Commit 8bda424f authored by Peter Xu's avatar Peter Xu Committed by Andrew Morton
Browse files

selftests/mm: move uffd pagemap test to unit test 

Move it over and make it split into two tests, one for pagemap and one for
the new WP_UNPOPULATED (to be a separate one).

The thp pagemap test wasn't really working (with MADV_HUGEPAGE).  Let's
just drop it (since it never really worked anyway..) and leave that for
later.

Link: https://lkml.kernel.org/r/20230412164352.328733-1-peterx@redhat.com


Signed-off-by: default avatarPeter Xu <peterx@redhat.com>
Reviewed-by: default avatarMike Rapoport (IBM) <rppt@kernel.org>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Zach O'Keefe <zokeefe@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 16a45b57

tools/testing/selftests/mm/uffd-stress.c

+0 −166
Original line number Diff line number Diff line
@@ -670,157 +670,6 @@ static int userfaultfd_minor_test(void) 
	return args.missing_faults != 0 || args.minor_faults != nr_pages;

}



static int pagemap_open(void)

{

	int fd = open("/proc/self/pagemap", O_RDONLY);



	if (fd < 0)

		err("open pagemap");



	return fd;

}



/* This macro let __LINE__ works in err() */

#define  pagemap_check_wp(value, wp) do {				\

		if (!!(value & PM_UFFD_WP) != wp)			\

			err("pagemap uffd-wp bit error: 0x%"PRIx64, value); \

	} while (0)



static int pagemap_test_fork(bool present)

{

	pid_t child = fork();

	uint64_t value;

	int fd, result;



	if (!child) {

		/* Open the pagemap fd of the child itself */

		fd = pagemap_open();

		value = pagemap_get_entry(fd, area_dst);

		/*

		 * After fork() uffd-wp bit should be gone as long as we're

		 * without UFFD_FEATURE_EVENT_FORK

		 */

		pagemap_check_wp(value, false);

		/* Succeed */

		exit(0);

	}

	waitpid(child, &result, 0);

	return result;

}



static void userfaultfd_wp_unpopulated_test(int pagemap_fd)

{

	uint64_t value;



	/* Test applying pte marker to anon unpopulated */

	wp_range(uffd, (uint64_t)area_dst, page_size, true);

	value = pagemap_get_entry(pagemap_fd, area_dst);

	pagemap_check_wp(value, true);



	/* Test unprotect on anon pte marker */

	wp_range(uffd, (uint64_t)area_dst, page_size, false);

	value = pagemap_get_entry(pagemap_fd, area_dst);

	pagemap_check_wp(value, false);



	/* Test zap on anon marker */

	wp_range(uffd, (uint64_t)area_dst, page_size, true);

	if (madvise(area_dst, page_size, MADV_DONTNEED))

		err("madvise(MADV_DONTNEED) failed");

	value = pagemap_get_entry(pagemap_fd, area_dst);

	pagemap_check_wp(value, false);



	/* Test fault in after marker removed */

	*area_dst = 1;

	value = pagemap_get_entry(pagemap_fd, area_dst);

	pagemap_check_wp(value, false);

	/* Drop it to make pte none again */

	if (madvise(area_dst, page_size, MADV_DONTNEED))

		err("madvise(MADV_DONTNEED) failed");



	/* Test read-zero-page upon pte marker */

	wp_range(uffd, (uint64_t)area_dst, page_size, true);

	*(volatile char *)area_dst;

	/* Drop it to make pte none again */

	if (madvise(area_dst, page_size, MADV_DONTNEED))

		err("madvise(MADV_DONTNEED) failed");

}



static void userfaultfd_pagemap_test(unsigned int test_pgsize)

{

	int pagemap_fd;

	uint64_t value;



	/* Pagemap tests uffd-wp only */

	if (!test_uffdio_wp)

		return;



	/* Not enough memory to test this page size */

	if (test_pgsize > nr_pages * page_size)

		return;



	printf("testing uffd-wp with pagemap (pgsize=%u): ", test_pgsize);

	/* Flush so it doesn't flush twice in parent/child later */

	fflush(stdout);



	uffd_test_ctx_init(UFFD_FEATURE_WP_UNPOPULATED);



	if (test_pgsize > page_size) {

		/* This is a thp test */

		if (madvise(area_dst, nr_pages * page_size, MADV_HUGEPAGE))

			err("madvise(MADV_HUGEPAGE) failed");

	} else if (test_pgsize == page_size) {

		/* This is normal page test; force no thp */

		if (madvise(area_dst, nr_pages * page_size, MADV_NOHUGEPAGE))

			err("madvise(MADV_NOHUGEPAGE) failed");

	}



	if (uffd_register(uffd, area_dst, nr_pages * page_size,

			  false, true, false))

		err("register failed");



	pagemap_fd = pagemap_open();



	/* Smoke test WP_UNPOPULATED first when it's still empty */

	if (test_pgsize == page_size)

		userfaultfd_wp_unpopulated_test(pagemap_fd);



	/* Touch the page */

	*area_dst = 1;

	wp_range(uffd, (uint64_t)area_dst, test_pgsize, true);

	value = pagemap_get_entry(pagemap_fd, area_dst);

	pagemap_check_wp(value, true);

	/* Make sure uffd-wp bit dropped when fork */

	if (pagemap_test_fork(true))

		err("Detected stall uffd-wp bit in child");



	/* Exclusive required or PAGEOUT won't work */

	if (!(value & PM_MMAP_EXCLUSIVE))

		err("multiple mapping detected: 0x%"PRIx64, value);



	if (madvise(area_dst, test_pgsize, MADV_PAGEOUT))

		err("madvise(MADV_PAGEOUT) failed");



	/* Uffd-wp should persist even swapped out */

	value = pagemap_get_entry(pagemap_fd, area_dst);

	pagemap_check_wp(value, true);

	/* Make sure uffd-wp bit dropped when fork */

	if (pagemap_test_fork(false))

		err("Detected stall uffd-wp bit in child");



	/* Unprotect; this tests swap pte modifications */

	wp_range(uffd, (uint64_t)area_dst, page_size, false);

	value = pagemap_get_entry(pagemap_fd, area_dst);

	pagemap_check_wp(value, false);



	/* Fault in the page from disk */

	*area_dst = 2;

	value = pagemap_get_entry(pagemap_fd, area_dst);

	pagemap_check_wp(value, false);



	close(pagemap_fd);

	printf("done\n");

}



static int userfaultfd_stress(void)

{

	void *area;
@@ -932,21 +781,6 @@ static int userfaultfd_stress(void) 
		uffd_stats_report(args, nr_cpus);

	}



	if (test_type == TEST_ANON) {

		/*

		 * shmem/hugetlb won't be able to run since they have different

		 * behavior on fork() (file-backed memory normally drops ptes

		 * directly when fork), meanwhile the pagemap test will verify

		 * pgtable entry of fork()ed child.

		 */

		userfaultfd_pagemap_test(page_size);

		/*

		 * Hard-code for x86_64 for now for 2M THP, as x86_64 is

		 * currently the only one that supports uffd-wp

		 */

		userfaultfd_pagemap_test(page_size * 512);

	}



	return userfaultfd_zeropage_test() || userfaultfd_sig_test()

		|| userfaultfd_events_test() || userfaultfd_minor_test();

}

tools/testing/selftests/mm/uffd-unit-tests.c

+145 −0
Original line number Diff line number Diff line
@@ -197,7 +197,152 @@ static bool uffd_feature_supported(uffd_test_case_t *test) 
	    test->uffd_feature_required;

}



static int pagemap_open(void)

{

	int fd = open("/proc/self/pagemap", O_RDONLY);



	if (fd < 0)

		err("open pagemap");



	return fd;

}



/* This macro let __LINE__ works in err() */

#define  pagemap_check_wp(value, wp) do {				\

		if (!!(value & PM_UFFD_WP) != wp)			\

			err("pagemap uffd-wp bit error: 0x%"PRIx64, value); \

	} while (0)



static int pagemap_test_fork(bool present)

{

	pid_t child = fork();

	uint64_t value;

	int fd, result;



	if (!child) {

		/* Open the pagemap fd of the child itself */

		fd = pagemap_open();

		value = pagemap_get_entry(fd, area_dst);

		/*

		 * After fork() uffd-wp bit should be gone as long as we're

		 * without UFFD_FEATURE_EVENT_FORK

		 */

		pagemap_check_wp(value, false);

		/* Succeed */

		exit(0);

	}

	waitpid(child, &result, 0);

	return result;

}



static void uffd_wp_unpopulated_test(void)

{

	uint64_t value;

	int pagemap_fd;



	if (uffd_register(uffd, area_dst, nr_pages * page_size,

			  false, true, false))

		err("register failed");



	pagemap_fd = pagemap_open();



	/* Test applying pte marker to anon unpopulated */

	wp_range(uffd, (uint64_t)area_dst, page_size, true);

	value = pagemap_get_entry(pagemap_fd, area_dst);

	pagemap_check_wp(value, true);



	/* Test unprotect on anon pte marker */

	wp_range(uffd, (uint64_t)area_dst, page_size, false);

	value = pagemap_get_entry(pagemap_fd, area_dst);

	pagemap_check_wp(value, false);



	/* Test zap on anon marker */

	wp_range(uffd, (uint64_t)area_dst, page_size, true);

	if (madvise(area_dst, page_size, MADV_DONTNEED))

		err("madvise(MADV_DONTNEED) failed");

	value = pagemap_get_entry(pagemap_fd, area_dst);

	pagemap_check_wp(value, false);



	/* Test fault in after marker removed */

	*area_dst = 1;

	value = pagemap_get_entry(pagemap_fd, area_dst);

	pagemap_check_wp(value, false);

	/* Drop it to make pte none again */

	if (madvise(area_dst, page_size, MADV_DONTNEED))

		err("madvise(MADV_DONTNEED) failed");



	/* Test read-zero-page upon pte marker */

	wp_range(uffd, (uint64_t)area_dst, page_size, true);

	*(volatile char *)area_dst;

	/* Drop it to make pte none again */

	if (madvise(area_dst, page_size, MADV_DONTNEED))

		err("madvise(MADV_DONTNEED) failed");



	uffd_test_pass();

}



static void uffd_pagemap_test(void)

{

	int pagemap_fd;

	uint64_t value;



	if (uffd_register(uffd, area_dst, nr_pages * page_size,

			  false, true, false))

		err("register failed");



	pagemap_fd = pagemap_open();



	/* Touch the page */

	*area_dst = 1;

	wp_range(uffd, (uint64_t)area_dst, page_size, true);

	value = pagemap_get_entry(pagemap_fd, area_dst);

	pagemap_check_wp(value, true);

	/* Make sure uffd-wp bit dropped when fork */

	if (pagemap_test_fork(true))

		err("Detected stall uffd-wp bit in child");



	/* Exclusive required or PAGEOUT won't work */

	if (!(value & PM_MMAP_EXCLUSIVE))

		err("multiple mapping detected: 0x%"PRIx64, value);



	if (madvise(area_dst, page_size, MADV_PAGEOUT))

		err("madvise(MADV_PAGEOUT) failed");



	/* Uffd-wp should persist even swapped out */

	value = pagemap_get_entry(pagemap_fd, area_dst);

	pagemap_check_wp(value, true);

	/* Make sure uffd-wp bit dropped when fork */

	if (pagemap_test_fork(false))

		err("Detected stall uffd-wp bit in child");



	/* Unprotect; this tests swap pte modifications */

	wp_range(uffd, (uint64_t)area_dst, page_size, false);

	value = pagemap_get_entry(pagemap_fd, area_dst);

	pagemap_check_wp(value, false);



	/* Fault in the page from disk */

	*area_dst = 2;

	value = pagemap_get_entry(pagemap_fd, area_dst);

	pagemap_check_wp(value, false);



	close(pagemap_fd);

	uffd_test_pass();

}



uffd_test_case_t uffd_tests[] = {

	{

		.name = "pagemap",

		.uffd_fn = uffd_pagemap_test,

		.mem_targets = MEM_ANON,

		.uffd_feature_required = UFFD_FEATURE_PAGEFAULT_FLAG_WP,

	},

	{

		.name = "wp-unpopulated",

		.uffd_fn = uffd_wp_unpopulated_test,

		.mem_targets = MEM_ANON,

		.uffd_feature_required =

		UFFD_FEATURE_PAGEFAULT_FLAG_WP | UFFD_FEATURE_WP_UNPOPULATED,

	},

};



int main(int argc, char *argv[])