// SPDX-License-Identifier: GPL-2.0-only
/*
* COW (Copy On Write) tests.
*
* Copyright 2022, Red Hat, Inc.
*
* Author(s): David Hildenbrand <[email protected]>
*/
#define _GNU_SOURCE
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include <stdint.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <assert.h>
#include <linux/mman.h>
#include <sys/mman.h>
#include <sys/ioctl.h>
#include <sys/wait.h>
#include <linux/memfd.h>
#include "local_config.h"
#ifdef LOCAL_CONFIG_HAVE_LIBURING
#include <liburing.h>
#endif /* LOCAL_CONFIG_HAVE_LIBURING */
#include "../../../../mm/gup_test.h"
#include "../kselftest.h"
#include "vm_util.h"
#include "thp_settings.h"
static size_t pagesize;
static int pagemap_fd;
static size_t pmdsize;
static int nr_thpsizes;
static size_t thpsizes[20];
static int nr_hugetlbsizes;
static size_t hugetlbsizes[10];
static int gup_fd;
static bool has_huge_zeropage;
static int sz2ord(size_t size)
{
return __builtin_ctzll(size / pagesize);
}
static int detect_thp_sizes(size_t sizes[], int max)
{
int count = 0;
unsigned long orders;
size_t kb;
int i;
/* thp not supported at all. */
if (!pmdsize)
return 0;
orders = 1UL << sz2ord(pmdsize);
orders |= thp_supported_orders();
for (i = 0; orders && count < max; i++) {
if (!(orders & (1UL << i)))
continue;
orders &= ~(1UL << i);
kb = (pagesize >> 10) << i;
sizes[count++] = kb * 1024;
ksft_print_msg("[INFO] detected THP size: %zu KiB\n", kb);
}
return count;
}
static void detect_huge_zeropage(void)
{
int fd = open("/sys/kernel/mm/transparent_hugepage/use_zero_page",
O_RDONLY);
size_t enabled = 0;
char buf[15];
int ret;
if (fd < 0)
return;
ret = pread(fd, buf, sizeof(buf), 0);
if (ret > 0 && ret < sizeof(buf)) {
buf[ret] = 0;
enabled = strtoul(buf, NULL, 10);
if (enabled == 1) {
has_huge_zeropage = true;
ksft_print_msg("[INFO] huge zeropage is enabled\n");
}
}
close(fd);
}
static bool range_is_swapped(void *addr, size_t size)
{
for (; size; addr += pagesize, size -= pagesize)
if (!pagemap_is_swapped(pagemap_fd, addr))
return false;
return true;
}
struct comm_pipes {
int child_ready[2];
int parent_ready[2];
};
static int setup_comm_pipes(struct comm_pipes *comm_pipes)
{
if (pipe(comm_pipes->child_ready) < 0)
return -errno;
if (pipe(comm_pipes->parent_ready) < 0) {
close(comm_pipes->child_ready[0]);
close(comm_pipes->child_ready[1]);
return -errno;
}
return 0;
}
static void close_comm_pipes(struct comm_pipes *comm_pipes)
{
close(comm_pipes->child_ready[0]);
close(comm_pipes->child_ready[1]);
close(comm_pipes->parent_ready[0]);
close(comm_pipes->parent_ready[1]);
}
static int child_memcmp_fn(char *mem, size_t size,
struct comm_pipes *comm_pipes)
{
char *old = malloc(size);
char buf;
/* Backup the original content. */
memcpy(old, mem, size);
/* Wait until the parent modified the page. */
write(comm_pipes->child_ready[1], "0", 1);
while (read(comm_pipes->parent_ready[0], &buf, 1) != 1)
;
/* See if we still read the old values. */
return memcmp(old, mem, size);
}
static int child_vmsplice_memcmp_fn(char *mem, size_t size,
struct comm_pipes *comm_pipes)
{
struct iovec iov = {
.iov_base = mem,
.iov_len = size,
};
ssize_t cur, total, transferred;
char *old, *new;
int fds[2];
char buf;
old = malloc(size);
new = malloc(size);
/* Backup the original content. */
memcpy(old, mem, size);
if (pipe(fds) < 0)
return -errno;
/* Trigger a read-only pin. */
transferred = vmsplice(fds[1], &iov, 1, 0);
if (transferred < 0)
return -errno;
if (transferred == 0)
return -EINVAL;
/* Unmap it from our page tables. */
if (munmap(mem, size) < 0)
return -errno;
/* Wait until the parent modified it. */
write(comm_pipes->child_ready[1], "0", 1);
while (read(comm_pipes->parent_ready[0], &buf, 1) != 1)
;
/* See if we still read the old values via the pipe. */
for (total = 0; total < transferred; total += cur) {
cur = read(fds[0], new + total, transferred - total);
if (cur < 0)
return -errno;
}
return memcmp(old, new, transferred);
}
typedef int (*child_fn)(char *mem, size_t size, struct comm_pipes *comm_pipes);
static void do_test_cow_in_parent(char *mem, size_t size, bool do_mprotect,
child_fn fn, bool xfail)
{
struct comm_pipes comm_pipes;
char buf;
int ret;
ret = setup_comm_pipes(&comm_pipes);
if (ret) {
ksft_test_result_fail("pipe() failed\n");
return;
}
ret = fork();
if (ret < 0) {
ksft_test_result_fail("fork() failed\n");
goto close_comm_pipes;
} else if (!ret) {
exit(fn(mem, size, &comm_pipes));
}
while (read(comm_pipes.child_ready[0], &buf, 1) != 1)
;
if (do_mprotect) {
/*
* mprotect() optimizations might try avoiding
* write-faults by directly mapping pages writable.
*/
ret = mprotect(mem, size, PROT_READ);
ret |= mprotect(mem, size, PROT_READ|PROT_WRITE);
if (ret) {
ksft_test_result_fail("mprotect() failed\n");
write(comm_pipes.parent_ready[1], "0", 1);
wait(&ret);
goto close_comm_pipes;
}
}
/* Modify the page. */
memset(mem, 0xff, size);
write(comm_pipes.parent_ready[1], "0", 1);
wait(&ret);
if (WIFEXITED(ret))
ret = WEXITSTATUS(ret);
else
ret = -EINVAL;
if (!ret) {
ksft_test_result_pass("No leak from parent into child\n");
} else if (xfail) {
/*
* With hugetlb, some vmsplice() tests are currently expected to
* fail because (a) harder to fix and (b) nobody really cares.
* Flag them as expected failure for now.
*/
ksft_test_result_xfail("Leak from parent into child\n");
} else {
ksft_test_result_fail("Leak from parent into child\n");
}
close_comm_pipes:
close_comm_pipes(&comm_pipes);
}
static void test_cow_in_parent(char *mem, size_t size, bool is_hugetlb)
{
do_test_cow_in_parent(mem, size, false, child_memcmp_fn, false);
}
static void test_cow_in_parent_mprotect(char *mem, size_t size, bool is_hugetlb)
{
do_test_cow_in_parent(mem, size, true, child_memcmp_fn, false);
}
static void test_vmsplice_in_child(char *mem, size_t size, bool is_hugetlb)
{
do_test_cow_in_parent(mem, size, false, child_vmsplice_memcmp_fn,
is_hugetlb);
}
static void test_vmsplice_in_child_mprotect(char *mem, size_t size,
bool is_hugetlb)
{
do_test_cow_in_parent(mem, size, true, child_vmsplice_memcmp_fn,
is_hugetlb);
}
static void do_test_vmsplice_in_parent(char *mem, size_t size,
bool before_fork, bool xfail)
{
struct iovec iov = {
.iov_base = mem,
.iov_len = size,
};
ssize_t cur, total, transferred;
struct comm_pipes comm_pipes;
char *old, *new;
int ret, fds[2];
char buf;
old = malloc(size);
new = malloc(size);
memcpy(old, mem, size);
ret = setup_comm_pipes(&comm_pipes);
if (ret) {
ksft_test_result_fail("pipe() failed\n");
goto free;
}
if (pipe(fds) < 0) {
ksft_test_result_fail("pipe() failed\n");
goto close_comm_pipes;
}
if (before_fork) {
transferred = vmsplice(fds[1], &iov, 1, 0);
if (transferred <= 0) {
ksft_test_result_fail("vmsplice() failed\n");
goto close_pipe;
}
}
ret = fork();
if (ret < 0) {
ksft_test_result_fail("fork() failed\n");
goto close_pipe;
} else if (!ret) {
write(comm_pipes.child_ready[1], "0", 1);
while (read(comm_pipes.parent_ready[0], &buf, 1) != 1)
;
/* Modify page content in the child. */
memset(mem, 0xff, size);
exit(0);
}
if (!before_fork) {
transferred = vmsplice(fds[1], &iov, 1, 0);
if (transferred <= 0) {
ksft_test_result_fail("vmsplice() failed\n");
wait(&ret);
goto close_pipe;
}
}
while (read(comm_pipes.child_ready[0], &buf, 1) != 1)
;
if (munmap(mem, size) < 0) {
ksft_test_result_fail("munmap() failed\n");
goto close_pipe;
}
write(comm_pipes.parent_ready[1], "0", 1);
/* Wait until the child is done writing. */
wait(&ret);
if (!WIFEXITED(ret)) {
ksft_test_result_fail("wait() failed\n");
goto close_pipe;
}
/* See if we still read the old values. */
for (total = 0; total < transferred; total += cur) {
cur = read(fds[0], new + total, transferred - total);
if (cur < 0) {
ksft_test_result_fail("read() failed\n");
goto close_pipe;
}
}
if (!memcmp(old, new, transferred)) {
ksft_test_result_pass("No leak from child into parent\n");
} else if (xfail) {
/*
* With hugetlb, some vmsplice() tests are currently expected to
* fail because (a) harder to fix and (b) nobody really cares.
* Flag them as expected failure for now.
*/
ksft_test_result_xfail("Leak from child into parent\n");
} else {
ksft_test_result_fail("Leak from child into parent\n");
}
close_pipe:
close(fds[0]);
close(fds[1]);
close_comm_pipes:
close_comm_pipes(&comm_pipes);
free:
free(old);
free(new);
}
static void test_vmsplice_before_fork(char *mem, size_t size, bool is_hugetlb)
{
do_test_vmsplice_in_parent(mem, size, true, is_hugetlb);
}
static void test_vmsplice_after_fork(char *mem, size_t size, bool is_hugetlb)
{
do_test_vmsplice_in_parent(mem, size, false, is_hugetlb);
}
#ifdef LOCAL_CONFIG_HAVE_LIBURING
static void do_test_iouring(char *mem, size_t size, bool use_fork)
{
struct comm_pipes comm_pipes;
struct io_uring_cqe *cqe;
struct io_uring_sqe *sqe;
struct io_uring ring;
ssize_t cur, total;
struct iovec iov;
char *buf, *tmp;
int ret, fd;
FILE *file;
ret = setup_comm_pipes(&comm_pipes);
if (ret) {
ksft_test_result_fail("pipe() failed\n");
return;
}
file = tmpfile();
if (!file) {
ksft_test_result_fail("tmpfile() failed\n");
goto close_comm_pipes;
}
fd = fileno(file);
assert(fd);
tmp = malloc(size);
if (!tmp) {
ksft_test_result_fail("malloc() failed\n");
goto close_file;
}
/* Skip on errors, as we might just lack kernel support. */
ret = io_uring_queue_init(1, &ring, 0);
if (ret < 0) {
ksft_test_result_skip("io_uring_queue_init() failed\n");
goto free_tmp;
}
/*
* Register the range as a fixed buffer. This will FOLL_WRITE | FOLL_PIN
* | FOLL_LONGTERM the range.
*
* Skip on errors, as we might just lack kernel support or might not
* have sufficient MEMLOCK permissions.
*/
iov.iov_base = mem;
iov.iov_len = size;
ret = io_uring_register_buffers(&ring, &iov, 1);
if (ret) {
ksft_test_result_skip("io_uring_register_buffers() failed\n");
goto queue_exit;
}
if (use_fork) {
/*
* fork() and keep the child alive until we're done. Note that
* we expect the pinned page to not get shared with the child.
*/
ret = fork();
if (ret < 0) {
ksft_test_result_fail("fork() failed\n");
goto unregister_buffers;
} else if (!ret) {
write(comm_pipes.child_ready[1], "0", 1);
while (read(comm_pipes.parent_ready[0], &buf, 1) != 1)
;
exit(0);
}
while (read(comm_pipes.child_ready[0], &buf, 1) != 1)
;
} else {
/*
* Map the page R/O into the page table. Enable softdirty
* tracking to stop the page from getting mapped R/W immediately
* again by mprotect() optimizations. Note that we don't have an
* easy way to test if that worked (the pagemap does not export
* if the page is mapped R/O vs. R/W).
*/
ret = mprotect(mem, size, PROT_READ);
clear_softdirty();
ret |= mprotect(mem, size, PROT_READ | PROT_WRITE);
if (ret) {
ksft_test_result_fail("mprotect() failed\n");
goto unregister_buffers;
}
}
/*
* Modify the page and write page content as observed by the fixed
* buffer pin to the file so we can verify it.
*/
memset(mem, 0xff, size);
sqe = io_uring_get_sqe(&ring);
if (!sqe) {
ksft_test_result_fail("io_uring_get_sqe() failed\n");
goto quit_child;
}
io_uring_prep_write_fixed(sqe, fd, mem, size, 0, 0);
ret = io_uring_submit(&ring);
if (ret < 0) {
ksft_test_result_fail("io_uring_submit() failed\n");
goto quit_child;
}
ret = io_uring_wait_cqe(&ring, &cqe);
if (ret < 0) {
ksft_test_result_fail("io_uring_wait_cqe() failed\n");
goto quit_child;
}
if (cqe->res != size) {
ksft_test_result_fail("write_fixed failed\n");
goto quit_child;
}
io_uring_cqe_seen(&ring, cqe);
/* Read back the file content to the temporary buffer. */
total = 0;
while (total < size) {
cur = pread(fd, tmp + total, size - total, total);
if (cur < 0) {
ksft_test_result_fail("pread() failed\n");
goto quit_child;
}
total += cur;
}
/* Finally, check if we read what we expected. */
ksft_test_result(!memcmp(mem, tmp, size),
"Longterm R/W pin is reliable\n");
quit_child:
if (use_fork) {
write(comm_pipes.parent_ready[1], "0", 1);
wait(&ret);
}
unregister_buffers:
io_uring_unregister_buffers(&ring);
queue_exit:
io_uring_queue_exit(&ring);
free_tmp:
free(tmp);
close_file:
fclose(file);
close_comm_pipes:
close_comm_pipes(&comm_pipes);
}
static void test_iouring_ro(char *mem, size_t size, bool is_hugetlb)
{
do_test_iouring(mem, size, false);
}
static void test_iouring_fork(char *mem, size_t size, bool is_hugetlb)
{
do_test_iouring(mem, size, true);
}
#endif /* LOCAL_CONFIG_HAVE_LIBURING */
enum ro_pin_test {
RO_PIN_TEST,
RO_PIN_TEST_SHARED,
RO_PIN_TEST_PREVIOUSLY_SHARED,
RO_PIN_TEST_RO_EXCLUSIVE,
};
static void do_test_ro_pin(char *mem, size_t size, enum ro_pin_test test,
bool fast)
{
struct pin_longterm_test args;
struct comm_pipes comm_pipes;
char *tmp, buf;
__u64 tmp_val;
int ret;
if (gup_fd < 0) {
ksft_test_result_skip("gup_test not available\n");
return;
}
tmp = malloc(size);
if (!tmp) {
ksft_test_result_fail("malloc() failed\n");
return;
}
ret = setup_comm_pipes(&comm_pipes);
if (ret) {
ksft_test_result_fail("pipe() failed\n");
goto free_tmp;
}
switch (test) {
case RO_PIN_TEST:
break;
case RO_PIN_TEST_SHARED:
case RO_PIN_TEST_PREVIOUSLY_SHARED:
/*
* Share the pages with our child. As the pages are not pinned,
* this should just work.
*/
ret = fork();
if (ret < 0) {
ksft_test_result_fail("fork() failed\n");
goto close_comm_pipes;
} else if (!ret) {
write(comm_pipes.child_ready[1], "0", 1);
while (read(comm_pipes.parent_ready[0], &buf, 1) != 1)
;
exit(0);
}
/* Wait until our child is ready. */
while (read(comm_pipes.child_ready[0], &buf, 1) != 1)
;
if (test == RO_PIN_TEST_PREVIOUSLY_SHARED) {
/*
* Tell the child to quit now and wait until it quit.
* The pages should now be mapped R/O into our page
* tables, but they are no longer shared.
*/
write(comm_pipes.parent_ready[1], "0", 1);
wait(&ret);
if (!WIFEXITED(ret))
ksft_print_msg("[INFO] wait() failed\n");
}
break;
case RO_PIN_TEST_RO_EXCLUSIVE:
/*
* Map the page R/O into the page table. Enable softdirty
* tracking to stop the page from getting mapped R/W immediately
* again by mprotect() optimizations. Note that we don't have an
* easy way to test if that worked (the pagemap does not export
* if the page is mapped R/O vs. R/W).
*/
ret = mprotect(mem, size, PROT_READ);
clear_softdirty();
ret |= mprotect(mem, size, PROT_READ | PROT_WRITE);
if (ret) {
ksft_test_result_fail("mprotect() failed\n");
goto close_comm_pipes;
}
break;
default:
assert(false);
}
/* Take a R/O pin. This should trigger unsharing. */
args.addr = (__u64)(uintptr_t)mem;
args.size = size;
args.flags = fast ? PIN_LONGTERM_TEST_FLAG_USE_FAST : 0;
ret = ioctl(gup_fd, PIN_LONGTERM_TEST_START, &args);
if (ret) {
if (errno == EINVAL)
ksft_test_result_skip("PIN_LONGTERM_TEST_START failed\n");
else
ksft_test_result_fail("PIN_LONGTERM_TEST_START failed\n");
goto wait;
}
/* Modify the page. */
memset(mem, 0xff, size);
/*
* Read back the content via the pin to the temporary buffer and
* test if we observed the modification.
*/
tmp_val = (__u64)(uintptr_t)tmp;
ret = ioctl(gup_fd, PIN_LONGTERM_TEST_READ, &tmp_val);
if (ret)
ksft_test_result_fail("PIN_LONGTERM_TEST_READ failed\n");
else
ksft_test_result(!memcmp(mem, tmp, size),
"Longterm R/O pin is reliable\n");
ret = ioctl(gup_fd, PIN_LONGTERM_TEST_STOP);
if (ret)
ksft_print_msg("[INFO] PIN_LONGTERM_TEST_STOP failed\n");
wait:
switch (test) {
case RO_PIN_TEST_SHARED:
write(comm_pipes.parent_ready[1], "0", 1);
wait(&ret);
if (!WIFEXITED(ret))
ksft_print_msg("[INFO] wait() failed\n");
break;
default:
break;
}
close_comm_pipes:
close_comm_pipes(&comm_pipes);
free_tmp:
free(tmp);
}
static void test_ro_pin_on_shared(char *mem, size_t size, bool is_hugetlb)
{
do_test_ro_pin(mem, size, RO_PIN_TEST_SHARED, false);
}
static void test_ro_fast_pin_on_shared(char *mem, size_t size, bool is_hugetlb)
{
do_test_ro_pin(mem, size, RO_PIN_TEST_SHARED, true);
}
static void test_ro_pin_on_ro_previously_shared(char *mem, size_t size,
bool is_hugetlb)
{
do_test_ro_pin(mem, size, RO_PIN_TEST_PREVIOUSLY_SHARED, false);
}
static void test_ro_fast_pin_on_ro_previously_shared(char *mem, size_t size,
bool is_hugetlb)
{
do_test_ro_pin(mem, size, RO_PIN_TEST_PREVIOUSLY_SHARED, true);
}
static void test_ro_pin_on_ro_exclusive(char *mem, size_t size,
bool is_hugetlb)
{
do_test_ro_pin(mem, size, RO_PIN_TEST_RO_EXCLUSIVE, false);
}
static void test_ro_fast_pin_on_ro_exclusive(char *mem, size_t size,
bool is_hugetlb)
{
do_test_ro_pin(mem, size, RO_PIN_TEST_RO_EXCLUSIVE, true);
}
typedef void (*test_fn)(char *mem, size_t size, bool hugetlb);
static void do_run_with_base_page(test_fn fn, bool swapout)
{
char *mem;
int ret;
mem = mmap(NULL, pagesize, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
if (mem == MAP_FAILED) {
ksft_test_result_fail("mmap() failed\n");
return;
}
ret = madvise(mem, pagesize, MADV_NOHUGEPAGE);
/* Ignore if not around on a kernel. */
if (ret && errno != EINVAL) {
ksft_test_result_fail("MADV_NOHUGEPAGE failed\n");
goto munmap;
}
/* Populate a base page. */
memset(mem, 0, pagesize);
if (swapout) {
madvise(mem, pagesize, MADV_PAGEOUT);
if (!pagemap_is_swapped(pagemap_fd, mem)) {
ksft_test_result_skip("MADV_PAGEOUT did not work, is swap enabled?\n");
goto munmap;
}
}
fn(mem, pagesize, false);
munmap:
munmap(mem, pagesize);
}
static void run_with_base_page(test_fn fn, const char *desc)
{
ksft_print_msg("[RUN] %s ... with base page\n", desc);
do_run_with_base_page(fn, false);
}
static void run_with_base_page_swap(test_fn fn, const char *desc)
{
ksft_print_msg("[RUN] %s ... with swapped out base page\n", desc);
do_run_with_base_page(fn, true);
}
enum thp_run {
THP_RUN_PMD,
THP_RUN_PMD_SWAPOUT,
THP_RUN_PTE,
THP_RUN_PTE_SWAPOUT,
THP_RUN_SINGLE_PTE,
THP_RUN_SINGLE_PTE_SWAPOUT,
THP_RUN_PARTIAL_MREMAP,
THP_RUN_PARTIAL_SHARED,
};
static void do_run_with_thp(test_fn fn, enum thp_run thp_run, size_t thpsize)
{
char *mem, *mmap_mem, *tmp, *mremap_mem = MAP_FAILED;
size_t size, mmap_size, mremap_size;
int ret;
/* For alignment purposes, we need twice the thp size. */
mmap_size = 2 * thpsize;
mmap_mem = mmap(NULL, mmap_size, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
if (mmap_mem == MAP_FAILED) {
ksft_test_result_fail("mmap() failed\n");
return;
}
/* We need a THP-aligned memory area. */
mem = (char *)(((uintptr_t)mmap_mem + thpsize) & ~(thpsize - 1));
ret = madvise(mem, thpsize, MADV_HUGEPAGE);
if (ret) {
ksft_test_result_fail("MADV_HUGEPAGE failed\n");
goto munmap;
}
/*
* Try to populate a THP. Touch the first sub-page and test if
* we get the last sub-page populated automatically.
*/
mem[0] = 0;
if (!pagemap_is_populated(pagemap_fd, mem + thpsize - pagesize)) {
ksft_test_result_skip("Did not get a THP populated\n");
goto munmap;
}
memset(mem, 0, thpsize);
size = thpsize;
switch (thp_run) {
case THP_RUN_PMD:
case THP_RUN_PMD_SWAPOUT:
assert(thpsize == pmdsize);
break;
case THP_RUN_PTE:
case THP_RUN_PTE_SWAPOUT:
/*
* Trigger PTE-mapping the THP by temporarily mapping a single
* subpage R/O. This is a noop if the THP is not pmdsize (and
* therefore already PTE-mapped).
*/
ret = mprotect(mem + pagesize, pagesize, PROT_READ);
if (ret) {
ksft_test_result_fail("mprotect() failed\n");
goto munmap;
}
ret = mprotect(mem + pagesize, pagesize, PROT_READ | PROT_WRITE);
if (ret) {
ksft_test_result_fail("mprotect() failed\n");
goto munmap;
}
break;
case THP_RUN_SINGLE_PTE:
case THP_RUN_SINGLE_PTE_SWAPOUT:
/*
* Discard all but a single subpage of that PTE-mapped THP. What
* remains is a single PTE mapping a single subpage.
*/
ret = madvise(mem + pagesize, thpsize - pagesize, MADV_DONTNEED);
if (ret) {
ksft_test_result_fail("MADV_DONTNEED failed\n");
goto munmap;
}
size = pagesize;
break;
case THP_RUN_PARTIAL_MREMAP:
/*
* Remap half of the THP. We need some new memory location
* for that.
*/
mremap_size = thpsize / 2;
mremap_mem = mmap(NULL, mremap_size, PROT_NONE,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
if (mem == MAP_FAILED) {
ksft_test_result_fail("mmap() failed\n");
goto munmap;
}
tmp = mremap(mem + mremap_size, mremap_size, mremap_size,
MREMAP_MAYMOVE | MREMAP_FIXED, mremap_mem);
if (tmp != mremap_mem) {
ksft_test_result_fail("mremap() failed\n");
goto munmap;
}
size = mremap_size;
break;
case THP_RUN_PARTIAL_SHARED:
/*
* Share the first page of the THP with a child and quit the
* child. This will result in some parts of the THP never
* have been shared.
*/
ret = madvise(mem + pagesize, thpsize - pagesize, MADV_DONTFORK);
if (ret) {
ksft_test_result_fail("MADV_DONTFORK failed\n");
goto munmap;
}
ret = fork();
if (ret < 0) {
ksft_test_result_fail("fork() failed\n");
goto munmap;
} else if (!ret) {
exit(0);
}
wait(&ret);
/* Allow for sharing all pages again. */
ret = madvise(mem + pagesize, thpsize - pagesize, MADV_DOFORK);
if (ret) {
ksft_test_result_fail("MADV_DOFORK failed\n");
goto munmap;
}
break;
default:
assert(false);
}
switch (thp_run) {
case THP_RUN_PMD_SWAPOUT:
case THP_RUN_PTE_SWAPOUT:
case THP_RUN_SINGLE_PTE_SWAPOUT:
madvise(mem, size, MADV_PAGEOUT);
if (!range_is_swapped(mem, size)) {
ksft_test_result_skip("MADV_PAGEOUT did not work, is swap enabled?\n");
goto munmap;
}
break;
default:
break;
}
fn(mem, size, false);
munmap:
munmap(mmap_mem, mmap_size);
if (mremap_mem != MAP_FAILED)
munmap(mremap_mem, mremap_size);
}
static void run_with_thp(test_fn fn, const char *desc, size_t size)
{
ksft_print_msg("[RUN] %s ... with THP (%zu kB)\n",
desc, size / 1024);
do_run_with_thp(fn, THP_RUN_PMD, size);
}
static void run_with_thp_swap(test_fn fn, const char *desc, size_t size)
{
ksft_print_msg("[RUN] %s ... with swapped-out THP (%zu kB)\n",
desc, size / 1024);
do_run_with_thp(fn, THP_RUN_PMD_SWAPOUT, size);
}
static void run_with_pte_mapped_thp(test_fn fn, const char *desc, size_t size)
{
ksft_print_msg("[RUN] %s ... with PTE-mapped THP (%zu kB)\n",
desc, size / 1024);
do_run_with_thp(fn, THP_RUN_PTE, size);
}
static void run_with_pte_mapped_thp_swap(test_fn fn, const char *desc, size_t size)
{
ksft_print_msg("[RUN] %s ... with swapped-out, PTE-mapped THP (%zu kB)\n",
desc, size / 1024);
do_run_with_thp(fn, THP_RUN_PTE_SWAPOUT, size);
}
static void run_with_single_pte_of_thp(test_fn fn, const char *desc, size_t size)
{
ksft_print_msg("[RUN] %s ... with single PTE of THP (%zu kB)\n",
desc, size / 1024);
do_run_with_thp(fn, THP_RUN_SINGLE_PTE, size);
}
static void run_with_single_pte_of_thp_swap(test_fn fn, const char *desc, size_t size)
{
ksft_print_msg("[RUN] %s ... with single PTE of swapped-out THP (%zu kB)\n",
desc, size / 1024);
do_run_with_thp(fn, THP_RUN_SINGLE_PTE_SWAPOUT, size);
}
static void run_with_partial_mremap_thp(test_fn fn, const char *desc, size_t size)
{
ksft_print_msg("[RUN] %s ... with partially mremap()'ed THP (%zu kB)\n",
desc, size / 1024);
do_run_with_thp(fn, THP_RUN_PARTIAL_MREMAP, size);
}
static void run_with_partial_shared_thp(test_fn fn, const char *desc, size_t size)
{
ksft_print_msg("[RUN] %s ... with partially shared THP (%zu kB)\n",
desc, size / 1024);
do_run_with_thp(fn, THP_RUN_PARTIAL_SHARED, size);
}
static void run_with_hugetlb(test_fn fn, const char *desc, size_t hugetlbsize)
{
int flags = MAP_PRIVATE | MAP_ANONYMOUS | MAP_HUGETLB;
char *mem, *dummy;
ksft_print_msg("[RUN] %s ... with hugetlb (%zu kB)\n", desc,
hugetlbsize / 1024);
flags |= __builtin_ctzll(hugetlbsize) << MAP_HUGE_SHIFT;
mem = mmap(NULL, hugetlbsize, PROT_READ | PROT_WRITE, flags, -1, 0);
if (mem == MAP_FAILED) {
ksft_test_result_skip("need more free huge pages\n");
return;
}
/* Populate an huge page. */
memset(mem, 0, hugetlbsize);
/*
* We need a total of two hugetlb pages to handle COW/unsharing
* properly, otherwise we might get zapped by a SIGBUS.
*/
dummy = mmap(NULL, hugetlbsize, PROT_READ | PROT_WRITE, flags, -1, 0);
if (dummy == MAP_FAILED) {
ksft_test_result_skip("need more free huge pages\n");
goto munmap;
}
munmap(dummy, hugetlbsize);
fn(mem, hugetlbsize, true);
munmap:
munmap(mem, hugetlbsize);
}
struct test_case {
const char *desc;
test_fn fn;
};
/*
* Test cases that are specific to anonymous pages: pages in private mappings
* that may get shared via COW during fork().
*/
static const struct test_case anon_test_cases[] = {
/*
* Basic COW tests for fork() without any GUP. If we miss to break COW,
* either the child can observe modifications by the parent or the
* other way around.
*/
{
"Basic COW after fork()",
test_cow_in_parent,
},
/*
* Basic test, but do an additional mprotect(PROT_READ)+
* mprotect(PROT_READ|PROT_WRITE) in the parent before write access.
*/
{
"Basic COW after fork() with mprotect() optimization",
test_cow_in_parent_mprotect,
},
/*
* vmsplice() [R/O GUP] + unmap in the child; modify in the parent. If
* we miss to break COW, the child observes modifications by the parent.
* This is CVE-2020-29374 reported by Jann Horn.
*/
{
"vmsplice() + unmap in child",
test_vmsplice_in_child,
},
/*
* vmsplice() test, but do an additional mprotect(PROT_READ)+
* mprotect(PROT_READ|PROT_WRITE) in the parent before write access.
*/
{
"vmsplice() + unmap in child with mprotect() optimization",
test_vmsplice_in_child_mprotect,
},
/*
* vmsplice() [R/O GUP] in parent before fork(), unmap in parent after
* fork(); modify in the child. If we miss to break COW, the parent
* observes modifications by the child.
*/
{
"vmsplice() before fork(), unmap in parent after fork()",
test_vmsplice_before_fork,
},
/*
* vmsplice() [R/O GUP] + unmap in parent after fork(); modify in the
* child. If we miss to break COW, the parent observes modifications by
* the child.
*/
{
"vmsplice() + unmap in parent after fork()",
test_vmsplice_after_fork,
},
#ifdef LOCAL_CONFIG_HAVE_LIBURING
/*
* Take a R/W longterm pin and then map the page R/O into the page
* table to trigger a write fault on next access. When modifying the
* page, the page content must be visible via the pin.
*/
{
"R/O-mapping a page registered as iouring fixed buffer",
test_iouring_ro,
},
/*
* Take a R/W longterm pin and then fork() a child. When modifying the
* page, the page content must be visible via the pin. We expect the
* pinned page to not get shared with the child.
*/
{
"fork() with an iouring fixed buffer",
test_iouring_fork,
},
#endif /* LOCAL_CONFIG_HAVE_LIBURING */
/*
* Take a R/O longterm pin on a R/O-mapped shared anonymous page.
* When modifying the page via the page table, the page content change
* must be visible via the pin.
*/
{
"R/O GUP pin on R/O-mapped shared page",
test_ro_pin_on_shared,
},
/* Same as above, but using GUP-fast. */
{
"R/O GUP-fast pin on R/O-mapped shared page",
test_ro_fast_pin_on_shared,
},
/*
* Take a R/O longterm pin on a R/O-mapped exclusive anonymous page that
* was previously shared. When modifying the page via the page table,
* the page content change must be visible via the pin.
*/
{
"R/O GUP pin on R/O-mapped previously-shared page",
test_ro_pin_on_ro_previously_shared,
},
/* Same as above, but using GUP-fast. */
{
"R/O GUP-fast pin on R/O-mapped previously-shared page",
test_ro_fast_pin_on_ro_previously_shared,
},
/*
* Take a R/O longterm pin on a R/O-mapped exclusive anonymous page.
* When modifying the page via the page table, the page content change
* must be visible via the pin.
*/
{
"R/O GUP pin on R/O-mapped exclusive page",
test_ro_pin_on_ro_exclusive,
},
/* Same as above, but using GUP-fast. */
{
"R/O GUP-fast pin on R/O-mapped exclusive page",
test_ro_fast_pin_on_ro_exclusive,
},
};
static void run_anon_test_case(struct test_case const *test_case)
{
int i;
run_with_base_page(test_case->fn, test_case->desc);
run_with_base_page_swap(test_case->fn, test_case->desc);
for (i = 0; i < nr_thpsizes; i++) {
size_t size = thpsizes[i];
struct thp_settings settings = *thp_current_settings();
settings.hugepages[sz2ord(pmdsize)].enabled = THP_NEVER;
settings.hugepages[sz2ord(size)].enabled = THP_ALWAYS;
thp_push_settings(&settings);
if (size == pmdsize) {
run_with_thp(test_case->fn, test_case->desc, size);
run_with_thp_swap(test_case->fn, test_case->desc, size);
}
run_with_pte_mapped_thp(test_case->fn, test_case->desc, size);
run_with_pte_mapped_thp_swap(test_case->fn, test_case->desc, size);
run_with_single_pte_of_thp(test_case->fn, test_case->desc, size);
run_with_single_pte_of_thp_swap(test_case->fn, test_case->desc, size);
run_with_partial_mremap_thp(test_case->fn, test_case->desc, size);
run_with_partial_shared_thp(test_case->fn, test_case->desc, size);
thp_pop_settings();
}
for (i = 0; i < nr_hugetlbsizes; i++)
run_with_hugetlb(test_case->fn, test_case->desc,
hugetlbsizes[i]);
}
static void run_anon_test_cases(void)
{
int i;
ksft_print_msg("[INFO] Anonymous memory tests in private mappings\n");
for (i = 0; i < ARRAY_SIZE(anon_test_cases); i++)
run_anon_test_case(&anon_test_cases[i]);
}
static int tests_per_anon_test_case(void)
{
int tests = 2 + nr_hugetlbsizes;
tests += 6 * nr_thpsizes;
if (pmdsize)
tests += 2;
return tests;
}
enum anon_thp_collapse_test {
ANON_THP_COLLAPSE_UNSHARED,
ANON_THP_COLLAPSE_FULLY_SHARED,
ANON_THP_COLLAPSE_LOWER_SHARED,
ANON_THP_COLLAPSE_UPPER_SHARED,
};
static void do_test_anon_thp_collapse(char *mem, size_t size,
enum anon_thp_collapse_test test)
{
struct comm_pipes comm_pipes;
char buf;
int ret;
ret = setup_comm_pipes(&comm_pipes);
if (ret) {
ksft_test_result_fail("pipe() failed\n");
return;
}
/*
* Trigger PTE-mapping the THP by temporarily mapping a single subpage
* R/O, such that we can try collapsing it later.
*/
ret = mprotect(mem + pagesize, pagesize, PROT_READ);
if (ret) {
ksft_test_result_fail("mprotect() failed\n");
goto close_comm_pipes;
}
ret = mprotect(mem + pagesize, pagesize, PROT_READ | PROT_WRITE);
if (ret) {
ksft_test_result_fail("mprotect() failed\n");
goto close_comm_pipes;
}
switch (test) {
case ANON_THP_COLLAPSE_UNSHARED:
/* Collapse before actually COW-sharing the page. */
ret = madvise(mem, size, MADV_COLLAPSE);
if (ret) {
ksft_test_result_skip("MADV_COLLAPSE failed: %s\n",
strerror(errno));
goto close_comm_pipes;
}
break;
case ANON_THP_COLLAPSE_FULLY_SHARED:
/* COW-share the full PTE-mapped THP. */
break;
case ANON_THP_COLLAPSE_LOWER_SHARED:
/* Don't COW-share the upper part of the THP. */
ret = madvise(mem + size / 2, size / 2, MADV_DONTFORK);
if (ret) {
ksft_test_result_fail("MADV_DONTFORK failed\n");
goto close_comm_pipes;
}
break;
case ANON_THP_COLLAPSE_UPPER_SHARED:
/* Don't COW-share the lower part of the THP. */
ret = madvise(mem, size / 2, MADV_DONTFORK);
if (ret) {
ksft_test_result_fail("MADV_DONTFORK failed\n");
goto close_comm_pipes;
}
break;
default:
assert(false);
}
ret = fork();
if (ret < 0) {
ksft_test_result_fail("fork() failed\n");
goto close_comm_pipes;
} else if (!ret) {
switch (test) {
case ANON_THP_COLLAPSE_UNSHARED:
case ANON_THP_COLLAPSE_FULLY_SHARED:
exit(child_memcmp_fn(mem, size, &comm_pipes));
break;
case ANON_THP_COLLAPSE_LOWER_SHARED:
exit(child_memcmp_fn(mem, size / 2, &comm_pipes));
break;
case ANON_THP_COLLAPSE_UPPER_SHARED:
exit(child_memcmp_fn(mem + size / 2, size / 2,
&comm_pipes));
break;
default:
assert(false);
}
}
while (read(comm_pipes.child_ready[0], &buf, 1) != 1)
;
switch (test) {
case ANON_THP_COLLAPSE_UNSHARED:
break;
case ANON_THP_COLLAPSE_UPPER_SHARED:
case ANON_THP_COLLAPSE_LOWER_SHARED:
/*
* Revert MADV_DONTFORK such that we merge the VMAs and are
* able to actually collapse.
*/
ret = madvise(mem, size, MADV_DOFORK);
if (ret) {
ksft_test_result_fail("MADV_DOFORK failed\n");
write(comm_pipes.parent_ready[1], "0", 1);
wait(&ret);
goto close_comm_pipes;
}
/* FALLTHROUGH */
case ANON_THP_COLLAPSE_FULLY_SHARED:
/* Collapse before anyone modified the COW-shared page. */
ret = madvise(mem, size, MADV_COLLAPSE);
if (ret) {
ksft_test_result_skip("MADV_COLLAPSE failed: %s\n",
strerror(errno));
write(comm_pipes.parent_ready[1], "0", 1);
wait(&ret);
goto close_comm_pipes;
}
break;
default:
assert(false);
}
/* Modify the page. */
memset(mem, 0xff, size);
write(comm_pipes.parent_ready[1], "0", 1);
wait(&ret);
if (WIFEXITED(ret))
ret = WEXITSTATUS(ret);
else
ret = -EINVAL;
ksft_test_result(!ret, "No leak from parent into child\n");
close_comm_pipes:
close_comm_pipes(&comm_pipes);
}
static void test_anon_thp_collapse_unshared(char *mem, size_t size,
bool is_hugetlb)
{
assert(!is_hugetlb);
do_test_anon_thp_collapse(mem, size, ANON_THP_COLLAPSE_UNSHARED);
}
static void test_anon_thp_collapse_fully_shared(char *mem, size_t size,
bool is_hugetlb)
{
assert(!is_hugetlb);
do_test_anon_thp_collapse(mem, size, ANON_THP_COLLAPSE_FULLY_SHARED);
}
static void test_anon_thp_collapse_lower_shared(char *mem, size_t size,
bool is_hugetlb)
{
assert(!is_hugetlb);
do_test_anon_thp_collapse(mem, size, ANON_THP_COLLAPSE_LOWER_SHARED);
}
static void test_anon_thp_collapse_upper_shared(char *mem, size_t size,
bool is_hugetlb)
{
assert(!is_hugetlb);
do_test_anon_thp_collapse(mem, size, ANON_THP_COLLAPSE_UPPER_SHARED);
}
/*
* Test cases that are specific to anonymous THP: pages in private mappings
* that may get shared via COW during fork().
*/
static const struct test_case anon_thp_test_cases[] = {
/*
* Basic COW test for fork() without any GUP when collapsing a THP
* before fork().
*
* Re-mapping a PTE-mapped anon THP using a single PMD ("in-place
* collapse") might easily get COW handling wrong when not collapsing
* exclusivity information properly.
*/
{
"Basic COW after fork() when collapsing before fork()",
test_anon_thp_collapse_unshared,
},
/* Basic COW test, but collapse after COW-sharing a full THP. */
{
"Basic COW after fork() when collapsing after fork() (fully shared)",
test_anon_thp_collapse_fully_shared,
},
/*
* Basic COW test, but collapse after COW-sharing the lower half of a
* THP.
*/
{
"Basic COW after fork() when collapsing after fork() (lower shared)",
test_anon_thp_collapse_lower_shared,
},
/*
* Basic COW test, but collapse after COW-sharing the upper half of a
* THP.
*/
{
"Basic COW after fork() when collapsing after fork() (upper shared)",
test_anon_thp_collapse_upper_shared,
},
};
static void run_anon_thp_test_cases(void)
{
int i;
if (!pmdsize)
return;
ksft_print_msg("[INFO] Anonymous THP tests\n");
for (i = 0; i < ARRAY_SIZE(anon_thp_test_cases); i++) {
struct test_case const *test_case = &anon_thp_test_cases[i];
ksft_print_msg("[RUN] %s\n", test_case->desc);
do_run_with_thp(test_case->fn, THP_RUN_PMD, pmdsize);
}
}
static int tests_per_anon_thp_test_case(void)
{
return pmdsize ? 1 : 0;
}
typedef void (*non_anon_test_fn)(char *mem, const char *smem, size_t size);
static void test_cow(char *mem, const char *smem, size_t size)
{
char *old = malloc(size);
/* Backup the original content. */
memcpy(old, smem, size);
/* Modify the page. */
memset(mem, 0xff, size);
/* See if we still read the old values via the other mapping. */
ksft_test_result(!memcmp(smem, old, size),
"Other mapping not modified\n");
free(old);
}
static void test_ro_pin(char *mem, const char *smem, size_t size)
{
do_test_ro_pin(mem, size, RO_PIN_TEST, false);
}
static void test_ro_fast_pin(char *mem, const char *smem, size_t size)
{
do_test_ro_pin(mem, size, RO_PIN_TEST, true);
}
static void run_with_zeropage(non_anon_test_fn fn, const char *desc)
{
char *mem, *smem, tmp;
ksft_print_msg("[RUN] %s ... with shared zeropage\n", desc);
mem = mmap(NULL, pagesize, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANON, -1, 0);
if (mem == MAP_FAILED) {
ksft_test_result_fail("mmap() failed\n");
return;
}
smem = mmap(NULL, pagesize, PROT_READ, MAP_PRIVATE | MAP_ANON, -1, 0);
if (mem == MAP_FAILED) {
ksft_test_result_fail("mmap() failed\n");
goto munmap;
}
/* Read from the page to populate the shared zeropage. */
tmp = *mem + *smem;
asm volatile("" : "+r" (tmp));
fn(mem, smem, pagesize);
munmap:
munmap(mem, pagesize);
if (smem != MAP_FAILED)
munmap(smem, pagesize);
}
static void run_with_huge_zeropage(non_anon_test_fn fn, const char *desc)
{
char *mem, *smem, *mmap_mem, *mmap_smem, tmp;
size_t mmap_size;
int ret;
ksft_print_msg("[RUN] %s ... with huge zeropage\n", desc);
if (!has_huge_zeropage) {
ksft_test_result_skip("Huge zeropage not enabled\n");
return;
}
/* For alignment purposes, we need twice the thp size. */
mmap_size = 2 * pmdsize;
mmap_mem = mmap(NULL, mmap_size, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
if (mmap_mem == MAP_FAILED) {
ksft_test_result_fail("mmap() failed\n");
return;
}
mmap_smem = mmap(NULL, mmap_size, PROT_READ,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
if (mmap_smem == MAP_FAILED) {
ksft_test_result_fail("mmap() failed\n");
goto munmap;
}
/* We need a THP-aligned memory area. */
mem = (char *)(((uintptr_t)mmap_mem + pmdsize) & ~(pmdsize - 1));
smem = (char *)(((uintptr_t)mmap_smem + pmdsize) & ~(pmdsize - 1));
ret = madvise(mem, pmdsize, MADV_HUGEPAGE);
ret |= madvise(smem, pmdsize, MADV_HUGEPAGE);
if (ret) {
ksft_test_result_fail("MADV_HUGEPAGE failed\n");
goto munmap;
}
/*
* Read from the memory to populate the huge shared zeropage. Read from
* the first sub-page and test if we get another sub-page populated
* automatically.
*/
tmp = *mem + *smem;
asm volatile("" : "+r" (tmp));
if (!pagemap_is_populated(pagemap_fd, mem + pagesize) ||
!pagemap_is_populated(pagemap_fd, smem + pagesize)) {
ksft_test_result_skip("Did not get THPs populated\n");
goto munmap;
}
fn(mem, smem, pmdsize);
munmap:
munmap(mmap_mem, mmap_size);
if (mmap_smem != MAP_FAILED)
munmap(mmap_smem, mmap_size);
}
static void run_with_memfd(non_anon_test_fn fn, const char *desc)
{
char *mem, *smem, tmp;
int fd;
ksft_print_msg("[RUN] %s ... with memfd\n", desc);
fd = memfd_create("test", 0);
if (fd < 0) {
ksft_test_result_fail("memfd_create() failed\n");
return;
}
/* File consists of a single page filled with zeroes. */
if (fallocate(fd, 0, 0, pagesize)) {
ksft_test_result_fail("fallocate() failed\n");
goto close;
}
/* Create a private mapping of the memfd. */
mem = mmap(NULL, pagesize, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
if (mem == MAP_FAILED) {
ksft_test_result_fail("mmap() failed\n");
goto close;
}
smem = mmap(NULL, pagesize, PROT_READ, MAP_SHARED, fd, 0);
if (mem == MAP_FAILED) {
ksft_test_result_fail("mmap() failed\n");
goto munmap;
}
/* Fault the page in. */
tmp = *mem + *smem;
asm volatile("" : "+r" (tmp));
fn(mem, smem, pagesize);
munmap:
munmap(mem, pagesize);
if (smem != MAP_FAILED)
munmap(smem, pagesize);
close:
close(fd);
}
static void run_with_tmpfile(non_anon_test_fn fn, const char *desc)
{
char *mem, *smem, tmp;
FILE *file;
int fd;
ksft_print_msg("[RUN] %s ... with tmpfile\n", desc);
file = tmpfile();
if (!file) {
ksft_test_result_fail("tmpfile() failed\n");
return;
}
fd = fileno(file);
if (fd < 0) {
ksft_test_result_skip("fileno() failed\n");
return;
}
/* File consists of a single page filled with zeroes. */
if (fallocate(fd, 0, 0, pagesize)) {
ksft_test_result_fail("fallocate() failed\n");
goto close;
}
/* Create a private mapping of the memfd. */
mem = mmap(NULL, pagesize, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
if (mem == MAP_FAILED) {
ksft_test_result_fail("mmap() failed\n");
goto close;
}
smem = mmap(NULL, pagesize, PROT_READ, MAP_SHARED, fd, 0);
if (mem == MAP_FAILED) {
ksft_test_result_fail("mmap() failed\n");
goto munmap;
}
/* Fault the page in. */
tmp = *mem + *smem;
asm volatile("" : "+r" (tmp));
fn(mem, smem, pagesize);
munmap:
munmap(mem, pagesize);
if (smem != MAP_FAILED)
munmap(smem, pagesize);
close:
fclose(file);
}
static void run_with_memfd_hugetlb(non_anon_test_fn fn, const char *desc,
size_t hugetlbsize)
{
int flags = MFD_HUGETLB;
char *mem, *smem, tmp;
int fd;
ksft_print_msg("[RUN] %s ... with memfd hugetlb (%zu kB)\n", desc,
hugetlbsize / 1024);
flags |= __builtin_ctzll(hugetlbsize) << MFD_HUGE_SHIFT;
fd = memfd_create("test", flags);
if (fd < 0) {
ksft_test_result_skip("memfd_create() failed\n");
return;
}
/* File consists of a single page filled with zeroes. */
if (fallocate(fd, 0, 0, hugetlbsize)) {
ksft_test_result_skip("need more free huge pages\n");
goto close;
}
/* Create a private mapping of the memfd. */
mem = mmap(NULL, hugetlbsize, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd,
0);
if (mem == MAP_FAILED) {
ksft_test_result_skip("need more free huge pages\n");
goto close;
}
smem = mmap(NULL, hugetlbsize, PROT_READ, MAP_SHARED, fd, 0);
if (mem == MAP_FAILED) {
ksft_test_result_fail("mmap() failed\n");
goto munmap;
}
/* Fault the page in. */
tmp = *mem + *smem;
asm volatile("" : "+r" (tmp));
fn(mem, smem, hugetlbsize);
munmap:
munmap(mem, hugetlbsize);
if (mem != MAP_FAILED)
munmap(smem, hugetlbsize);
close:
close(fd);
}
struct non_anon_test_case {
const char *desc;
non_anon_test_fn fn;
};
/*
* Test cases that target any pages in private mappings that are not anonymous:
* pages that may get shared via COW ndependent of fork(). This includes
* the shared zeropage(s), pagecache pages, ...
*/
static const struct non_anon_test_case non_anon_test_cases[] = {
/*
* Basic COW test without any GUP. If we miss to break COW, changes are
* visible via other private/shared mappings.
*/
{
"Basic COW",
test_cow,
},
/*
* Take a R/O longterm pin. When modifying the page via the page table,
* the page content change must be visible via the pin.
*/
{
"R/O longterm GUP pin",
test_ro_pin,
},
/* Same as above, but using GUP-fast. */
{
"R/O longterm GUP-fast pin",
test_ro_fast_pin,
},
};
static void run_non_anon_test_case(struct non_anon_test_case const *test_case)
{
int i;
run_with_zeropage(test_case->fn, test_case->desc);
run_with_memfd(test_case->fn, test_case->desc);
run_with_tmpfile(test_case->fn, test_case->desc);
if (pmdsize)
run_with_huge_zeropage(test_case->fn, test_case->desc);
for (i = 0; i < nr_hugetlbsizes; i++)
run_with_memfd_hugetlb(test_case->fn, test_case->desc,
hugetlbsizes[i]);
}
static void run_non_anon_test_cases(void)
{
int i;
ksft_print_msg("[RUN] Non-anonymous memory tests in private mappings\n");
for (i = 0; i < ARRAY_SIZE(non_anon_test_cases); i++)
run_non_anon_test_case(&non_anon_test_cases[i]);
}
static int tests_per_non_anon_test_case(void)
{
int tests = 3 + nr_hugetlbsizes;
if (pmdsize)
tests += 1;
return tests;
}
int main(int argc, char **argv)
{
int err;
struct thp_settings default_settings;
ksft_print_header();
pagesize = getpagesize();
pmdsize = read_pmd_pagesize();
if (pmdsize) {
/* Only if THP is supported. */
thp_read_settings(&default_settings);
default_settings.hugepages[sz2ord(pmdsize)].enabled = THP_INHERIT;
thp_save_settings();
thp_push_settings(&default_settings);
ksft_print_msg("[INFO] detected PMD size: %zu KiB\n",
pmdsize / 1024);
nr_thpsizes = detect_thp_sizes(thpsizes, ARRAY_SIZE(thpsizes));
}
nr_hugetlbsizes = detect_hugetlb_page_sizes(hugetlbsizes,
ARRAY_SIZE(hugetlbsizes));
detect_huge_zeropage();
ksft_set_plan(ARRAY_SIZE(anon_test_cases) * tests_per_anon_test_case() +
ARRAY_SIZE(anon_thp_test_cases) * tests_per_anon_thp_test_case() +
ARRAY_SIZE(non_anon_test_cases) * tests_per_non_anon_test_case());
gup_fd = open("/sys/kernel/debug/gup_test", O_RDWR);
pagemap_fd = open("/proc/self/pagemap", O_RDONLY);
if (pagemap_fd < 0)
ksft_exit_fail_msg("opening pagemap failed\n");
run_anon_test_cases();
run_anon_thp_test_cases();
run_non_anon_test_cases();
if (pmdsize) {
/* Only if THP is supported. */
thp_restore_settings();
}
err = ksft_get_fail_cnt();
if (err)
ksft_exit_fail_msg("%d out of %d tests failed\n",
err, ksft_test_num());
ksft_exit_pass();
}
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