diff options
Diffstat (limited to 'tools/testing/selftests/vm/userfaultfd.c')
| -rw-r--r-- | tools/testing/selftests/vm/userfaultfd.c | 1559 |
1 files changed, 1559 insertions, 0 deletions
diff --git a/tools/testing/selftests/vm/userfaultfd.c b/tools/testing/selftests/vm/userfaultfd.c new file mode 100644 index 000000000..034245ea3 --- /dev/null +++ b/tools/testing/selftests/vm/userfaultfd.c @@ -0,0 +1,1559 @@ +// 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). + */ + +#define _GNU_SOURCE +#include <stdio.h> +#include <errno.h> +#include <unistd.h> +#include <stdlib.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <fcntl.h> +#include <time.h> +#include <signal.h> +#include <poll.h> +#include <string.h> +#include <linux/mman.h> +#include <sys/mman.h> +#include <sys/syscall.h> +#include <sys/ioctl.h> +#include <sys/wait.h> +#include <pthread.h> +#include <linux/userfaultfd.h> +#include <setjmp.h> +#include <stdbool.h> +#include <assert.h> + +#include "../kselftest.h" + +#ifdef __NR_userfaultfd + +static unsigned long nr_cpus, nr_pages, nr_pages_per_cpu, page_size; + +#define BOUNCE_RANDOM (1<<0) +#define BOUNCE_RACINGFAULTS (1<<1) +#define BOUNCE_VERIFY (1<<2) +#define BOUNCE_POLL (1<<3) +static int bounces; + +#define TEST_ANON 1 +#define TEST_HUGETLB 2 +#define TEST_SHMEM 3 +static int test_type; + +/* exercise the test_uffdio_*_eexist every ALARM_INTERVAL_SECS */ +#define ALARM_INTERVAL_SECS 10 +static volatile bool test_uffdio_copy_eexist = true; +static volatile bool test_uffdio_zeropage_eexist = true; +/* Whether to test uffd write-protection */ +static bool test_uffdio_wp = false; + +static bool map_shared; +static int huge_fd; +static char *huge_fd_off0; +static unsigned long long *count_verify; +static int uffd, uffd_flags, finished, *pipefd; +static char *area_src, *area_src_alias, *area_dst, *area_dst_alias; +static char *zeropage; +pthread_attr_t attr; + +/* Userfaultfd test statistics */ +struct uffd_stats { + int cpu; + unsigned long missing_faults; + unsigned long wp_faults; +}; + +/* pthread_mutex_t starts at page offset 0 */ +#define area_mutex(___area, ___nr) \ + ((pthread_mutex_t *) ((___area) + (___nr)*page_size)) +/* + * count is placed in the page after pthread_mutex_t naturally aligned + * to avoid non alignment faults on non-x86 archs. + */ +#define area_count(___area, ___nr) \ + ((volatile unsigned long long *) ((unsigned long) \ + ((___area) + (___nr)*page_size + \ + sizeof(pthread_mutex_t) + \ + sizeof(unsigned long long) - 1) & \ + ~(unsigned long)(sizeof(unsigned long long) \ + - 1))) + +const char *examples = + "# Run anonymous memory test on 100MiB region with 99999 bounces:\n" + "./userfaultfd anon 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 (using /dev/hugepages/hugefile):\n" + "./userfaultfd hugetlb 256 50 /dev/hugepages/hugefile\n\n" + "# Run the same hugetlb test but using shmem:\n" + "./userfaultfd hugetlb_shared 256 50 /dev/hugepages/hugefile\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, "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; + } +} + +static void uffd_stats_report(struct uffd_stats *stats, int n_cpus) +{ + int i; + unsigned long long miss_total = 0, wp_total = 0; + + for (i = 0; i < n_cpus; i++) { + miss_total += stats[i].missing_faults; + wp_total += stats[i].wp_faults; + } + + printf("userfaults: %llu missing (", miss_total); + for (i = 0; i < n_cpus; i++) + printf("%lu+", stats[i].missing_faults); + printf("\b), %llu wp (", wp_total); + for (i = 0; i < n_cpus; i++) + printf("%lu+", stats[i].wp_faults); + printf("\b)\n"); +} + +static int anon_release_pages(char *rel_area) +{ + int ret = 0; + + if (madvise(rel_area, nr_pages * page_size, MADV_DONTNEED)) { + perror("madvise"); + ret = 1; + } + + return ret; +} + +static void anon_allocate_area(void **alloc_area) +{ + *alloc_area = mmap(NULL, nr_pages * page_size, PROT_READ | PROT_WRITE, + MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); + if (*alloc_area == MAP_FAILED) { + fprintf(stderr, "mmap of anonymous memory failed"); + *alloc_area = NULL; + } +} + +static void noop_alias_mapping(__u64 *start, size_t len, unsigned long offset) +{ +} + +/* HugeTLB memory */ +static int hugetlb_release_pages(char *rel_area) +{ + int ret = 0; + + if (fallocate(huge_fd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, + rel_area == huge_fd_off0 ? 0 : + nr_pages * page_size, + nr_pages * page_size)) { + perror("fallocate"); + ret = 1; + } + + return ret; +} + +static void hugetlb_allocate_area(void **alloc_area) +{ + void *area_alias = NULL; + char **alloc_area_alias; + + *alloc_area = mmap(NULL, nr_pages * page_size, PROT_READ | PROT_WRITE, + (map_shared ? MAP_SHARED : MAP_PRIVATE) | + MAP_HUGETLB, + huge_fd, *alloc_area == area_src ? 0 : + nr_pages * page_size); + if (*alloc_area == MAP_FAILED) { + perror("mmap of hugetlbfs file failed"); + goto fail; + } + + if (map_shared) { + area_alias = mmap(NULL, nr_pages * page_size, PROT_READ | PROT_WRITE, + MAP_SHARED | MAP_HUGETLB, + huge_fd, *alloc_area == area_src ? 0 : + nr_pages * page_size); + if (area_alias == MAP_FAILED) { + perror("mmap of hugetlb file alias failed"); + goto fail_munmap; + } + } + + if (*alloc_area == area_src) { + huge_fd_off0 = *alloc_area; + alloc_area_alias = &area_src_alias; + } else { + alloc_area_alias = &area_dst_alias; + } + if (area_alias) + *alloc_area_alias = area_alias; + + return; + +fail_munmap: + if (munmap(*alloc_area, nr_pages * page_size) < 0) { + perror("hugetlb munmap"); + exit(1); + } +fail: + *alloc_area = NULL; +} + +static void hugetlb_alias_mapping(__u64 *start, size_t len, unsigned long offset) +{ + if (!map_shared) + return; + /* + * We can't zap just the pagetable with hugetlbfs because + * MADV_DONTEED won't work. So exercise -EEXIST on a alias + * mapping where the pagetables are not established initially, + * this way we'll exercise the -EEXEC at the fs level. + */ + *start = (unsigned long) area_dst_alias + offset; +} + +/* Shared memory */ +static int shmem_release_pages(char *rel_area) +{ + int ret = 0; + + if (madvise(rel_area, nr_pages * page_size, MADV_REMOVE)) { + perror("madvise"); + ret = 1; + } + + return ret; +} + +static void shmem_allocate_area(void **alloc_area) +{ + *alloc_area = mmap(NULL, nr_pages * page_size, PROT_READ | PROT_WRITE, + MAP_ANONYMOUS | MAP_SHARED, -1, 0); + if (*alloc_area == MAP_FAILED) { + fprintf(stderr, "shared memory mmap failed\n"); + *alloc_area = NULL; + } +} + +struct uffd_test_ops { + unsigned long expected_ioctls; + void (*allocate_area)(void **alloc_area); + int (*release_pages)(char *rel_area); + void (*alias_mapping)(__u64 *start, size_t len, unsigned long offset); +}; + +#define SHMEM_EXPECTED_IOCTLS ((1 << _UFFDIO_WAKE) | \ + (1 << _UFFDIO_COPY) | \ + (1 << _UFFDIO_ZEROPAGE)) + +#define ANON_EXPECTED_IOCTLS ((1 << _UFFDIO_WAKE) | \ + (1 << _UFFDIO_COPY) | \ + (1 << _UFFDIO_ZEROPAGE) | \ + (1 << _UFFDIO_WRITEPROTECT)) + +static struct uffd_test_ops anon_uffd_test_ops = { + .expected_ioctls = ANON_EXPECTED_IOCTLS, + .allocate_area = anon_allocate_area, + .release_pages = anon_release_pages, + .alias_mapping = noop_alias_mapping, +}; + +static struct uffd_test_ops shmem_uffd_test_ops = { + .expected_ioctls = SHMEM_EXPECTED_IOCTLS, + .allocate_area = shmem_allocate_area, + .release_pages = shmem_release_pages, + .alias_mapping = noop_alias_mapping, +}; + +static struct uffd_test_ops hugetlb_uffd_test_ops = { + .expected_ioctls = UFFD_API_RANGE_IOCTLS_BASIC, + .allocate_area = hugetlb_allocate_area, + .release_pages = hugetlb_release_pages, + .alias_mapping = hugetlb_alias_mapping, +}; + +static struct uffd_test_ops *uffd_test_ops; + +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 wp_range(int ufd, __u64 start, __u64 len, bool wp) +{ + struct uffdio_writeprotect prms = { 0 }; + + /* Write protection page faults */ + prms.range.start = start; + prms.range.len = len; + /* Undo write-protect, do wakeup after that */ + prms.mode = wp ? UFFDIO_WRITEPROTECT_MODE_WP : 0; + + if (ioctl(ufd, UFFDIO_WRITEPROTECT, &prms)) { + fprintf(stderr, "clear WP failed for address 0x%Lx\n", start); + exit(1); + } +} + +static void *locking_thread(void *arg) +{ + unsigned long cpu = (unsigned long) arg; + struct random_data rand; + unsigned long page_nr = *(&(page_nr)); /* uninitialized warning */ + int32_t rand_nr; + unsigned long long count; + char randstate[64]; + unsigned int seed; + time_t start; + + if (bounces & BOUNCE_RANDOM) { + seed = (unsigned int) time(NULL) - bounces; + if (!(bounces & BOUNCE_RACINGFAULTS)) + seed += cpu; + bzero(&rand, sizeof(rand)); + bzero(&randstate, sizeof(randstate)); + if (initstate_r(seed, randstate, sizeof(randstate), &rand)) { + fprintf(stderr, "srandom_r error\n"); + exit(1); + } + } else { + page_nr = -bounces; + if (!(bounces & BOUNCE_RACINGFAULTS)) + page_nr += cpu * nr_pages_per_cpu; + } + + while (!finished) { + if (bounces & BOUNCE_RANDOM) { + if (random_r(&rand, &rand_nr)) { + fprintf(stderr, "random_r 1 error\n"); + exit(1); + } + page_nr = rand_nr; + if (sizeof(page_nr) > sizeof(rand_nr)) { + if (random_r(&rand, &rand_nr)) { + fprintf(stderr, "random_r 2 error\n"); + exit(1); + } + page_nr |= (((unsigned long) rand_nr) << 16) << + 16; + } + } else + page_nr += 1; + page_nr %= nr_pages; + + start = time(NULL); + if (bounces & BOUNCE_VERIFY) { + count = *area_count(area_dst, page_nr); + if (!count) { + fprintf(stderr, + "page_nr %lu wrong count %Lu %Lu\n", + page_nr, count, + count_verify[page_nr]); + exit(1); + } + + + /* + * We can't use bcmp (or memcmp) because that + * returns 0 erroneously if the memory is + * changing under it (even if the end of the + * page is never changing and always + * different). + */ +#if 1 + if (!my_bcmp(area_dst + page_nr * page_size, zeropage, + page_size)) { + fprintf(stderr, + "my_bcmp page_nr %lu wrong count %Lu %Lu\n", + page_nr, count, count_verify[page_nr]); + exit(1); + } +#else + unsigned long loops; + + loops = 0; + /* uncomment the below line to test with mutex */ + /* pthread_mutex_lock(area_mutex(area_dst, page_nr)); */ + while (!bcmp(area_dst + page_nr * page_size, zeropage, + page_size)) { + loops += 1; + if (loops > 10) + break; + } + /* uncomment below line to test with mutex */ + /* pthread_mutex_unlock(area_mutex(area_dst, page_nr)); */ + if (loops) { + fprintf(stderr, + "page_nr %lu all zero thread %lu %p %lu\n", + page_nr, cpu, area_dst + page_nr * page_size, + loops); + if (loops > 10) + exit(1); + } +#endif + } + + pthread_mutex_lock(area_mutex(area_dst, page_nr)); + count = *area_count(area_dst, page_nr); + if (count != count_verify[page_nr]) { + fprintf(stderr, + "page_nr %lu memory corruption %Lu %Lu\n", + page_nr, count, + count_verify[page_nr]); exit(1); + } + count++; + *area_count(area_dst, page_nr) = count_verify[page_nr] = count; + pthread_mutex_unlock(area_mutex(area_dst, page_nr)); + + if (time(NULL) - start > 1) + fprintf(stderr, + "userfault too slow %ld " + "possible false positive with overcommit\n", + time(NULL) - start); + } + + return NULL; +} + +static void retry_copy_page(int ufd, struct uffdio_copy *uffdio_copy, + unsigned long offset) +{ + uffd_test_ops->alias_mapping(&uffdio_copy->dst, + uffdio_copy->len, + offset); + if (ioctl(ufd, UFFDIO_COPY, uffdio_copy)) { + /* real retval in ufdio_copy.copy */ + if (uffdio_copy->copy != -EEXIST) { + fprintf(stderr, "UFFDIO_COPY retry error %Ld\n", + uffdio_copy->copy); + exit(1); + } + } else { + fprintf(stderr, "UFFDIO_COPY retry unexpected %Ld\n", + uffdio_copy->copy); exit(1); + } +} + +static int __copy_page(int ufd, unsigned long offset, bool retry) +{ + struct uffdio_copy uffdio_copy; + + if (offset >= nr_pages * page_size) { + fprintf(stderr, "unexpected offset %lu\n", offset); + exit(1); + } + uffdio_copy.dst = (unsigned long) area_dst + offset; + uffdio_copy.src = (unsigned long) area_src + offset; + uffdio_copy.len = page_size; + if (test_uffdio_wp) + uffdio_copy.mode = UFFDIO_COPY_MODE_WP; + else + uffdio_copy.mode = 0; + uffdio_copy.copy = 0; + if (ioctl(ufd, UFFDIO_COPY, &uffdio_copy)) { + /* real retval in ufdio_copy.copy */ + if (uffdio_copy.copy != -EEXIST) { + fprintf(stderr, "UFFDIO_COPY error %Ld\n", + uffdio_copy.copy); + exit(1); + } + } else if (uffdio_copy.copy != page_size) { + fprintf(stderr, "UFFDIO_COPY unexpected copy %Ld\n", + uffdio_copy.copy); exit(1); + } else { + if (test_uffdio_copy_eexist && retry) { + test_uffdio_copy_eexist = false; + retry_copy_page(ufd, &uffdio_copy, offset); + } + return 1; + } + return 0; +} + +static int copy_page_retry(int ufd, unsigned long offset) +{ + return __copy_page(ufd, offset, true); +} + +static int copy_page(int ufd, unsigned long offset) +{ + return __copy_page(ufd, offset, false); +} + +static int uffd_read_msg(int ufd, struct uffd_msg *msg) +{ + int ret = read(uffd, msg, sizeof(*msg)); + + if (ret != sizeof(*msg)) { + if (ret < 0) { + if (errno == EAGAIN) + return 1; + perror("blocking read error"); + } else { + fprintf(stderr, "short read\n"); + } + exit(1); + } + + return 0; +} + +static void uffd_handle_page_fault(struct uffd_msg *msg, + struct uffd_stats *stats) +{ + unsigned long offset; + + if (msg->event != UFFD_EVENT_PAGEFAULT) { + fprintf(stderr, "unexpected msg event %u\n", msg->event); + exit(1); + } + + if (msg->arg.pagefault.flags & UFFD_PAGEFAULT_FLAG_WP) { + wp_range(uffd, msg->arg.pagefault.address, page_size, false); + stats->wp_faults++; + } else { + /* Missing page faults */ + if (bounces & BOUNCE_VERIFY && + msg->arg.pagefault.flags & UFFD_PAGEFAULT_FLAG_WRITE) { + fprintf(stderr, "unexpected write fault\n"); + exit(1); + } + + offset = (char *)(unsigned long)msg->arg.pagefault.address - area_dst; + offset &= ~(page_size-1); + + if (copy_page(uffd, offset)) + stats->missing_faults++; + } +} + +static void *uffd_poll_thread(void *arg) +{ + struct uffd_stats *stats = (struct uffd_stats *)arg; + unsigned long cpu = stats->cpu; + struct pollfd pollfd[2]; + struct uffd_msg msg; + struct uffdio_register uffd_reg; + int ret; + char tmp_chr; + + pollfd[0].fd = uffd; + pollfd[0].events = POLLIN; + pollfd[1].fd = pipefd[cpu*2]; + pollfd[1].events = POLLIN; + + for (;;) { + ret = poll(pollfd, 2, -1); + if (!ret) { + fprintf(stderr, "poll error %d\n", ret); + exit(1); + } + if (ret < 0) { + perror("poll"); + exit(1); + } + if (pollfd[1].revents & POLLIN) { + if (read(pollfd[1].fd, &tmp_chr, 1) != 1) { + fprintf(stderr, "read pipefd error\n"); + exit(1); + } + break; + } + if (!(pollfd[0].revents & POLLIN)) { + fprintf(stderr, "pollfd[0].revents %d\n", + pollfd[0].revents); + exit(1); + } + if (uffd_read_msg(uffd, &msg)) + continue; + switch (msg.event) { + default: + fprintf(stderr, "unexpected msg event %u\n", + msg.event); exit(1); + break; + case UFFD_EVENT_PAGEFAULT: + uffd_handle_page_fault(&msg, stats); + break; + case UFFD_EVENT_FORK: + close(uffd); + uffd = msg.arg.fork.ufd; + pollfd[0].fd = uffd; + break; + case UFFD_EVENT_REMOVE: + uffd_reg.range.start = msg.arg.remove.start; + uffd_reg.range.len = msg.arg.remove.end - + msg.arg.remove.start; + if (ioctl(uffd, UFFDIO_UNREGISTER, &uffd_reg.range)) { + fprintf(stderr, "remove failure\n"); + exit(1); + } + break; + case UFFD_EVENT_REMAP: + area_dst = (char *)(unsigned long)msg.arg.remap.to; + break; + } + } + + return NULL; +} + +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 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). + */ + if (uffd_test_ops->release_pages(area_src)) + return 1; + + + 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) { + fprintf(stderr, "pipefd write error\n"); + return 1; + } + 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; +} + +static int userfaultfd_open(int features) +{ + struct uffdio_api uffdio_api; + + uffd = syscall(__NR_userfaultfd, O_CLOEXEC | O_NONBLOCK); + if (uffd < 0) { + fprintf(stderr, + "userfaultfd syscall not available in this kernel\n"); + return 1; + } + uffd_flags = fcntl(uffd, F_GETFD, NULL); + + uffdio_api.api = UFFD_API; + uffdio_api.features = features; + if (ioctl(uffd, UFFDIO_API, &uffdio_api)) { + fprintf(stderr, "UFFDIO_API\n"); + return 1; + } + if (uffdio_api.api != UFFD_API) { + fprintf(stderr, "UFFDIO_API error %Lu\n", uffdio_api.api); + 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; + unsigned long signalled = 0; + + if (test_type != TEST_HUGETLB) + split_nr_pages = (nr_pages + 1) / 2; + else + split_nr_pages = nr_pages; + + if (signal_test) { + sigbuf = &jbuf; + memset(&act, 0, sizeof(act)); + act.sa_sigaction = sighndl; + act.sa_flags = SA_SIGINFO; + if (sigaction(SIGBUS, &act, 0)) { + perror("sigaction"); + return 1; + } + lastnr = (unsigned long)-1; + } + + for (nr = 0; nr < split_nr_pages; nr++) { + int steps = 1; + unsigned long offset = nr * page_size; + + if (signal_test) { + if (sigsetjmp(*sigbuf, 1) != 0) { + if (steps == 1 && nr == lastnr) { + fprintf(stderr, "Signal repeated\n"); + return 1; + } + + 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]) { + fprintf(stderr, + "nr %lu memory corruption %Lu %Lu\n", + nr, count, + count_verify[nr]); + } + /* + * Trigger write protection if there is by writting + * the same value back. + */ + *area_count(area_dst, nr) = count; + } + + if (signal_test) + return signalled != split_nr_pages; + + if (test_type == TEST_HUGETLB) + return 0; + + area_dst = mremap(area_dst, nr_pages * page_size, nr_pages * page_size, + MREMAP_MAYMOVE | MREMAP_FIXED, area_src); + if (area_dst == MAP_FAILED) { + perror("mremap"); + exit(1); + } + + for (; nr < nr_pages; nr++) { + count = *area_count(area_dst, nr); + if (count != count_verify[nr]) { + fprintf(stderr, + "nr %lu memory corruption %Lu %Lu\n", + nr, count, + count_verify[nr]); exit(1); + } + /* + * Trigger write protection if there is by writting + * the same value back. + */ + *area_count(area_dst, nr) = count; + } + + if (uffd_test_ops->release_pages(area_dst)) + return 1; + + for (nr = 0; nr < nr_pages; nr++) { + if (my_bcmp(area_dst + nr * page_size, zeropage, page_size)) { + fprintf(stderr, "nr %lu is not zero\n", nr); + exit(1); + } + } + + 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) { + fprintf(stderr, "UFFDIO_ZEROPAGE retry error %Ld\n", + uffdio_zeropage->zeropage); + exit(1); + } + } else { + fprintf(stderr, "UFFDIO_ZEROPAGE retry unexpected %Ld\n", + uffdio_zeropage->zeropage); exit(1); + } +} + +static int __uffdio_zeropage(int ufd, unsigned long offset, bool retry) +{ + struct uffdio_zeropage uffdio_zeropage; + int ret; + unsigned long has_zeropage; + + has_zeropage = uffd_test_ops->expected_ioctls & (1 << _UFFDIO_ZEROPAGE); + + if (offset >= nr_pages * page_size) { + fprintf(stderr, "unexpected offset %lu\n", offset); + exit(1); + } + 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); + if (ret) { + /* real retval in ufdio_zeropage.zeropage */ + if (has_zeropage) { + if (uffdio_zeropage.zeropage == -EEXIST) { + fprintf(stderr, "UFFDIO_ZEROPAGE -EEXIST\n"); + exit(1); + } else { + fprintf(stderr, "UFFDIO_ZEROPAGE error %Ld\n", + uffdio_zeropage.zeropage); + exit(1); + } + } else { + if (uffdio_zeropage.zeropage != -EINVAL) { + fprintf(stderr, + "UFFDIO_ZEROPAGE not -EINVAL %Ld\n", + uffdio_zeropage.zeropage); + exit(1); + } + } + } else if (has_zeropage) { + if (uffdio_zeropage.zeropage != page_size) { + fprintf(stderr, "UFFDIO_ZEROPAGE unexpected %Ld\n", + uffdio_zeropage.zeropage); exit(1); + } else { + if (test_uffdio_zeropage_eexist && retry) { + test_uffdio_zeropage_eexist = false; + retry_uffdio_zeropage(ufd, &uffdio_zeropage, + offset); + } + return 1; + } + } else { + fprintf(stderr, + "UFFDIO_ZEROPAGE succeeded %Ld\n", + uffdio_zeropage.zeropage); exit(1); + } + + return 0; +} + +static int uffdio_zeropage(int ufd, unsigned long offset) +{ + return __uffdio_zeropage(ufd, offset, false); +} + +/* exercise UFFDIO_ZEROPAGE */ +static int userfaultfd_zeropage_test(void) +{ + struct uffdio_register uffdio_register; + unsigned long expected_ioctls; + + printf("testing UFFDIO_ZEROPAGE: "); + fflush(stdout); + + if (uffd_test_ops->release_pages(area_dst)) + return 1; + + if (userfaultfd_open(0) < 0) + return 1; + 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)) { + fprintf(stderr, "register failure\n"); + exit(1); + } + + expected_ioctls = uffd_test_ops->expected_ioctls; + if ((uffdio_register.ioctls & expected_ioctls) != + expected_ioctls) { + fprintf(stderr, + "unexpected missing ioctl for anon memory\n"); + exit(1); + } + + if (uffdio_zeropage(uffd, 0)) { + if (my_bcmp(area_dst, zeropage, page_size)) { + fprintf(stderr, "zeropage is not zero\n"); + exit(1); + } + } + + close(uffd); + printf("done.\n"); + return 0; +} + +static int userfaultfd_events_test(void) +{ + struct uffdio_register uffdio_register; + unsigned long expected_ioctls; + 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); + + if (uffd_test_ops->release_pages(area_dst)) + return 1; + + features = UFFD_FEATURE_EVENT_FORK | UFFD_FEATURE_EVENT_REMAP | + UFFD_FEATURE_EVENT_REMOVE; + if (userfaultfd_open(features) < 0) + return 1; + 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)) { + fprintf(stderr, "register failure\n"); + exit(1); + } + + expected_ioctls = uffd_test_ops->expected_ioctls; + if ((uffdio_register.ioctls & expected_ioctls) != expected_ioctls) { + fprintf(stderr, "unexpected missing ioctl for anon memory\n"); + exit(1); + } + + if (pthread_create(&uffd_mon, &attr, uffd_poll_thread, &stats)) { + perror("uffd_poll_thread create"); + exit(1); + } + + pid = fork(); + if (pid < 0) { + perror("fork"); + exit(1); + } + + if (!pid) + return faulting_process(0); + + waitpid(pid, &err, 0); + if (err) { + fprintf(stderr, "faulting process failed\n"); + exit(1); + } + + if (write(pipefd[1], &c, sizeof(c)) != sizeof(c)) { + perror("pipe write"); + exit(1); + } + if (pthread_join(uffd_mon, NULL)) + return 1; + + close(uffd); + + uffd_stats_report(&stats, 1); + + return stats.missing_faults != nr_pages; +} + +static int userfaultfd_sig_test(void) +{ + struct uffdio_register uffdio_register; + unsigned long expected_ioctls; + 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); + + if (uffd_test_ops->release_pages(area_dst)) + return 1; + + features = UFFD_FEATURE_EVENT_FORK|UFFD_FEATURE_SIGBUS; + if (userfaultfd_open(features) < 0) + return 1; + 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)) { + fprintf(stderr, "register failure\n"); + exit(1); + } + + expected_ioctls = uffd_test_ops->expected_ioctls; + if ((uffdio_register.ioctls & expected_ioctls) != expected_ioctls) { + fprintf(stderr, "unexpected missing ioctl for anon memory\n"); + exit(1); + } + + if (faulting_process(1)) { + fprintf(stderr, "faulting process failed\n"); + exit(1); + } + + if (uffd_test_ops->release_pages(area_dst)) + return 1; + + if (pthread_create(&uffd_mon, &attr, uffd_poll_thread, &stats)) { + perror("uffd_poll_thread create"); + exit(1); + } + + pid = fork(); + if (pid < 0) { + perror("fork"); + exit(1); + } + + if (!pid) + exit(faulting_process(2)); + + waitpid(pid, &err, 0); + if (err) { + fprintf(stderr, "faulting process failed\n"); + exit(1); + } + + if (write(pipefd[1], &c, sizeof(c)) != sizeof(c)) { + perror("pipe write"); + exit(1); + } + if (pthread_join(uffd_mon, (void **)&userfaults)) + return 1; + + printf("done.\n"); + if (userfaults) + fprintf(stderr, "Signal test failed, userfaults: %ld\n", + userfaults); + close(uffd); + return userfaults != 0; +} + +static int userfaultfd_stress(void) +{ + void *area; + char *tmp_area; + unsigned long nr; + struct uffdio_register uffdio_register; + unsigned long cpu; + int err; + struct uffd_stats uffd_stats[nr_cpus]; + + uffd_test_ops->allocate_area((void **)&area_src); + if (!area_src) + return 1; + uffd_test_ops->allocate_area((void **)&area_dst); + if (!area_dst) + return 1; + + if (userfaultfd_open(0) < 0) + return 1; + + count_verify = malloc(nr_pages * sizeof(unsigned long long)); + if (!count_verify) { + perror("count_verify"); + return 1; + } + + for (nr = 0; nr < nr_pages; nr++) { + *area_mutex(area_src, nr) = (pthread_mutex_t) + PTHREAD_MUTEX_INITIALIZER; + count_verify[nr] = *area_count(area_src, nr) = 1; + /* + * In the transition between 255 to 256, powerpc will + * read out of order in my_bcmp and see both bytes as + * zero, so leave a placeholder below always non-zero + * after the count, to avoid my_bcmp to trigger false + * positives. + */ + *(area_count(area_src, nr) + 1) = 1; + } + + pipefd = malloc(sizeof(int) * nr_cpus * 2); + if (!pipefd) { + perror("pipefd"); + return 1; + } + for (cpu = 0; cpu < nr_cpus; cpu++) { + if (pipe2(&pipefd[cpu*2], O_CLOEXEC | O_NONBLOCK)) { + perror("pipe"); + return 1; + } + } + + if (posix_memalign(&area, page_size, page_size)) { + fprintf(stderr, "out of memory\n"); + return 1; + } + zeropage = area; + bzero(zeropage, page_size); + + pthread_mutex_lock(&uffd_read_mutex); + + pthread_attr_init(&attr); + pthread_attr_setstacksize(&attr, 16*1024*1024); + + err = 0; + while (bounces--) { + unsigned long expected_ioctls; + + 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"); + 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)) { + fprintf(stderr, "register failure\n"); + return 1; + } + expected_ioctls = uffd_test_ops->expected_ioctls; + if ((uffdio_register.ioctls & expected_ioctls) != + expected_ioctls) { + fprintf(stderr, + "unexpected missing ioctl for anon memory\n"); + return 1; + } + + if (area_dst_alias) { + uffdio_register.range.start = (unsigned long) + area_dst_alias; + if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register)) { + fprintf(stderr, "register failure alias\n"); + return 1; + } + } + + /* + * 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. + */ + if (uffd_test_ops->release_pages(area_dst)) + return 1; + + 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)) { + fprintf(stderr, "unregister failure\n"); + return 1; + } + if (area_dst_alias) { + uffdio_register.range.start = (unsigned long) area_dst; + if (ioctl(uffd, UFFDIO_UNREGISTER, + &uffdio_register.range)) { + fprintf(stderr, "unregister failure alias\n"); + return 1; + } + } + + /* verification */ + if (bounces & BOUNCE_VERIFY) { + for (nr = 0; nr < nr_pages; nr++) { + if (*area_count(area_dst, nr) != count_verify[nr]) { + fprintf(stderr, + "error area_count %Lu %Lu %lu\n", + *area_count(area_src, nr), + count_verify[nr], + nr); + err = 1; + bounces = 0; + } + } + } + + /* prepare next bounce */ + tmp_area = area_src; + area_src = area_dst; + area_dst = tmp_area; + + tmp_area = area_src_alias; + area_src_alias = area_dst_alias; + area_dst_alias = tmp_area; + + uffd_stats_report(uffd_stats, nr_cpus); + } + + if (err) + return err; + + close(uffd); + return userfaultfd_zeropage_test() || userfaultfd_sig_test() + || userfaultfd_events_test(); +} + +/* + * Copied from mlock2-tests.c + */ +unsigned long default_huge_page_size(void) +{ + unsigned long hps = 0; + char *line = NULL; + size_t linelen = 0; + FILE *f = fopen("/proc/meminfo", "r"); + + if (!f) + return 0; + while (getline(&line, &linelen, f) > 0) { + if (sscanf(line, "Hugepagesize: %lu kB", &hps) == 1) { + hps <<= 10; + break; + } + } + + free(line); + fclose(f); + return hps; +} + +static void set_test_type(const char *type) +{ + if (!strcmp(type, "anon")) { + test_type = TEST_ANON; + uffd_test_ops = &anon_uffd_test_ops; + /* Only enable write-protect test for anonymous test */ + test_uffdio_wp = true; + } 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; + } else if (!strcmp(type, "shmem")) { + map_shared = true; + test_type = TEST_SHMEM; + uffd_test_ops = &shmem_uffd_test_ops; + } else { + fprintf(stderr, "Unknown test type: %s\n", type); exit(1); + } + + if (test_type == TEST_HUGETLB) + page_size = default_huge_page_size(); + else + page_size = sysconf(_SC_PAGE_SIZE); + + if (!page_size) { + fprintf(stderr, "Unable to determine page size\n"); + exit(2); + } + if ((unsigned long) area_count(NULL, 0) + sizeof(unsigned long long) * 2 + > page_size) { + fprintf(stderr, "Impossible to run this test\n"); + exit(2); + } +} + +static void sigalrm(int sig) +{ + if (sig != SIGALRM) + abort(); + test_uffdio_copy_eexist = true; + test_uffdio_zeropage_eexist = true; + alarm(ALARM_INTERVAL_SECS); +} + +int main(int argc, char **argv) +{ + if (argc < 4) + usage(); + + if (signal(SIGALRM, sigalrm) == SIG_ERR) { + fprintf(stderr, "failed to arm SIGALRM"); + exit(1); + } + alarm(ALARM_INTERVAL_SECS); + + set_test_type(argv[1]); + + nr_cpus = sysconf(_SC_NPROCESSORS_ONLN); + nr_pages_per_cpu = atol(argv[2]) * 1024*1024 / page_size / + nr_cpus; + if (!nr_pages_per_cpu) { + fprintf(stderr, "invalid MiB\n"); + usage(); + } + + bounces = atoi(argv[3]); + if (bounces <= 0) { + fprintf(stderr, "invalid bounces\n"); + usage(); + } + nr_pages = nr_pages_per_cpu * nr_cpus; + + if (test_type == TEST_HUGETLB) { + if (argc < 5) + usage(); + huge_fd = open(argv[4], O_CREAT | O_RDWR, 0755); + if (huge_fd < 0) { + fprintf(stderr, "Open of %s failed", argv[3]); + perror("open"); + exit(1); + } + if (ftruncate(huge_fd, 0)) { + fprintf(stderr, "ftruncate %s to size 0 failed", argv[3]); + perror("ftruncate"); + exit(1); + } + } + 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 */ |