protection_keys_32
protection_keys_64
madv_populate
-userfaultfd
+uffd-stress
+uffd-unit-tests
mlock-intersect-test
mlock-random-test
virtual_address_range
# Avoid accidental wrong builds, due to built-in rules working just a little
# bit too well--but not quite as well as required for our situation here.
#
-# In other words, "make userfaultfd" is supposed to fail to build at all,
+# In other words, "make $SOME_TEST" is supposed to fail to build at all,
# because this Makefile only supports either "make" (all), or "make /full/path".
# However, the built-in rules, if not suppressed, will pick up CFLAGS and the
# initial LDLIBS (but not the target-specific LDLIBS, because those are only
TEST_GEN_PROGS += on-fault-limit
TEST_GEN_PROGS += thuge-gen
TEST_GEN_PROGS += transhuge-stress
-TEST_GEN_PROGS += userfaultfd
+TEST_GEN_PROGS += uffd-stress
+TEST_GEN_PROGS += uffd-unit-tests
TEST_GEN_PROGS += soft-dirty
TEST_GEN_PROGS += split_huge_page_test
TEST_GEN_PROGS += ksm_tests
$(TEST_GEN_PROGS): vm_util.c
-$(OUTPUT)/userfaultfd: uffd-common.c
+$(OUTPUT)/uffd-stress: uffd-common.c
+$(OUTPUT)/uffd-unit-tests: uffd-common.c
ifeq ($(MACHINE),x86_64)
BINARIES_32 := $(patsubst %,$(OUTPUT)/%,$(BINARIES_32))
# Dump pages 0, 19, and 4096, using pin_user_pages:
CATEGORY="gup_test" run_test ./gup_test -ct -F 0x1 0 19 0x1000
+CATEGORY="userfaultfd" run_test ./uffd-unit-tests
uffd_mods=("" ":dev")
+uffd_stress_bin=./uffd-stress
for mod in "${uffd_mods[@]}"; do
- CATEGORY="userfaultfd" run_test ./userfaultfd anon${mod} 20 16
+ CATEGORY="userfaultfd" run_test ${uffd_stress_bin} anon${mod} 20 16
# Hugetlb tests require source and destination huge pages. Pass in half
# the size ($half_ufd_size_MB), which is used for *each*.
- CATEGORY="userfaultfd" run_test ./userfaultfd hugetlb${mod} "$half_ufd_size_MB" 32
- CATEGORY="userfaultfd" run_test ./userfaultfd hugetlb_shared${mod} "$half_ufd_size_MB" 32
- CATEGORY="userfaultfd" run_test ./userfaultfd shmem${mod} 20 16
+ CATEGORY="userfaultfd" run_test ${uffd_stress_bin} hugetlb${mod} "$half_ufd_size_MB" 32
+ CATEGORY="userfaultfd" run_test ${uffd_stress_bin} hugetlb_shared${mod} "$half_ufd_size_MB" 32
+ CATEGORY="userfaultfd" run_test ${uffd_stress_bin} shmem${mod} 20 16
done
#cleanup
--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Stress userfaultfd syscall.
+ *
+ * Copyright (C) 2015 Red Hat, Inc.
+ *
+ * This test allocates two virtual areas and bounces the physical
+ * memory across the two virtual areas (from area_src to area_dst)
+ * using userfaultfd.
+ *
+ * There are three threads running per CPU:
+ *
+ * 1) one per-CPU thread takes a per-page pthread_mutex in a random
+ * page of the area_dst (while the physical page may still be in
+ * area_src), and increments a per-page counter in the same page,
+ * and checks its value against a verification region.
+ *
+ * 2) another per-CPU thread handles the userfaults generated by
+ * thread 1 above. userfaultfd blocking reads or poll() modes are
+ * exercised interleaved.
+ *
+ * 3) one last per-CPU thread transfers the memory in the background
+ * at maximum bandwidth (if not already transferred by thread
+ * 2). Each cpu thread takes cares of transferring a portion of the
+ * area.
+ *
+ * When all threads of type 3 completed the transfer, one bounce is
+ * complete. area_src and area_dst are then swapped. All threads are
+ * respawned and so the bounce is immediately restarted in the
+ * opposite direction.
+ *
+ * per-CPU threads 1 by triggering userfaults inside
+ * pthread_mutex_lock will also verify the atomicity of the memory
+ * transfer (UFFDIO_COPY).
+ */
+
+#include "uffd-common.h"
+
+#ifdef __NR_userfaultfd
+
+#define BOUNCE_RANDOM (1<<0)
+#define BOUNCE_RACINGFAULTS (1<<1)
+#define BOUNCE_VERIFY (1<<2)
+#define BOUNCE_POLL (1<<3)
+static int bounces;
+
+/* exercise the test_uffdio_*_eexist every ALARM_INTERVAL_SECS */
+#define ALARM_INTERVAL_SECS 10
+static char *zeropage;
+pthread_attr_t attr;
+
+#define swap(a, b) \
+ do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0)
+
+#define factor_of_2(x) ((x) ^ ((x) & ((x) - 1)))
+
+const char *examples =
+ "# Run anonymous memory test on 100MiB region with 99999 bounces:\n"
+ "./userfaultfd anon 100 99999\n\n"
+ "# Run the same anonymous memory test, but using /dev/userfaultfd:\n"
+ "./userfaultfd anon:dev 100 99999\n\n"
+ "# Run share memory test on 1GiB region with 99 bounces:\n"
+ "./userfaultfd shmem 1000 99\n\n"
+ "# Run hugetlb memory test on 256MiB region with 50 bounces:\n"
+ "./userfaultfd hugetlb 256 50\n\n"
+ "# Run the same hugetlb test but using shared file:\n"
+ "./userfaultfd hugetlb_shared 256 50\n\n"
+ "# 10MiB-~6GiB 999 bounces anonymous test, "
+ "continue forever unless an error triggers\n"
+ "while ./userfaultfd anon $[RANDOM % 6000 + 10] 999; do true; done\n\n";
+
+static void usage(void)
+{
+ fprintf(stderr, "\nUsage: ./userfaultfd <test type> <MiB> <bounces> "
+ "[hugetlbfs_file]\n\n");
+ fprintf(stderr, "Supported <test type>: anon, hugetlb, "
+ "hugetlb_shared, shmem\n\n");
+ fprintf(stderr, "'Test mods' can be joined to the test type string with a ':'. "
+ "Supported mods:\n");
+ fprintf(stderr, "\tsyscall - Use userfaultfd(2) (default)\n");
+ fprintf(stderr, "\tdev - Use /dev/userfaultfd instead of userfaultfd(2)\n");
+ fprintf(stderr, "\tcollapse - Test MADV_COLLAPSE of UFFDIO_REGISTER_MODE_MINOR\n"
+ "memory\n");
+ fprintf(stderr, "\nExample test mod usage:\n");
+ fprintf(stderr, "# Run anonymous memory test with /dev/userfaultfd:\n");
+ fprintf(stderr, "./userfaultfd anon:dev 100 99999\n\n");
+
+ fprintf(stderr, "Examples:\n\n");
+ fprintf(stderr, "%s", examples);
+ exit(1);
+}
+
+static void uffd_stats_reset(struct uffd_stats *uffd_stats,
+ unsigned long n_cpus)
+{
+ int i;
+
+ for (i = 0; i < n_cpus; i++) {
+ uffd_stats[i].cpu = i;
+ uffd_stats[i].missing_faults = 0;
+ uffd_stats[i].wp_faults = 0;
+ uffd_stats[i].minor_faults = 0;
+ }
+}
+
+static inline uint64_t uffd_minor_feature(void)
+{
+ if (test_type == TEST_HUGETLB && map_shared)
+ return UFFD_FEATURE_MINOR_HUGETLBFS;
+ else if (test_type == TEST_SHMEM)
+ return UFFD_FEATURE_MINOR_SHMEM;
+ else
+ return 0;
+}
+
+static int my_bcmp(char *str1, char *str2, size_t n)
+{
+ unsigned long i;
+ for (i = 0; i < n; i++)
+ if (str1[i] != str2[i])
+ return 1;
+ return 0;
+}
+
+static void *locking_thread(void *arg)
+{
+ unsigned long cpu = (unsigned long) arg;
+ unsigned long page_nr;
+ unsigned long long count;
+
+ if (!(bounces & BOUNCE_RANDOM)) {
+ page_nr = -bounces;
+ if (!(bounces & BOUNCE_RACINGFAULTS))
+ page_nr += cpu * nr_pages_per_cpu;
+ }
+
+ while (!finished) {
+ if (bounces & BOUNCE_RANDOM) {
+ if (getrandom(&page_nr, sizeof(page_nr), 0) != sizeof(page_nr))
+ err("getrandom failed");
+ } else
+ page_nr += 1;
+ page_nr %= nr_pages;
+ pthread_mutex_lock(area_mutex(area_dst, page_nr));
+ count = *area_count(area_dst, page_nr);
+ if (count != count_verify[page_nr])
+ err("page_nr %lu memory corruption %llu %llu",
+ page_nr, count, count_verify[page_nr]);
+ count++;
+ *area_count(area_dst, page_nr) = count_verify[page_nr] = count;
+ pthread_mutex_unlock(area_mutex(area_dst, page_nr));
+ }
+
+ return NULL;
+}
+
+static int copy_page_retry(int ufd, unsigned long offset)
+{
+ return __copy_page(ufd, offset, true);
+}
+
+pthread_mutex_t uffd_read_mutex = PTHREAD_MUTEX_INITIALIZER;
+
+static void *uffd_read_thread(void *arg)
+{
+ struct uffd_stats *stats = (struct uffd_stats *)arg;
+ struct uffd_msg msg;
+
+ pthread_mutex_unlock(&uffd_read_mutex);
+ /* from here cancellation is ok */
+
+ for (;;) {
+ if (uffd_read_msg(uffd, &msg))
+ continue;
+ uffd_handle_page_fault(&msg, stats);
+ }
+
+ return NULL;
+}
+
+static void *background_thread(void *arg)
+{
+ unsigned long cpu = (unsigned long) arg;
+ unsigned long page_nr, start_nr, mid_nr, end_nr;
+
+ start_nr = cpu * nr_pages_per_cpu;
+ end_nr = (cpu+1) * nr_pages_per_cpu;
+ mid_nr = (start_nr + end_nr) / 2;
+
+ /* Copy the first half of the pages */
+ for (page_nr = start_nr; page_nr < mid_nr; page_nr++)
+ copy_page_retry(uffd, page_nr * page_size);
+
+ /*
+ * If we need to test uffd-wp, set it up now. Then we'll have
+ * at least the first half of the pages mapped already which
+ * can be write-protected for testing
+ */
+ if (test_uffdio_wp)
+ wp_range(uffd, (unsigned long)area_dst + start_nr * page_size,
+ nr_pages_per_cpu * page_size, true);
+
+ /*
+ * Continue the 2nd half of the page copying, handling write
+ * protection faults if any
+ */
+ for (page_nr = mid_nr; page_nr < end_nr; page_nr++)
+ copy_page_retry(uffd, page_nr * page_size);
+
+ return NULL;
+}
+
+static int stress(struct uffd_stats *uffd_stats)
+{
+ unsigned long cpu;
+ pthread_t locking_threads[nr_cpus];
+ pthread_t uffd_threads[nr_cpus];
+ pthread_t background_threads[nr_cpus];
+
+ finished = 0;
+ for (cpu = 0; cpu < nr_cpus; cpu++) {
+ if (pthread_create(&locking_threads[cpu], &attr,
+ locking_thread, (void *)cpu))
+ return 1;
+ if (bounces & BOUNCE_POLL) {
+ if (pthread_create(&uffd_threads[cpu], &attr,
+ uffd_poll_thread,
+ (void *)&uffd_stats[cpu]))
+ return 1;
+ } else {
+ if (pthread_create(&uffd_threads[cpu], &attr,
+ uffd_read_thread,
+ (void *)&uffd_stats[cpu]))
+ return 1;
+ pthread_mutex_lock(&uffd_read_mutex);
+ }
+ if (pthread_create(&background_threads[cpu], &attr,
+ background_thread, (void *)cpu))
+ return 1;
+ }
+ for (cpu = 0; cpu < nr_cpus; cpu++)
+ if (pthread_join(background_threads[cpu], NULL))
+ return 1;
+
+ /*
+ * Be strict and immediately zap area_src, the whole area has
+ * been transferred already by the background treads. The
+ * area_src could then be faulted in a racy way by still
+ * running uffdio_threads reading zeropages after we zapped
+ * area_src (but they're guaranteed to get -EEXIST from
+ * UFFDIO_COPY without writing zero pages into area_dst
+ * because the background threads already completed).
+ */
+ uffd_test_ops->release_pages(area_src);
+
+ finished = 1;
+ for (cpu = 0; cpu < nr_cpus; cpu++)
+ if (pthread_join(locking_threads[cpu], NULL))
+ return 1;
+
+ for (cpu = 0; cpu < nr_cpus; cpu++) {
+ char c;
+ if (bounces & BOUNCE_POLL) {
+ if (write(pipefd[cpu*2+1], &c, 1) != 1)
+ err("pipefd write error");
+ if (pthread_join(uffd_threads[cpu],
+ (void *)&uffd_stats[cpu]))
+ return 1;
+ } else {
+ if (pthread_cancel(uffd_threads[cpu]))
+ return 1;
+ if (pthread_join(uffd_threads[cpu], NULL))
+ return 1;
+ }
+ }
+
+ return 0;
+}
+
+sigjmp_buf jbuf, *sigbuf;
+
+static void sighndl(int sig, siginfo_t *siginfo, void *ptr)
+{
+ if (sig == SIGBUS) {
+ if (sigbuf)
+ siglongjmp(*sigbuf, 1);
+ abort();
+ }
+}
+
+/*
+ * For non-cooperative userfaultfd test we fork() a process that will
+ * generate pagefaults, will mremap the area monitored by the
+ * userfaultfd and at last this process will release the monitored
+ * area.
+ * For the anonymous and shared memory the area is divided into two
+ * parts, the first part is accessed before mremap, and the second
+ * part is accessed after mremap. Since hugetlbfs does not support
+ * mremap, the entire monitored area is accessed in a single pass for
+ * HUGETLB_TEST.
+ * The release of the pages currently generates event for shmem and
+ * anonymous memory (UFFD_EVENT_REMOVE), hence it is not checked
+ * for hugetlb.
+ * For signal test(UFFD_FEATURE_SIGBUS), signal_test = 1, we register
+ * monitored area, generate pagefaults and test that signal is delivered.
+ * Use UFFDIO_COPY to allocate missing page and retry. For signal_test = 2
+ * test robustness use case - we release monitored area, fork a process
+ * that will generate pagefaults and verify signal is generated.
+ * This also tests UFFD_FEATURE_EVENT_FORK event along with the signal
+ * feature. Using monitor thread, verify no userfault events are generated.
+ */
+static int faulting_process(int signal_test)
+{
+ unsigned long nr;
+ unsigned long long count;
+ unsigned long split_nr_pages;
+ unsigned long lastnr;
+ struct sigaction act;
+ volatile unsigned long signalled = 0;
+
+ split_nr_pages = (nr_pages + 1) / 2;
+
+ if (signal_test) {
+ sigbuf = &jbuf;
+ memset(&act, 0, sizeof(act));
+ act.sa_sigaction = sighndl;
+ act.sa_flags = SA_SIGINFO;
+ if (sigaction(SIGBUS, &act, 0))
+ err("sigaction");
+ lastnr = (unsigned long)-1;
+ }
+
+ for (nr = 0; nr < split_nr_pages; nr++) {
+ volatile int steps = 1;
+ unsigned long offset = nr * page_size;
+
+ if (signal_test) {
+ if (sigsetjmp(*sigbuf, 1) != 0) {
+ if (steps == 1 && nr == lastnr)
+ err("Signal repeated");
+
+ lastnr = nr;
+ if (signal_test == 1) {
+ if (steps == 1) {
+ /* This is a MISSING request */
+ steps++;
+ if (copy_page(uffd, offset))
+ signalled++;
+ } else {
+ /* This is a WP request */
+ assert(steps == 2);
+ wp_range(uffd,
+ (__u64)area_dst +
+ offset,
+ page_size, false);
+ }
+ } else {
+ signalled++;
+ continue;
+ }
+ }
+ }
+
+ count = *area_count(area_dst, nr);
+ if (count != count_verify[nr])
+ err("nr %lu memory corruption %llu %llu\n",
+ nr, count, count_verify[nr]);
+ /*
+ * Trigger write protection if there is by writing
+ * the same value back.
+ */
+ *area_count(area_dst, nr) = count;
+ }
+
+ if (signal_test)
+ return signalled != split_nr_pages;
+
+ area_dst = mremap(area_dst, nr_pages * page_size, nr_pages * page_size,
+ MREMAP_MAYMOVE | MREMAP_FIXED, area_src);
+ if (area_dst == MAP_FAILED)
+ err("mremap");
+ /* Reset area_src since we just clobbered it */
+ area_src = NULL;
+
+ for (; nr < nr_pages; nr++) {
+ count = *area_count(area_dst, nr);
+ if (count != count_verify[nr]) {
+ err("nr %lu memory corruption %llu %llu\n",
+ nr, count, count_verify[nr]);
+ }
+ /*
+ * Trigger write protection if there is by writing
+ * the same value back.
+ */
+ *area_count(area_dst, nr) = count;
+ }
+
+ uffd_test_ops->release_pages(area_dst);
+
+ for (nr = 0; nr < nr_pages; nr++)
+ if (my_bcmp(area_dst + nr * page_size, zeropage, page_size))
+ err("nr %lu is not zero", nr);
+
+ return 0;
+}
+
+static void retry_uffdio_zeropage(int ufd,
+ struct uffdio_zeropage *uffdio_zeropage,
+ unsigned long offset)
+{
+ uffd_test_ops->alias_mapping(&uffdio_zeropage->range.start,
+ uffdio_zeropage->range.len,
+ offset);
+ if (ioctl(ufd, UFFDIO_ZEROPAGE, uffdio_zeropage)) {
+ if (uffdio_zeropage->zeropage != -EEXIST)
+ err("UFFDIO_ZEROPAGE error: %"PRId64,
+ (int64_t)uffdio_zeropage->zeropage);
+ } else {
+ err("UFFDIO_ZEROPAGE error: %"PRId64,
+ (int64_t)uffdio_zeropage->zeropage);
+ }
+}
+
+static int __uffdio_zeropage(int ufd, unsigned long offset)
+{
+ struct uffdio_zeropage uffdio_zeropage;
+ int ret;
+ bool has_zeropage = !(test_type == TEST_HUGETLB);
+ __s64 res;
+
+ if (offset >= nr_pages * page_size)
+ err("unexpected offset %lu", offset);
+ uffdio_zeropage.range.start = (unsigned long) area_dst + offset;
+ uffdio_zeropage.range.len = page_size;
+ uffdio_zeropage.mode = 0;
+ ret = ioctl(ufd, UFFDIO_ZEROPAGE, &uffdio_zeropage);
+ res = uffdio_zeropage.zeropage;
+ if (ret) {
+ /* real retval in ufdio_zeropage.zeropage */
+ if (has_zeropage)
+ err("UFFDIO_ZEROPAGE error: %"PRId64, (int64_t)res);
+ else if (res != -EINVAL)
+ err("UFFDIO_ZEROPAGE not -EINVAL");
+ } else if (has_zeropage) {
+ if (res != page_size) {
+ err("UFFDIO_ZEROPAGE unexpected size");
+ } else {
+ retry_uffdio_zeropage(ufd, &uffdio_zeropage,
+ offset);
+ return 1;
+ }
+ } else
+ err("UFFDIO_ZEROPAGE succeeded");
+
+ return 0;
+}
+
+static int uffdio_zeropage(int ufd, unsigned long offset)
+{
+ return __uffdio_zeropage(ufd, offset);
+}
+
+/* exercise UFFDIO_ZEROPAGE */
+static int userfaultfd_zeropage_test(void)
+{
+ struct uffdio_register uffdio_register;
+
+ printf("testing UFFDIO_ZEROPAGE: ");
+ fflush(stdout);
+
+ uffd_test_ctx_init(0);
+
+ uffdio_register.range.start = (unsigned long) area_dst;
+ uffdio_register.range.len = nr_pages * page_size;
+ uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
+ if (test_uffdio_wp)
+ uffdio_register.mode |= UFFDIO_REGISTER_MODE_WP;
+ if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register))
+ err("register failure");
+
+ assert_expected_ioctls_present(
+ uffdio_register.mode, uffdio_register.ioctls);
+
+ if (area_dst_alias) {
+ /* Needed this to test zeropage-retry on shared memory */
+ uffdio_register.range.start = (unsigned long) area_dst_alias;
+ if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register))
+ err("register failure");
+ }
+
+ if (uffdio_zeropage(uffd, 0))
+ if (my_bcmp(area_dst, zeropage, page_size))
+ err("zeropage is not zero");
+
+ printf("done.\n");
+ return 0;
+}
+
+static int userfaultfd_events_test(void)
+{
+ struct uffdio_register uffdio_register;
+ pthread_t uffd_mon;
+ int err, features;
+ pid_t pid;
+ char c;
+ struct uffd_stats stats = { 0 };
+
+ printf("testing events (fork, remap, remove): ");
+ fflush(stdout);
+
+ features = UFFD_FEATURE_EVENT_FORK | UFFD_FEATURE_EVENT_REMAP |
+ UFFD_FEATURE_EVENT_REMOVE;
+ uffd_test_ctx_init(features);
+
+ fcntl(uffd, F_SETFL, uffd_flags | O_NONBLOCK);
+
+ uffdio_register.range.start = (unsigned long) area_dst;
+ uffdio_register.range.len = nr_pages * page_size;
+ uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
+ if (test_uffdio_wp)
+ uffdio_register.mode |= UFFDIO_REGISTER_MODE_WP;
+ if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register))
+ err("register failure");
+
+ assert_expected_ioctls_present(
+ uffdio_register.mode, uffdio_register.ioctls);
+
+ if (pthread_create(&uffd_mon, &attr, uffd_poll_thread, &stats))
+ err("uffd_poll_thread create");
+
+ pid = fork();
+ if (pid < 0)
+ err("fork");
+
+ if (!pid)
+ exit(faulting_process(0));
+
+ waitpid(pid, &err, 0);
+ if (err)
+ err("faulting process failed");
+ if (write(pipefd[1], &c, sizeof(c)) != sizeof(c))
+ err("pipe write");
+ if (pthread_join(uffd_mon, NULL))
+ return 1;
+
+ uffd_stats_report(&stats, 1);
+
+ return stats.missing_faults != nr_pages;
+}
+
+static int userfaultfd_sig_test(void)
+{
+ struct uffdio_register uffdio_register;
+ unsigned long userfaults;
+ pthread_t uffd_mon;
+ int err, features;
+ pid_t pid;
+ char c;
+ struct uffd_stats stats = { 0 };
+
+ printf("testing signal delivery: ");
+ fflush(stdout);
+
+ features = UFFD_FEATURE_EVENT_FORK|UFFD_FEATURE_SIGBUS;
+ uffd_test_ctx_init(features);
+
+ fcntl(uffd, F_SETFL, uffd_flags | O_NONBLOCK);
+
+ uffdio_register.range.start = (unsigned long) area_dst;
+ uffdio_register.range.len = nr_pages * page_size;
+ uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
+ if (test_uffdio_wp)
+ uffdio_register.mode |= UFFDIO_REGISTER_MODE_WP;
+ if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register))
+ err("register failure");
+
+ assert_expected_ioctls_present(
+ uffdio_register.mode, uffdio_register.ioctls);
+
+ if (faulting_process(1))
+ err("faulting process failed");
+
+ uffd_test_ops->release_pages(area_dst);
+
+ if (pthread_create(&uffd_mon, &attr, uffd_poll_thread, &stats))
+ err("uffd_poll_thread create");
+
+ pid = fork();
+ if (pid < 0)
+ err("fork");
+
+ if (!pid)
+ exit(faulting_process(2));
+
+ waitpid(pid, &err, 0);
+ if (err)
+ err("faulting process failed");
+ if (write(pipefd[1], &c, sizeof(c)) != sizeof(c))
+ err("pipe write");
+ if (pthread_join(uffd_mon, (void **)&userfaults))
+ return 1;
+
+ printf("done.\n");
+ if (userfaults)
+ err("Signal test failed, userfaults: %ld", userfaults);
+
+ return userfaults != 0;
+}
+
+void check_memory_contents(char *p)
+{
+ unsigned long i;
+ uint8_t expected_byte;
+ void *expected_page;
+
+ if (posix_memalign(&expected_page, page_size, page_size))
+ err("out of memory");
+
+ for (i = 0; i < nr_pages; ++i) {
+ expected_byte = ~((uint8_t)(i % ((uint8_t)-1)));
+ memset(expected_page, expected_byte, page_size);
+ if (my_bcmp(expected_page, p + (i * page_size), page_size))
+ err("unexpected page contents after minor fault");
+ }
+
+ free(expected_page);
+}
+
+static int userfaultfd_minor_test(void)
+{
+ unsigned long p;
+ struct uffdio_register uffdio_register;
+ pthread_t uffd_mon;
+ char c;
+ struct uffd_stats stats = { 0 };
+
+ if (!test_uffdio_minor)
+ return 0;
+
+ printf("testing minor faults: ");
+ fflush(stdout);
+
+ uffd_test_ctx_init(uffd_minor_feature());
+
+ uffdio_register.range.start = (unsigned long)area_dst_alias;
+ uffdio_register.range.len = nr_pages * page_size;
+ uffdio_register.mode = UFFDIO_REGISTER_MODE_MINOR;
+ if (test_uffdio_wp)
+ uffdio_register.mode |= UFFDIO_REGISTER_MODE_WP;
+ if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register))
+ err("register failure");
+
+ assert_expected_ioctls_present(
+ uffdio_register.mode, uffdio_register.ioctls);
+
+ /*
+ * After registering with UFFD, populate the non-UFFD-registered side of
+ * the shared mapping. This should *not* trigger any UFFD minor faults.
+ */
+ for (p = 0; p < nr_pages; ++p) {
+ memset(area_dst + (p * page_size), p % ((uint8_t)-1),
+ page_size);
+ }
+
+ if (pthread_create(&uffd_mon, &attr, uffd_poll_thread, &stats))
+ err("uffd_poll_thread create");
+
+ /*
+ * Read each of the pages back using the UFFD-registered mapping. We
+ * expect that the first time we touch a page, it will result in a minor
+ * fault. uffd_poll_thread will resolve the fault by bit-flipping the
+ * page's contents, and then issuing a CONTINUE ioctl.
+ */
+ check_memory_contents(area_dst_alias);
+
+ if (write(pipefd[1], &c, sizeof(c)) != sizeof(c))
+ err("pipe write");
+ if (pthread_join(uffd_mon, NULL))
+ return 1;
+
+ uffd_stats_report(&stats, 1);
+
+ if (test_collapse) {
+ printf("testing collapse of uffd memory into PMD-mapped THPs:");
+ if (madvise(area_dst_alias, nr_pages * page_size,
+ MADV_COLLAPSE))
+ err("madvise(MADV_COLLAPSE)");
+
+ uffd_test_ops->check_pmd_mapping(area_dst,
+ nr_pages * page_size /
+ hpage_size);
+ /*
+ * This won't cause uffd-fault - it purely just makes sure there
+ * was no corruption.
+ */
+ check_memory_contents(area_dst_alias);
+ printf(" done.\n");
+ }
+
+ return stats.missing_faults != 0 || stats.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)
+{
+ struct uffdio_register uffdio_register;
+ 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");
+ }
+
+ uffdio_register.range.start = (unsigned long) area_dst;
+ uffdio_register.range.len = nr_pages * page_size;
+ uffdio_register.mode = UFFDIO_REGISTER_MODE_WP;
+ if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register))
+ 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;
+ unsigned long nr;
+ struct uffdio_register uffdio_register;
+ struct uffd_stats uffd_stats[nr_cpus];
+
+ uffd_test_ctx_init(UFFD_FEATURE_WP_UNPOPULATED);
+
+ if (posix_memalign(&area, page_size, page_size))
+ err("out of memory");
+ zeropage = area;
+ bzero(zeropage, page_size);
+
+ pthread_mutex_lock(&uffd_read_mutex);
+
+ pthread_attr_init(&attr);
+ pthread_attr_setstacksize(&attr, 16*1024*1024);
+
+ while (bounces--) {
+ printf("bounces: %d, mode:", bounces);
+ if (bounces & BOUNCE_RANDOM)
+ printf(" rnd");
+ if (bounces & BOUNCE_RACINGFAULTS)
+ printf(" racing");
+ if (bounces & BOUNCE_VERIFY)
+ printf(" ver");
+ if (bounces & BOUNCE_POLL)
+ printf(" poll");
+ else
+ printf(" read");
+ printf(", ");
+ fflush(stdout);
+
+ if (bounces & BOUNCE_POLL)
+ fcntl(uffd, F_SETFL, uffd_flags | O_NONBLOCK);
+ else
+ fcntl(uffd, F_SETFL, uffd_flags & ~O_NONBLOCK);
+
+ /* register */
+ uffdio_register.range.start = (unsigned long) area_dst;
+ uffdio_register.range.len = nr_pages * page_size;
+ uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
+ if (test_uffdio_wp)
+ uffdio_register.mode |= UFFDIO_REGISTER_MODE_WP;
+ if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register))
+ err("register failure");
+ assert_expected_ioctls_present(
+ uffdio_register.mode, uffdio_register.ioctls);
+
+ if (area_dst_alias) {
+ uffdio_register.range.start = (unsigned long)
+ area_dst_alias;
+ if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register))
+ err("register failure alias");
+ }
+
+ /*
+ * The madvise done previously isn't enough: some
+ * uffd_thread could have read userfaults (one of
+ * those already resolved by the background thread)
+ * and it may be in the process of calling
+ * UFFDIO_COPY. UFFDIO_COPY will read the zapped
+ * area_src and it would map a zero page in it (of
+ * course such a UFFDIO_COPY is perfectly safe as it'd
+ * return -EEXIST). The problem comes at the next
+ * bounce though: that racing UFFDIO_COPY would
+ * generate zeropages in the area_src, so invalidating
+ * the previous MADV_DONTNEED. Without this additional
+ * MADV_DONTNEED those zeropages leftovers in the
+ * area_src would lead to -EEXIST failure during the
+ * next bounce, effectively leaving a zeropage in the
+ * area_dst.
+ *
+ * Try to comment this out madvise to see the memory
+ * corruption being caught pretty quick.
+ *
+ * khugepaged is also inhibited to collapse THP after
+ * MADV_DONTNEED only after the UFFDIO_REGISTER, so it's
+ * required to MADV_DONTNEED here.
+ */
+ uffd_test_ops->release_pages(area_dst);
+
+ uffd_stats_reset(uffd_stats, nr_cpus);
+
+ /* bounce pass */
+ if (stress(uffd_stats))
+ return 1;
+
+ /* Clear all the write protections if there is any */
+ if (test_uffdio_wp)
+ wp_range(uffd, (unsigned long)area_dst,
+ nr_pages * page_size, false);
+
+ /* unregister */
+ if (ioctl(uffd, UFFDIO_UNREGISTER, &uffdio_register.range))
+ err("unregister failure");
+ if (area_dst_alias) {
+ uffdio_register.range.start = (unsigned long) area_dst;
+ if (ioctl(uffd, UFFDIO_UNREGISTER,
+ &uffdio_register.range))
+ err("unregister failure alias");
+ }
+
+ /* verification */
+ if (bounces & BOUNCE_VERIFY)
+ for (nr = 0; nr < nr_pages; nr++)
+ if (*area_count(area_dst, nr) != count_verify[nr])
+ err("error area_count %llu %llu %lu\n",
+ *area_count(area_src, nr),
+ count_verify[nr], nr);
+
+ /* prepare next bounce */
+ swap(area_src, area_dst);
+
+ swap(area_src_alias, area_dst_alias);
+
+ uffd_stats_report(uffd_stats, 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();
+}
+
+static void set_test_type(const char *type)
+{
+ if (!strcmp(type, "anon")) {
+ test_type = TEST_ANON;
+ uffd_test_ops = &anon_uffd_test_ops;
+ } else if (!strcmp(type, "hugetlb")) {
+ test_type = TEST_HUGETLB;
+ uffd_test_ops = &hugetlb_uffd_test_ops;
+ } else if (!strcmp(type, "hugetlb_shared")) {
+ map_shared = true;
+ test_type = TEST_HUGETLB;
+ uffd_test_ops = &hugetlb_uffd_test_ops;
+ /* Minor faults require shared hugetlb; only enable here. */
+ test_uffdio_minor = true;
+ } else if (!strcmp(type, "shmem")) {
+ map_shared = true;
+ test_type = TEST_SHMEM;
+ uffd_test_ops = &shmem_uffd_test_ops;
+ test_uffdio_minor = true;
+ }
+}
+
+static void parse_test_type_arg(const char *raw_type)
+{
+ char *buf = strdup(raw_type);
+ uint64_t features = UFFD_API_FEATURES;
+
+ while (buf) {
+ const char *token = strsep(&buf, ":");
+
+ if (!test_type)
+ set_test_type(token);
+ else if (!strcmp(token, "dev"))
+ test_dev_userfaultfd = true;
+ else if (!strcmp(token, "syscall"))
+ test_dev_userfaultfd = false;
+ else if (!strcmp(token, "collapse"))
+ test_collapse = true;
+ else
+ err("unrecognized test mod '%s'", token);
+ }
+
+ if (!test_type)
+ err("failed to parse test type argument: '%s'", raw_type);
+
+ if (test_collapse && test_type != TEST_SHMEM)
+ err("Unsupported test: %s", raw_type);
+
+ if (test_type == TEST_HUGETLB)
+ page_size = hpage_size;
+ else
+ page_size = sysconf(_SC_PAGE_SIZE);
+
+ if (!page_size)
+ err("Unable to determine page size");
+ if ((unsigned long) area_count(NULL, 0) + sizeof(unsigned long long) * 2
+ > page_size)
+ err("Impossible to run this test");
+
+ /*
+ * Whether we can test certain features depends not just on test type,
+ * but also on whether or not this particular kernel supports the
+ * feature.
+ */
+
+ userfaultfd_open(&features);
+
+ test_uffdio_wp = test_uffdio_wp &&
+ (features & UFFD_FEATURE_PAGEFAULT_FLAG_WP);
+ test_uffdio_minor = test_uffdio_minor &&
+ (features & uffd_minor_feature());
+
+ close(uffd);
+ uffd = -1;
+}
+
+static void sigalrm(int sig)
+{
+ if (sig != SIGALRM)
+ abort();
+ test_uffdio_copy_eexist = true;
+ alarm(ALARM_INTERVAL_SECS);
+}
+
+int main(int argc, char **argv)
+{
+ size_t bytes;
+
+ if (argc < 4)
+ usage();
+
+ if (signal(SIGALRM, sigalrm) == SIG_ERR)
+ err("failed to arm SIGALRM");
+ alarm(ALARM_INTERVAL_SECS);
+
+ hpage_size = default_huge_page_size();
+ parse_test_type_arg(argv[1]);
+ bytes = atol(argv[2]) * 1024 * 1024;
+
+ if (test_collapse && bytes & (hpage_size - 1))
+ err("MiB must be multiple of %lu if :collapse mod set",
+ hpage_size >> 20);
+
+ nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
+
+ if (test_collapse) {
+ /* nr_cpus must divide (bytes / page_size), otherwise,
+ * area allocations of (nr_pages * paze_size) won't be a
+ * multiple of hpage_size, even if bytes is a multiple of
+ * hpage_size.
+ *
+ * This means that nr_cpus must divide (N * (2 << (H-P))
+ * where:
+ * bytes = hpage_size * N
+ * hpage_size = 2 << H
+ * page_size = 2 << P
+ *
+ * And we want to chose nr_cpus to be the largest value
+ * satisfying this constraint, not larger than the number
+ * of online CPUs. Unfortunately, prime factorization of
+ * N and nr_cpus may be arbitrary, so have to search for it.
+ * Instead, just use the highest power of 2 dividing both
+ * nr_cpus and (bytes / page_size).
+ */
+ int x = factor_of_2(nr_cpus);
+ int y = factor_of_2(bytes / page_size);
+
+ nr_cpus = x < y ? x : y;
+ }
+ nr_pages_per_cpu = bytes / page_size / nr_cpus;
+ if (!nr_pages_per_cpu) {
+ _err("invalid MiB");
+ usage();
+ }
+
+ bounces = atoi(argv[3]);
+ if (bounces <= 0) {
+ _err("invalid bounces");
+ usage();
+ }
+ nr_pages = nr_pages_per_cpu * nr_cpus;
+
+ if (test_type == TEST_SHMEM || test_type == TEST_HUGETLB) {
+ unsigned int memfd_flags = 0;
+
+ if (test_type == TEST_HUGETLB)
+ memfd_flags = MFD_HUGETLB;
+ mem_fd = memfd_create(argv[0], memfd_flags);
+ if (mem_fd < 0)
+ err("memfd_create");
+ if (ftruncate(mem_fd, nr_pages * page_size * 2))
+ err("ftruncate");
+ if (fallocate(mem_fd,
+ FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, 0,
+ nr_pages * page_size * 2))
+ err("fallocate");
+ }
+ printf("nr_pages: %lu, nr_pages_per_cpu: %lu\n",
+ nr_pages, nr_pages_per_cpu);
+ return userfaultfd_stress();
+}
+
+#else /* __NR_userfaultfd */
+
+#warning "missing __NR_userfaultfd definition"
+
+int main(void)
+{
+ printf("skip: Skipping userfaultfd test (missing __NR_userfaultfd)\n");
+ return KSFT_SKIP;
+}
+
+#endif /* __NR_userfaultfd */
--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Userfaultfd unit tests.
+ *
+ * Copyright (C) 2015-2023 Red Hat, Inc.
+ */
+
+#include "uffd-common.h"
+
+#ifdef __NR_userfaultfd
+
+int main(int argc, char *argv[])
+{
+ return KSFT_PASS;
+}
+
+#else /* __NR_userfaultfd */
+
+#warning "missing __NR_userfaultfd definition"
+
+int main(void)
+{
+ printf("Skipping %s (missing __NR_userfaultfd)\n", __file__);
+ return KSFT_SKIP;
+}
+
+#endif /* __NR_userfaultfd */
+++ /dev/null
-// SPDX-License-Identifier: GPL-2.0-only
-/*
- * Stress userfaultfd syscall.
- *
- * Copyright (C) 2015 Red Hat, Inc.
- *
- * This test allocates two virtual areas and bounces the physical
- * memory across the two virtual areas (from area_src to area_dst)
- * using userfaultfd.
- *
- * There are three threads running per CPU:
- *
- * 1) one per-CPU thread takes a per-page pthread_mutex in a random
- * page of the area_dst (while the physical page may still be in
- * area_src), and increments a per-page counter in the same page,
- * and checks its value against a verification region.
- *
- * 2) another per-CPU thread handles the userfaults generated by
- * thread 1 above. userfaultfd blocking reads or poll() modes are
- * exercised interleaved.
- *
- * 3) one last per-CPU thread transfers the memory in the background
- * at maximum bandwidth (if not already transferred by thread
- * 2). Each cpu thread takes cares of transferring a portion of the
- * area.
- *
- * When all threads of type 3 completed the transfer, one bounce is
- * complete. area_src and area_dst are then swapped. All threads are
- * respawned and so the bounce is immediately restarted in the
- * opposite direction.
- *
- * per-CPU threads 1 by triggering userfaults inside
- * pthread_mutex_lock will also verify the atomicity of the memory
- * transfer (UFFDIO_COPY).
- */
-
-#include "uffd-common.h"
-
-#ifdef __NR_userfaultfd
-
-#define BOUNCE_RANDOM (1<<0)
-#define BOUNCE_RACINGFAULTS (1<<1)
-#define BOUNCE_VERIFY (1<<2)
-#define BOUNCE_POLL (1<<3)
-static int bounces;
-
-/* exercise the test_uffdio_*_eexist every ALARM_INTERVAL_SECS */
-#define ALARM_INTERVAL_SECS 10
-static char *zeropage;
-pthread_attr_t attr;
-
-#define swap(a, b) \
- do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0)
-
-#define factor_of_2(x) ((x) ^ ((x) & ((x) - 1)))
-
-const char *examples =
- "# Run anonymous memory test on 100MiB region with 99999 bounces:\n"
- "./userfaultfd anon 100 99999\n\n"
- "# Run the same anonymous memory test, but using /dev/userfaultfd:\n"
- "./userfaultfd anon:dev 100 99999\n\n"
- "# Run share memory test on 1GiB region with 99 bounces:\n"
- "./userfaultfd shmem 1000 99\n\n"
- "# Run hugetlb memory test on 256MiB region with 50 bounces:\n"
- "./userfaultfd hugetlb 256 50\n\n"
- "# Run the same hugetlb test but using shared file:\n"
- "./userfaultfd hugetlb_shared 256 50\n\n"
- "# 10MiB-~6GiB 999 bounces anonymous test, "
- "continue forever unless an error triggers\n"
- "while ./userfaultfd anon $[RANDOM % 6000 + 10] 999; do true; done\n\n";
-
-static void usage(void)
-{
- fprintf(stderr, "\nUsage: ./userfaultfd <test type> <MiB> <bounces> "
- "[hugetlbfs_file]\n\n");
- fprintf(stderr, "Supported <test type>: anon, hugetlb, "
- "hugetlb_shared, shmem\n\n");
- fprintf(stderr, "'Test mods' can be joined to the test type string with a ':'. "
- "Supported mods:\n");
- fprintf(stderr, "\tsyscall - Use userfaultfd(2) (default)\n");
- fprintf(stderr, "\tdev - Use /dev/userfaultfd instead of userfaultfd(2)\n");
- fprintf(stderr, "\tcollapse - Test MADV_COLLAPSE of UFFDIO_REGISTER_MODE_MINOR\n"
- "memory\n");
- fprintf(stderr, "\nExample test mod usage:\n");
- fprintf(stderr, "# Run anonymous memory test with /dev/userfaultfd:\n");
- fprintf(stderr, "./userfaultfd anon:dev 100 99999\n\n");
-
- fprintf(stderr, "Examples:\n\n");
- fprintf(stderr, "%s", examples);
- exit(1);
-}
-
-static void uffd_stats_reset(struct uffd_stats *uffd_stats,
- unsigned long n_cpus)
-{
- int i;
-
- for (i = 0; i < n_cpus; i++) {
- uffd_stats[i].cpu = i;
- uffd_stats[i].missing_faults = 0;
- uffd_stats[i].wp_faults = 0;
- uffd_stats[i].minor_faults = 0;
- }
-}
-
-static inline uint64_t uffd_minor_feature(void)
-{
- if (test_type == TEST_HUGETLB && map_shared)
- return UFFD_FEATURE_MINOR_HUGETLBFS;
- else if (test_type == TEST_SHMEM)
- return UFFD_FEATURE_MINOR_SHMEM;
- else
- return 0;
-}
-
-static int my_bcmp(char *str1, char *str2, size_t n)
-{
- unsigned long i;
- for (i = 0; i < n; i++)
- if (str1[i] != str2[i])
- return 1;
- return 0;
-}
-
-static void *locking_thread(void *arg)
-{
- unsigned long cpu = (unsigned long) arg;
- unsigned long page_nr;
- unsigned long long count;
-
- if (!(bounces & BOUNCE_RANDOM)) {
- page_nr = -bounces;
- if (!(bounces & BOUNCE_RACINGFAULTS))
- page_nr += cpu * nr_pages_per_cpu;
- }
-
- while (!finished) {
- if (bounces & BOUNCE_RANDOM) {
- if (getrandom(&page_nr, sizeof(page_nr), 0) != sizeof(page_nr))
- err("getrandom failed");
- } else
- page_nr += 1;
- page_nr %= nr_pages;
- pthread_mutex_lock(area_mutex(area_dst, page_nr));
- count = *area_count(area_dst, page_nr);
- if (count != count_verify[page_nr])
- err("page_nr %lu memory corruption %llu %llu",
- page_nr, count, count_verify[page_nr]);
- count++;
- *area_count(area_dst, page_nr) = count_verify[page_nr] = count;
- pthread_mutex_unlock(area_mutex(area_dst, page_nr));
- }
-
- return NULL;
-}
-
-static int copy_page_retry(int ufd, unsigned long offset)
-{
- return __copy_page(ufd, offset, true);
-}
-
-pthread_mutex_t uffd_read_mutex = PTHREAD_MUTEX_INITIALIZER;
-
-static void *uffd_read_thread(void *arg)
-{
- struct uffd_stats *stats = (struct uffd_stats *)arg;
- struct uffd_msg msg;
-
- pthread_mutex_unlock(&uffd_read_mutex);
- /* from here cancellation is ok */
-
- for (;;) {
- if (uffd_read_msg(uffd, &msg))
- continue;
- uffd_handle_page_fault(&msg, stats);
- }
-
- return NULL;
-}
-
-static void *background_thread(void *arg)
-{
- unsigned long cpu = (unsigned long) arg;
- unsigned long page_nr, start_nr, mid_nr, end_nr;
-
- start_nr = cpu * nr_pages_per_cpu;
- end_nr = (cpu+1) * nr_pages_per_cpu;
- mid_nr = (start_nr + end_nr) / 2;
-
- /* Copy the first half of the pages */
- for (page_nr = start_nr; page_nr < mid_nr; page_nr++)
- copy_page_retry(uffd, page_nr * page_size);
-
- /*
- * If we need to test uffd-wp, set it up now. Then we'll have
- * at least the first half of the pages mapped already which
- * can be write-protected for testing
- */
- if (test_uffdio_wp)
- wp_range(uffd, (unsigned long)area_dst + start_nr * page_size,
- nr_pages_per_cpu * page_size, true);
-
- /*
- * Continue the 2nd half of the page copying, handling write
- * protection faults if any
- */
- for (page_nr = mid_nr; page_nr < end_nr; page_nr++)
- copy_page_retry(uffd, page_nr * page_size);
-
- return NULL;
-}
-
-static int stress(struct uffd_stats *uffd_stats)
-{
- unsigned long cpu;
- pthread_t locking_threads[nr_cpus];
- pthread_t uffd_threads[nr_cpus];
- pthread_t background_threads[nr_cpus];
-
- finished = 0;
- for (cpu = 0; cpu < nr_cpus; cpu++) {
- if (pthread_create(&locking_threads[cpu], &attr,
- locking_thread, (void *)cpu))
- return 1;
- if (bounces & BOUNCE_POLL) {
- if (pthread_create(&uffd_threads[cpu], &attr,
- uffd_poll_thread,
- (void *)&uffd_stats[cpu]))
- return 1;
- } else {
- if (pthread_create(&uffd_threads[cpu], &attr,
- uffd_read_thread,
- (void *)&uffd_stats[cpu]))
- return 1;
- pthread_mutex_lock(&uffd_read_mutex);
- }
- if (pthread_create(&background_threads[cpu], &attr,
- background_thread, (void *)cpu))
- return 1;
- }
- for (cpu = 0; cpu < nr_cpus; cpu++)
- if (pthread_join(background_threads[cpu], NULL))
- return 1;
-
- /*
- * Be strict and immediately zap area_src, the whole area has
- * been transferred already by the background treads. The
- * area_src could then be faulted in a racy way by still
- * running uffdio_threads reading zeropages after we zapped
- * area_src (but they're guaranteed to get -EEXIST from
- * UFFDIO_COPY without writing zero pages into area_dst
- * because the background threads already completed).
- */
- uffd_test_ops->release_pages(area_src);
-
- finished = 1;
- for (cpu = 0; cpu < nr_cpus; cpu++)
- if (pthread_join(locking_threads[cpu], NULL))
- return 1;
-
- for (cpu = 0; cpu < nr_cpus; cpu++) {
- char c;
- if (bounces & BOUNCE_POLL) {
- if (write(pipefd[cpu*2+1], &c, 1) != 1)
- err("pipefd write error");
- if (pthread_join(uffd_threads[cpu],
- (void *)&uffd_stats[cpu]))
- return 1;
- } else {
- if (pthread_cancel(uffd_threads[cpu]))
- return 1;
- if (pthread_join(uffd_threads[cpu], NULL))
- return 1;
- }
- }
-
- return 0;
-}
-
-sigjmp_buf jbuf, *sigbuf;
-
-static void sighndl(int sig, siginfo_t *siginfo, void *ptr)
-{
- if (sig == SIGBUS) {
- if (sigbuf)
- siglongjmp(*sigbuf, 1);
- abort();
- }
-}
-
-/*
- * For non-cooperative userfaultfd test we fork() a process that will
- * generate pagefaults, will mremap the area monitored by the
- * userfaultfd and at last this process will release the monitored
- * area.
- * For the anonymous and shared memory the area is divided into two
- * parts, the first part is accessed before mremap, and the second
- * part is accessed after mremap. Since hugetlbfs does not support
- * mremap, the entire monitored area is accessed in a single pass for
- * HUGETLB_TEST.
- * The release of the pages currently generates event for shmem and
- * anonymous memory (UFFD_EVENT_REMOVE), hence it is not checked
- * for hugetlb.
- * For signal test(UFFD_FEATURE_SIGBUS), signal_test = 1, we register
- * monitored area, generate pagefaults and test that signal is delivered.
- * Use UFFDIO_COPY to allocate missing page and retry. For signal_test = 2
- * test robustness use case - we release monitored area, fork a process
- * that will generate pagefaults and verify signal is generated.
- * This also tests UFFD_FEATURE_EVENT_FORK event along with the signal
- * feature. Using monitor thread, verify no userfault events are generated.
- */
-static int faulting_process(int signal_test)
-{
- unsigned long nr;
- unsigned long long count;
- unsigned long split_nr_pages;
- unsigned long lastnr;
- struct sigaction act;
- volatile unsigned long signalled = 0;
-
- split_nr_pages = (nr_pages + 1) / 2;
-
- if (signal_test) {
- sigbuf = &jbuf;
- memset(&act, 0, sizeof(act));
- act.sa_sigaction = sighndl;
- act.sa_flags = SA_SIGINFO;
- if (sigaction(SIGBUS, &act, 0))
- err("sigaction");
- lastnr = (unsigned long)-1;
- }
-
- for (nr = 0; nr < split_nr_pages; nr++) {
- volatile int steps = 1;
- unsigned long offset = nr * page_size;
-
- if (signal_test) {
- if (sigsetjmp(*sigbuf, 1) != 0) {
- if (steps == 1 && nr == lastnr)
- err("Signal repeated");
-
- lastnr = nr;
- if (signal_test == 1) {
- if (steps == 1) {
- /* This is a MISSING request */
- steps++;
- if (copy_page(uffd, offset))
- signalled++;
- } else {
- /* This is a WP request */
- assert(steps == 2);
- wp_range(uffd,
- (__u64)area_dst +
- offset,
- page_size, false);
- }
- } else {
- signalled++;
- continue;
- }
- }
- }
-
- count = *area_count(area_dst, nr);
- if (count != count_verify[nr])
- err("nr %lu memory corruption %llu %llu\n",
- nr, count, count_verify[nr]);
- /*
- * Trigger write protection if there is by writing
- * the same value back.
- */
- *area_count(area_dst, nr) = count;
- }
-
- if (signal_test)
- return signalled != split_nr_pages;
-
- area_dst = mremap(area_dst, nr_pages * page_size, nr_pages * page_size,
- MREMAP_MAYMOVE | MREMAP_FIXED, area_src);
- if (area_dst == MAP_FAILED)
- err("mremap");
- /* Reset area_src since we just clobbered it */
- area_src = NULL;
-
- for (; nr < nr_pages; nr++) {
- count = *area_count(area_dst, nr);
- if (count != count_verify[nr]) {
- err("nr %lu memory corruption %llu %llu\n",
- nr, count, count_verify[nr]);
- }
- /*
- * Trigger write protection if there is by writing
- * the same value back.
- */
- *area_count(area_dst, nr) = count;
- }
-
- uffd_test_ops->release_pages(area_dst);
-
- for (nr = 0; nr < nr_pages; nr++)
- if (my_bcmp(area_dst + nr * page_size, zeropage, page_size))
- err("nr %lu is not zero", nr);
-
- return 0;
-}
-
-static void retry_uffdio_zeropage(int ufd,
- struct uffdio_zeropage *uffdio_zeropage,
- unsigned long offset)
-{
- uffd_test_ops->alias_mapping(&uffdio_zeropage->range.start,
- uffdio_zeropage->range.len,
- offset);
- if (ioctl(ufd, UFFDIO_ZEROPAGE, uffdio_zeropage)) {
- if (uffdio_zeropage->zeropage != -EEXIST)
- err("UFFDIO_ZEROPAGE error: %"PRId64,
- (int64_t)uffdio_zeropage->zeropage);
- } else {
- err("UFFDIO_ZEROPAGE error: %"PRId64,
- (int64_t)uffdio_zeropage->zeropage);
- }
-}
-
-static int __uffdio_zeropage(int ufd, unsigned long offset)
-{
- struct uffdio_zeropage uffdio_zeropage;
- int ret;
- bool has_zeropage = !(test_type == TEST_HUGETLB);
- __s64 res;
-
- if (offset >= nr_pages * page_size)
- err("unexpected offset %lu", offset);
- uffdio_zeropage.range.start = (unsigned long) area_dst + offset;
- uffdio_zeropage.range.len = page_size;
- uffdio_zeropage.mode = 0;
- ret = ioctl(ufd, UFFDIO_ZEROPAGE, &uffdio_zeropage);
- res = uffdio_zeropage.zeropage;
- if (ret) {
- /* real retval in ufdio_zeropage.zeropage */
- if (has_zeropage)
- err("UFFDIO_ZEROPAGE error: %"PRId64, (int64_t)res);
- else if (res != -EINVAL)
- err("UFFDIO_ZEROPAGE not -EINVAL");
- } else if (has_zeropage) {
- if (res != page_size) {
- err("UFFDIO_ZEROPAGE unexpected size");
- } else {
- retry_uffdio_zeropage(ufd, &uffdio_zeropage,
- offset);
- return 1;
- }
- } else
- err("UFFDIO_ZEROPAGE succeeded");
-
- return 0;
-}
-
-static int uffdio_zeropage(int ufd, unsigned long offset)
-{
- return __uffdio_zeropage(ufd, offset);
-}
-
-/* exercise UFFDIO_ZEROPAGE */
-static int userfaultfd_zeropage_test(void)
-{
- struct uffdio_register uffdio_register;
-
- printf("testing UFFDIO_ZEROPAGE: ");
- fflush(stdout);
-
- uffd_test_ctx_init(0);
-
- uffdio_register.range.start = (unsigned long) area_dst;
- uffdio_register.range.len = nr_pages * page_size;
- uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
- if (test_uffdio_wp)
- uffdio_register.mode |= UFFDIO_REGISTER_MODE_WP;
- if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register))
- err("register failure");
-
- assert_expected_ioctls_present(
- uffdio_register.mode, uffdio_register.ioctls);
-
- if (area_dst_alias) {
- /* Needed this to test zeropage-retry on shared memory */
- uffdio_register.range.start = (unsigned long) area_dst_alias;
- if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register))
- err("register failure");
- }
-
- if (uffdio_zeropage(uffd, 0))
- if (my_bcmp(area_dst, zeropage, page_size))
- err("zeropage is not zero");
-
- printf("done.\n");
- return 0;
-}
-
-static int userfaultfd_events_test(void)
-{
- struct uffdio_register uffdio_register;
- pthread_t uffd_mon;
- int err, features;
- pid_t pid;
- char c;
- struct uffd_stats stats = { 0 };
-
- printf("testing events (fork, remap, remove): ");
- fflush(stdout);
-
- features = UFFD_FEATURE_EVENT_FORK | UFFD_FEATURE_EVENT_REMAP |
- UFFD_FEATURE_EVENT_REMOVE;
- uffd_test_ctx_init(features);
-
- fcntl(uffd, F_SETFL, uffd_flags | O_NONBLOCK);
-
- uffdio_register.range.start = (unsigned long) area_dst;
- uffdio_register.range.len = nr_pages * page_size;
- uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
- if (test_uffdio_wp)
- uffdio_register.mode |= UFFDIO_REGISTER_MODE_WP;
- if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register))
- err("register failure");
-
- assert_expected_ioctls_present(
- uffdio_register.mode, uffdio_register.ioctls);
-
- if (pthread_create(&uffd_mon, &attr, uffd_poll_thread, &stats))
- err("uffd_poll_thread create");
-
- pid = fork();
- if (pid < 0)
- err("fork");
-
- if (!pid)
- exit(faulting_process(0));
-
- waitpid(pid, &err, 0);
- if (err)
- err("faulting process failed");
- if (write(pipefd[1], &c, sizeof(c)) != sizeof(c))
- err("pipe write");
- if (pthread_join(uffd_mon, NULL))
- return 1;
-
- uffd_stats_report(&stats, 1);
-
- return stats.missing_faults != nr_pages;
-}
-
-static int userfaultfd_sig_test(void)
-{
- struct uffdio_register uffdio_register;
- unsigned long userfaults;
- pthread_t uffd_mon;
- int err, features;
- pid_t pid;
- char c;
- struct uffd_stats stats = { 0 };
-
- printf("testing signal delivery: ");
- fflush(stdout);
-
- features = UFFD_FEATURE_EVENT_FORK|UFFD_FEATURE_SIGBUS;
- uffd_test_ctx_init(features);
-
- fcntl(uffd, F_SETFL, uffd_flags | O_NONBLOCK);
-
- uffdio_register.range.start = (unsigned long) area_dst;
- uffdio_register.range.len = nr_pages * page_size;
- uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
- if (test_uffdio_wp)
- uffdio_register.mode |= UFFDIO_REGISTER_MODE_WP;
- if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register))
- err("register failure");
-
- assert_expected_ioctls_present(
- uffdio_register.mode, uffdio_register.ioctls);
-
- if (faulting_process(1))
- err("faulting process failed");
-
- uffd_test_ops->release_pages(area_dst);
-
- if (pthread_create(&uffd_mon, &attr, uffd_poll_thread, &stats))
- err("uffd_poll_thread create");
-
- pid = fork();
- if (pid < 0)
- err("fork");
-
- if (!pid)
- exit(faulting_process(2));
-
- waitpid(pid, &err, 0);
- if (err)
- err("faulting process failed");
- if (write(pipefd[1], &c, sizeof(c)) != sizeof(c))
- err("pipe write");
- if (pthread_join(uffd_mon, (void **)&userfaults))
- return 1;
-
- printf("done.\n");
- if (userfaults)
- err("Signal test failed, userfaults: %ld", userfaults);
-
- return userfaults != 0;
-}
-
-void check_memory_contents(char *p)
-{
- unsigned long i;
- uint8_t expected_byte;
- void *expected_page;
-
- if (posix_memalign(&expected_page, page_size, page_size))
- err("out of memory");
-
- for (i = 0; i < nr_pages; ++i) {
- expected_byte = ~((uint8_t)(i % ((uint8_t)-1)));
- memset(expected_page, expected_byte, page_size);
- if (my_bcmp(expected_page, p + (i * page_size), page_size))
- err("unexpected page contents after minor fault");
- }
-
- free(expected_page);
-}
-
-static int userfaultfd_minor_test(void)
-{
- unsigned long p;
- struct uffdio_register uffdio_register;
- pthread_t uffd_mon;
- char c;
- struct uffd_stats stats = { 0 };
-
- if (!test_uffdio_minor)
- return 0;
-
- printf("testing minor faults: ");
- fflush(stdout);
-
- uffd_test_ctx_init(uffd_minor_feature());
-
- uffdio_register.range.start = (unsigned long)area_dst_alias;
- uffdio_register.range.len = nr_pages * page_size;
- uffdio_register.mode = UFFDIO_REGISTER_MODE_MINOR;
- if (test_uffdio_wp)
- uffdio_register.mode |= UFFDIO_REGISTER_MODE_WP;
- if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register))
- err("register failure");
-
- assert_expected_ioctls_present(
- uffdio_register.mode, uffdio_register.ioctls);
-
- /*
- * After registering with UFFD, populate the non-UFFD-registered side of
- * the shared mapping. This should *not* trigger any UFFD minor faults.
- */
- for (p = 0; p < nr_pages; ++p) {
- memset(area_dst + (p * page_size), p % ((uint8_t)-1),
- page_size);
- }
-
- if (pthread_create(&uffd_mon, &attr, uffd_poll_thread, &stats))
- err("uffd_poll_thread create");
-
- /*
- * Read each of the pages back using the UFFD-registered mapping. We
- * expect that the first time we touch a page, it will result in a minor
- * fault. uffd_poll_thread will resolve the fault by bit-flipping the
- * page's contents, and then issuing a CONTINUE ioctl.
- */
- check_memory_contents(area_dst_alias);
-
- if (write(pipefd[1], &c, sizeof(c)) != sizeof(c))
- err("pipe write");
- if (pthread_join(uffd_mon, NULL))
- return 1;
-
- uffd_stats_report(&stats, 1);
-
- if (test_collapse) {
- printf("testing collapse of uffd memory into PMD-mapped THPs:");
- if (madvise(area_dst_alias, nr_pages * page_size,
- MADV_COLLAPSE))
- err("madvise(MADV_COLLAPSE)");
-
- uffd_test_ops->check_pmd_mapping(area_dst,
- nr_pages * page_size /
- hpage_size);
- /*
- * This won't cause uffd-fault - it purely just makes sure there
- * was no corruption.
- */
- check_memory_contents(area_dst_alias);
- printf(" done.\n");
- }
-
- return stats.missing_faults != 0 || stats.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)
-{
- struct uffdio_register uffdio_register;
- 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");
- }
-
- uffdio_register.range.start = (unsigned long) area_dst;
- uffdio_register.range.len = nr_pages * page_size;
- uffdio_register.mode = UFFDIO_REGISTER_MODE_WP;
- if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register))
- 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;
- unsigned long nr;
- struct uffdio_register uffdio_register;
- struct uffd_stats uffd_stats[nr_cpus];
-
- uffd_test_ctx_init(UFFD_FEATURE_WP_UNPOPULATED);
-
- if (posix_memalign(&area, page_size, page_size))
- err("out of memory");
- zeropage = area;
- bzero(zeropage, page_size);
-
- pthread_mutex_lock(&uffd_read_mutex);
-
- pthread_attr_init(&attr);
- pthread_attr_setstacksize(&attr, 16*1024*1024);
-
- while (bounces--) {
- printf("bounces: %d, mode:", bounces);
- if (bounces & BOUNCE_RANDOM)
- printf(" rnd");
- if (bounces & BOUNCE_RACINGFAULTS)
- printf(" racing");
- if (bounces & BOUNCE_VERIFY)
- printf(" ver");
- if (bounces & BOUNCE_POLL)
- printf(" poll");
- else
- printf(" read");
- printf(", ");
- fflush(stdout);
-
- if (bounces & BOUNCE_POLL)
- fcntl(uffd, F_SETFL, uffd_flags | O_NONBLOCK);
- else
- fcntl(uffd, F_SETFL, uffd_flags & ~O_NONBLOCK);
-
- /* register */
- uffdio_register.range.start = (unsigned long) area_dst;
- uffdio_register.range.len = nr_pages * page_size;
- uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
- if (test_uffdio_wp)
- uffdio_register.mode |= UFFDIO_REGISTER_MODE_WP;
- if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register))
- err("register failure");
- assert_expected_ioctls_present(
- uffdio_register.mode, uffdio_register.ioctls);
-
- if (area_dst_alias) {
- uffdio_register.range.start = (unsigned long)
- area_dst_alias;
- if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register))
- err("register failure alias");
- }
-
- /*
- * The madvise done previously isn't enough: some
- * uffd_thread could have read userfaults (one of
- * those already resolved by the background thread)
- * and it may be in the process of calling
- * UFFDIO_COPY. UFFDIO_COPY will read the zapped
- * area_src and it would map a zero page in it (of
- * course such a UFFDIO_COPY is perfectly safe as it'd
- * return -EEXIST). The problem comes at the next
- * bounce though: that racing UFFDIO_COPY would
- * generate zeropages in the area_src, so invalidating
- * the previous MADV_DONTNEED. Without this additional
- * MADV_DONTNEED those zeropages leftovers in the
- * area_src would lead to -EEXIST failure during the
- * next bounce, effectively leaving a zeropage in the
- * area_dst.
- *
- * Try to comment this out madvise to see the memory
- * corruption being caught pretty quick.
- *
- * khugepaged is also inhibited to collapse THP after
- * MADV_DONTNEED only after the UFFDIO_REGISTER, so it's
- * required to MADV_DONTNEED here.
- */
- uffd_test_ops->release_pages(area_dst);
-
- uffd_stats_reset(uffd_stats, nr_cpus);
-
- /* bounce pass */
- if (stress(uffd_stats))
- return 1;
-
- /* Clear all the write protections if there is any */
- if (test_uffdio_wp)
- wp_range(uffd, (unsigned long)area_dst,
- nr_pages * page_size, false);
-
- /* unregister */
- if (ioctl(uffd, UFFDIO_UNREGISTER, &uffdio_register.range))
- err("unregister failure");
- if (area_dst_alias) {
- uffdio_register.range.start = (unsigned long) area_dst;
- if (ioctl(uffd, UFFDIO_UNREGISTER,
- &uffdio_register.range))
- err("unregister failure alias");
- }
-
- /* verification */
- if (bounces & BOUNCE_VERIFY)
- for (nr = 0; nr < nr_pages; nr++)
- if (*area_count(area_dst, nr) != count_verify[nr])
- err("error area_count %llu %llu %lu\n",
- *area_count(area_src, nr),
- count_verify[nr], nr);
-
- /* prepare next bounce */
- swap(area_src, area_dst);
-
- swap(area_src_alias, area_dst_alias);
-
- uffd_stats_report(uffd_stats, 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();
-}
-
-static void set_test_type(const char *type)
-{
- if (!strcmp(type, "anon")) {
- test_type = TEST_ANON;
- uffd_test_ops = &anon_uffd_test_ops;
- } else if (!strcmp(type, "hugetlb")) {
- test_type = TEST_HUGETLB;
- uffd_test_ops = &hugetlb_uffd_test_ops;
- } else if (!strcmp(type, "hugetlb_shared")) {
- map_shared = true;
- test_type = TEST_HUGETLB;
- uffd_test_ops = &hugetlb_uffd_test_ops;
- /* Minor faults require shared hugetlb; only enable here. */
- test_uffdio_minor = true;
- } else if (!strcmp(type, "shmem")) {
- map_shared = true;
- test_type = TEST_SHMEM;
- uffd_test_ops = &shmem_uffd_test_ops;
- test_uffdio_minor = true;
- }
-}
-
-static void parse_test_type_arg(const char *raw_type)
-{
- char *buf = strdup(raw_type);
- uint64_t features = UFFD_API_FEATURES;
-
- while (buf) {
- const char *token = strsep(&buf, ":");
-
- if (!test_type)
- set_test_type(token);
- else if (!strcmp(token, "dev"))
- test_dev_userfaultfd = true;
- else if (!strcmp(token, "syscall"))
- test_dev_userfaultfd = false;
- else if (!strcmp(token, "collapse"))
- test_collapse = true;
- else
- err("unrecognized test mod '%s'", token);
- }
-
- if (!test_type)
- err("failed to parse test type argument: '%s'", raw_type);
-
- if (test_collapse && test_type != TEST_SHMEM)
- err("Unsupported test: %s", raw_type);
-
- if (test_type == TEST_HUGETLB)
- page_size = hpage_size;
- else
- page_size = sysconf(_SC_PAGE_SIZE);
-
- if (!page_size)
- err("Unable to determine page size");
- if ((unsigned long) area_count(NULL, 0) + sizeof(unsigned long long) * 2
- > page_size)
- err("Impossible to run this test");
-
- /*
- * Whether we can test certain features depends not just on test type,
- * but also on whether or not this particular kernel supports the
- * feature.
- */
-
- userfaultfd_open(&features);
-
- test_uffdio_wp = test_uffdio_wp &&
- (features & UFFD_FEATURE_PAGEFAULT_FLAG_WP);
- test_uffdio_minor = test_uffdio_minor &&
- (features & uffd_minor_feature());
-
- close(uffd);
- uffd = -1;
-}
-
-static void sigalrm(int sig)
-{
- if (sig != SIGALRM)
- abort();
- test_uffdio_copy_eexist = true;
- alarm(ALARM_INTERVAL_SECS);
-}
-
-int main(int argc, char **argv)
-{
- size_t bytes;
-
- if (argc < 4)
- usage();
-
- if (signal(SIGALRM, sigalrm) == SIG_ERR)
- err("failed to arm SIGALRM");
- alarm(ALARM_INTERVAL_SECS);
-
- hpage_size = default_huge_page_size();
- parse_test_type_arg(argv[1]);
- bytes = atol(argv[2]) * 1024 * 1024;
-
- if (test_collapse && bytes & (hpage_size - 1))
- err("MiB must be multiple of %lu if :collapse mod set",
- hpage_size >> 20);
-
- nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
-
- if (test_collapse) {
- /* nr_cpus must divide (bytes / page_size), otherwise,
- * area allocations of (nr_pages * paze_size) won't be a
- * multiple of hpage_size, even if bytes is a multiple of
- * hpage_size.
- *
- * This means that nr_cpus must divide (N * (2 << (H-P))
- * where:
- * bytes = hpage_size * N
- * hpage_size = 2 << H
- * page_size = 2 << P
- *
- * And we want to chose nr_cpus to be the largest value
- * satisfying this constraint, not larger than the number
- * of online CPUs. Unfortunately, prime factorization of
- * N and nr_cpus may be arbitrary, so have to search for it.
- * Instead, just use the highest power of 2 dividing both
- * nr_cpus and (bytes / page_size).
- */
- int x = factor_of_2(nr_cpus);
- int y = factor_of_2(bytes / page_size);
-
- nr_cpus = x < y ? x : y;
- }
- nr_pages_per_cpu = bytes / page_size / nr_cpus;
- if (!nr_pages_per_cpu) {
- _err("invalid MiB");
- usage();
- }
-
- bounces = atoi(argv[3]);
- if (bounces <= 0) {
- _err("invalid bounces");
- usage();
- }
- nr_pages = nr_pages_per_cpu * nr_cpus;
-
- if (test_type == TEST_SHMEM || test_type == TEST_HUGETLB) {
- unsigned int memfd_flags = 0;
-
- if (test_type == TEST_HUGETLB)
- memfd_flags = MFD_HUGETLB;
- mem_fd = memfd_create(argv[0], memfd_flags);
- if (mem_fd < 0)
- err("memfd_create");
- if (ftruncate(mem_fd, nr_pages * page_size * 2))
- err("ftruncate");
- if (fallocate(mem_fd,
- FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, 0,
- nr_pages * page_size * 2))
- err("fallocate");
- }
- printf("nr_pages: %lu, nr_pages_per_cpu: %lu\n",
- nr_pages, nr_pages_per_cpu);
- return userfaultfd_stress();
-}
-
-#else /* __NR_userfaultfd */
-
-#warning "missing __NR_userfaultfd definition"
-
-int main(void)
-{
- printf("skip: Skipping userfaultfd test (missing __NR_userfaultfd)\n");
- return KSFT_SKIP;
-}
-
-#endif /* __NR_userfaultfd */
projects / linux.git / commitdiff