path: root/tools/testing/selftests/mm/uffd-unit-tests.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Userfaultfd unit tests.
 *
 *  Copyright (C) 2015-2023  Red Hat, Inc.
 */

#include <asm-generic/unistd.h>
#include "uffd-common.h"

#include "../../../../mm/gup_test.h"

/* The unit test doesn't need a large or random size, make it 32MB for now */
#define  UFFD_TEST_MEM_SIZE               (32UL << 20)

#define  MEM_ANON                         BIT_ULL(0)
#define  MEM_SHMEM                        BIT_ULL(1)
#define  MEM_SHMEM_PRIVATE                BIT_ULL(2)
#define  MEM_HUGETLB                      BIT_ULL(3)
#define  MEM_HUGETLB_PRIVATE              BIT_ULL(4)

#define  MEM_ALL  (MEM_ANON | MEM_SHMEM | MEM_SHMEM_PRIVATE | \
		   MEM_HUGETLB | MEM_HUGETLB_PRIVATE)

#define ALIGN_UP(x, align_to) \
	((__typeof__(x))((((unsigned long)(x)) + ((align_to)-1)) & ~((align_to)-1)))

struct mem_type {
	const char *name;
	unsigned int mem_flag;
	uffd_test_ops_t *mem_ops;
	bool shared;
};
typedef struct mem_type mem_type_t;

mem_type_t mem_types[] = {
	{
		.name = "anon",
		.mem_flag = MEM_ANON,
		.mem_ops = &anon_uffd_test_ops,
		.shared = false,
	},
	{
		.name = "shmem",
		.mem_flag = MEM_SHMEM,
		.mem_ops = &shmem_uffd_test_ops,
		.shared = true,
	},
	{
		.name = "shmem-private",
		.mem_flag = MEM_SHMEM_PRIVATE,
		.mem_ops = &shmem_uffd_test_ops,
		.shared = false,
	},
	{
		.name = "hugetlb",
		.mem_flag = MEM_HUGETLB,
		.mem_ops = &hugetlb_uffd_test_ops,
		.shared = true,
	},
	{
		.name = "hugetlb-private",
		.mem_flag = MEM_HUGETLB_PRIVATE,
		.mem_ops = &hugetlb_uffd_test_ops,
		.shared = false,
	},
};

/* Arguments to be passed over to each uffd unit test */
struct uffd_test_args {
	mem_type_t *mem_type;
};
typedef struct uffd_test_args uffd_test_args_t;

/* Returns: UFFD_TEST_* */
typedef void (*uffd_test_fn)(uffd_test_args_t *);

typedef struct {
	const char *name;
	uffd_test_fn uffd_fn;
	unsigned int mem_targets;
	uint64_t uffd_feature_required;
	uffd_test_case_ops_t *test_case_ops;
} uffd_test_case_t;

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)

static void uffd_test_skip(const char *message)
{
	printf("skipped [reason: %s]\n", message);
	ksft_inc_xskip_cnt();
}

/*
 * 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;
}

/*
 * This function initializes the global variables.  TODO: remove global
 * vars and then remove this.
 */
static int
uffd_setup_environment(uffd_test_args_t *args, uffd_test_case_t *test,
		       mem_type_t *mem_type, const char **errmsg)
{
	map_shared = mem_type->shared;
	uffd_test_ops = mem_type->mem_ops;
	uffd_test_case_ops = test->test_case_ops;

	if (mem_type->mem_flag & (MEM_HUGETLB_PRIVATE | MEM_HUGETLB))
		page_size = default_huge_page_size();
	else
		page_size = psize();

	nr_pages = UFFD_TEST_MEM_SIZE / page_size;
	/* TODO: remove this global var.. it's so ugly */
	nr_cpus = 1;

	/* Initialize test arguments */
	args->mem_type = mem_type;

	return uffd_test_ctx_init(test->uffd_feature_required, errmsg);
}

static bool uffd_feature_supported(uffd_test_case_t *test)
{
	uint64_t features;

	if (uffd_get_features(&features))
		return false;

	return (features & test->uffd_feature_required) ==
	    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)

typedef struct {
	int parent_uffd, child_uffd;
} fork_event_args;

static void *fork_event_consumer(void *data)
{
	fork_event_args *args = data;
	struct uffd_msg msg = { 0 };

	/* Read until a full msg received */
	while (uffd_read_msg(args->parent_uffd, &msg));

	if (msg.event != UFFD_EVENT_FORK)
		err("wrong message: %u\n", msg.event);

	/* Just to be properly freed later */
	args->child_uffd = msg.arg.fork.ufd;
	return NULL;
}

typedef struct {
	int gup_fd;
	bool pinned;
} pin_args;

/*
 * Returns 0 if succeed, <0 for errors.