Re: [PATCH v2 16/31] selftests/mm: UFFDIO_API test

[Mike Rapoport <rppt@linux.ibm.com>]

On Wed, Apr 12, 2023 at 12:42:57PM -0400, Peter Xu wrote:
> 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>

Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>

> ---
>  tools/testing/selftests/mm/uffd-unit-tests.c | 109 ++++++++++++++++++-
>  1 file changed, 108 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..bb492c258486 100644
> --- a/tools/testing/selftests/mm/uffd-unit-tests.c
> +++ b/tools/testing/selftests/mm/uffd-unit-tests.c
> @@ -9,9 +9,116 @@
> 
>  #ifdef __NR_userfaultfd
> 
> +static void uffd_test_report(void)
> +{
> +	printf("Userfaults unit tests: pass=%u, skip=%u, fail=%u (total=%u)\n",
> +	       ksft_get_pass_cnt(),
> +	       ksft_get_xskip_cnt(),
> +	       ksft_get_fail_cnt(),
> +	       ksft_test_num());
> +}
> +
> +static void uffd_test_pass(void)
> +{
> +	printf("done\n");
> +	ksft_inc_pass_cnt();
> +}
> +
> +#define  uffd_test_start(...)  do {		\
> +		printf("Testing ");		\
> +		printf(__VA_ARGS__);		\
> +		printf("... ");			\
> +		fflush(stdout);			\
> +	} while (0)
> +
> +#define  uffd_test_fail(...)  do {		\
> +		printf("failed [reason: ");	\
> +		printf(__VA_ARGS__);		\
> +		printf("]\n");			\
> +		ksft_inc_fail_cnt();		\
> +	} while (0)
> +
> +#define  uffd_test_skip(...)  do {		\
> +		printf("skipped [reason: ");	\
> +		printf(__VA_ARGS__);		\
> +		printf("]\n");			\
> +		ksft_inc_xskip_cnt();		\
> +	} 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 ksft_get_fail_cnt() ? KSFT_FAIL : KSFT_PASS;
>  }
> 
>  #else /* __NR_userfaultfd */
> -- 
> 2.39.1
> 

-- 
Sincerely yours,
Mike.