --git a/tools/testing/selftests/mm/vm_util.c b/tools/testing/selftests/mm/vm_util.c
index 7c2bf88d6393..62fcf039d6b7 100644
--- a/tools/testing/selftests/mm/vm_util.c
+++ b/tools/testing/selftests/mm/vm_util.c
@@ -254,3 +254,13 @@ int uffd_open_sys(unsigned int flags)
return -1;
#endif
}
+
+int uffd_open(unsigned int flags)
+{
+ int uffd = uffd_open_sys(flags);
+
+ if (uffd < 0)
+ uffd = uffd_open_dev(flags);
+
+ return uffd;
+}
--
2.39.1