tools/testing/selftests/kvm/demand_paging_test.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * KVM demand paging test
   4  * Adapted from dirty_log_test.c
   5  *
   6  * Copyright (C) 2018, Red Hat, Inc.
   7  * Copyright (C) 2019, Google, Inc.
   8  */
   9
  10 #define _GNU_SOURCE /* for program_invocation_name */
  11
  12 #include <stdio.h>
  13 #include <stdlib.h>
  14 #include <sys/syscall.h>
  15 #include <unistd.h>
  16 #include <asm/unistd.h>
  17 #include <time.h>
  18 #include <poll.h>
  19 #include <pthread.h>
  20 #include <linux/bitmap.h>
  21 #include <linux/bitops.h>
  22 #include <linux/userfaultfd.h>
  23
  24 #include "test_util.h"
  25 #include "kvm_util.h"
  26 #include "processor.h"
  27
  28 #ifdef __NR_userfaultfd
  29
  30 /* The memory slot index demand page */
  31 #define TEST_MEM_SLOT_INDEX             1
  32
  33 /* Default guest test virtual memory offset */
  34 #define DEFAULT_GUEST_TEST_MEM          0xc0000000
  35
  36 #define DEFAULT_GUEST_TEST_MEM_SIZE (1 << 30) /* 1G */
  37
  38 #ifdef PRINT_PER_PAGE_UPDATES
  39 #define PER_PAGE_DEBUG(...) printf(__VA_ARGS__)
  40 #else
  41 #define PER_PAGE_DEBUG(...) _no_printf(__VA_ARGS__)
  42 #endif
  43
  44 #ifdef PRINT_PER_VCPU_UPDATES
  45 #define PER_VCPU_DEBUG(...) printf(__VA_ARGS__)
  46 #else
  47 #define PER_VCPU_DEBUG(...) _no_printf(__VA_ARGS__)
  48 #endif
  49
  50 #define MAX_VCPUS 512
  51
  52 /*
  53  * Guest/Host shared variables. Ensure addr_gva2hva() and/or
  54  * sync_global_to/from_guest() are used when accessing from
  55  * the host. READ/WRITE_ONCE() should also be used with anything
  56  * that may change.
  57  */
  58 static uint64_t host_page_size;
  59 static uint64_t guest_page_size;
  60
  61 static char *guest_data_prototype;
  62
  63 /*
  64  * Guest physical memory offset of the testing memory slot.
  65  * This will be set to the topmost valid physical address minus
  66  * the test memory size.
  67  */
  68 static uint64_t guest_test_phys_mem;
  69
  70 /*
  71  * Guest virtual memory offset of the testing memory slot.
  72  * Must not conflict with identity mapped test code.
  73  */
  74 static uint64_t guest_test_virt_mem = DEFAULT_GUEST_TEST_MEM;
  75
  76 struct vcpu_args {
  77         uint64_t gva;
  78         uint64_t pages;
  79
  80         /* Only used by the host userspace part of the vCPU thread */
  81         int vcpu_id;
  82         struct kvm_vm *vm;
  83 };
  84
  85 static struct vcpu_args vcpu_args[MAX_VCPUS];
  86
  87 /*
  88  * Continuously write to the first 8 bytes of each page in the demand paging
  89  * memory region.
  90  */
  91 static void guest_code(uint32_t vcpu_id)
  92 {
  93         uint64_t gva;
  94         uint64_t pages;
  95         int i;
  96
  97         /* Make sure vCPU args data structure is not corrupt. */
  98         GUEST_ASSERT(vcpu_args[vcpu_id].vcpu_id == vcpu_id);
  99
 100         gva = vcpu_args[vcpu_id].gva;
 101         pages = vcpu_args[vcpu_id].pages;
 102
 103         for (i = 0; i < pages; i++) {
 104                 uint64_t addr = gva + (i * guest_page_size);
 105
 106                 addr &= ~(host_page_size - 1);
 107                 *(uint64_t *)addr = 0x0123456789ABCDEF;
 108         }
 109
 110         GUEST_SYNC(1);
 111 }
 112
 113 static void *vcpu_worker(void *data)
 114 {
 115         int ret;
 116         struct vcpu_args *args = (struct vcpu_args *)data;
 117         struct kvm_vm *vm = args->vm;
 118         int vcpu_id = args->vcpu_id;
 119         struct kvm_run *run;
 120         struct timespec start;
 121         struct timespec end;
 122
 123         vcpu_args_set(vm, vcpu_id, 1, vcpu_id);
 124         run = vcpu_state(vm, vcpu_id);
 125
 126         clock_gettime(CLOCK_MONOTONIC, &start);
 127
 128         /* Let the guest access its memory */
 129         ret = _vcpu_run(vm, vcpu_id);
 130         TEST_ASSERT(ret == 0, "vcpu_run failed: %d\n", ret);
 131         if (get_ucall(vm, vcpu_id, NULL) != UCALL_SYNC) {
 132                 TEST_ASSERT(false,
 133                             "Invalid guest sync status: exit_reason=%s\n",
 134                             exit_reason_str(run->exit_reason));
 135         }
 136
 137         clock_gettime(CLOCK_MONOTONIC, &end);
 138         PER_VCPU_DEBUG("vCPU %d execution time: %lld.%.9lds\n", vcpu_id,
 139                        (long long)(timespec_diff(start, end).tv_sec),
 140                        timespec_diff(start, end).tv_nsec);
 141
 142         return NULL;
 143 }
 144
 145 #define PAGE_SHIFT_4K  12
 146 #define PTES_PER_4K_PT 512
 147
 148 static struct kvm_vm *create_vm(enum vm_guest_mode mode, int vcpus,
 149                                 uint64_t vcpu_memory_bytes)
 150 {
 151         struct kvm_vm *vm;
 152         uint64_t pages = DEFAULT_GUEST_PHY_PAGES;
 153
 154         /* Account for a few pages per-vCPU for stacks */
 155         pages += DEFAULT_STACK_PGS * vcpus;
 156
 157         /*
 158          * Reserve twice the ammount of memory needed to map the test region and
 159          * the page table / stacks region, at 4k, for page tables. Do the
 160          * calculation with 4K page size: the smallest of all archs. (e.g., 64K
 161          * page size guest will need even less memory for page tables).
 162          */
 163         pages += (2 * pages) / PTES_PER_4K_PT;
 164         pages += ((2 * vcpus * vcpu_memory_bytes) >> PAGE_SHIFT_4K) /
 165                  PTES_PER_4K_PT;
 166         pages = vm_adjust_num_guest_pages(mode, pages);
 167
 168         pr_info("Testing guest mode: %s\n", vm_guest_mode_string(mode));
 169
 170         vm = _vm_create(mode, pages, O_RDWR);
 171         kvm_vm_elf_load(vm, program_invocation_name, 0, 0);
 172 #ifdef __x86_64__
 173         vm_create_irqchip(vm);
 174 #endif
 175         return vm;
 176 }
 177
 178 static int handle_uffd_page_request(int uffd, uint64_t addr)
 179 {
 180         pid_t tid;
 181         struct timespec start;
 182         struct timespec end;
 183         struct uffdio_copy copy;
 184         int r;
 185
 186         tid = syscall(__NR_gettid);
 187
 188         copy.src = (uint64_t)guest_data_prototype;
 189         copy.dst = addr;
 190         copy.len = host_page_size;
 191         copy.mode = 0;
 192
 193         clock_gettime(CLOCK_MONOTONIC, &start);
 194
 195         r = ioctl(uffd, UFFDIO_COPY, &copy);
 196         if (r == -1) {
 197                 pr_info("Failed Paged in 0x%lx from thread %d with errno: %d\n",
 198                         addr, tid, errno);
 199                 return r;
 200         }
 201
 202         clock_gettime(CLOCK_MONOTONIC, &end);
 203
 204         PER_PAGE_DEBUG("UFFDIO_COPY %d \t%lld ns\n", tid,
 205                        (long long)timespec_to_ns(timespec_diff(start, end)));
 206         PER_PAGE_DEBUG("Paged in %ld bytes at 0x%lx from thread %d\n",
 207                        host_page_size, addr, tid);
 208
 209         return 0;
 210 }
 211
 212 bool quit_uffd_thread;
 213
 214 struct uffd_handler_args {
 215         int uffd;
 216         int pipefd;
 217         useconds_t delay;
 218 };
 219
 220 static void *uffd_handler_thread_fn(void *arg)
 221 {
 222         struct uffd_handler_args *uffd_args = (struct uffd_handler_args *)arg;
 223         int uffd = uffd_args->uffd;
 224         int pipefd = uffd_args->pipefd;
 225         useconds_t delay = uffd_args->delay;
 226         int64_t pages = 0;
 227         struct timespec start;
 228         struct timespec end;
 229
 230         clock_gettime(CLOCK_MONOTONIC, &start);
 231         while (!quit_uffd_thread) {
 232                 struct uffd_msg msg;
 233                 struct pollfd pollfd[2];
 234                 char tmp_chr;
 235                 int r;
 236                 uint64_t addr;
 237
 238                 pollfd[0].fd = uffd;
 239                 pollfd[0].events = POLLIN;
 240                 pollfd[1].fd = pipefd;
 241                 pollfd[1].events = POLLIN;
 242
 243                 r = poll(pollfd, 2, -1);
 244                 switch (r) {
 245                 case -1:
 246                         pr_info("poll err");
 247                         continue;
 248                 case 0:
 249                         continue;
 250                 case 1:
 251                         break;
 252                 default:
 253                         pr_info("Polling uffd returned %d", r);
 254                         return NULL;
 255                 }
 256
 257                 if (pollfd[0].revents & POLLERR) {
 258                         pr_info("uffd revents has POLLERR");
 259                         return NULL;
 260                 }
 261
 262                 if (pollfd[1].revents & POLLIN) {
 263                         r = read(pollfd[1].fd, &tmp_chr, 1);
 264                         TEST_ASSERT(r == 1,
 265                                     "Error reading pipefd in UFFD thread\n");
 266                         return NULL;
 267                 }
 268
 269                 if (!pollfd[0].revents & POLLIN)
 270                         continue;
 271
 272                 r = read(uffd, &msg, sizeof(msg));
 273                 if (r == -1) {
 274                         if (errno == EAGAIN)
 275                                 continue;
 276                         pr_info("Read of uffd gor errno %d", errno);
 277                         return NULL;
 278                 }
 279
 280                 if (r != sizeof(msg)) {
 281                         pr_info("Read on uffd returned unexpected size: %d bytes", r);
 282                         return NULL;
 283                 }
 284
 285                 if (!(msg.event & UFFD_EVENT_PAGEFAULT))
 286                         continue;
 287
 288                 if (delay)
 289                         usleep(delay);
 290                 addr =  msg.arg.pagefault.address;
 291                 r = handle_uffd_page_request(uffd, addr);
 292                 if (r < 0)
 293                         return NULL;
 294                 pages++;
 295         }
 296
 297         clock_gettime(CLOCK_MONOTONIC, &end);
 298         PER_VCPU_DEBUG("userfaulted %ld pages over %lld.%.9lds. (%f/sec)\n",
 299                        pages, (long long)(timespec_diff(start, end).tv_sec),
 300                        timespec_diff(start, end).tv_nsec, pages /
 301                        ((double)timespec_diff(start, end).tv_sec +
 302                         (double)timespec_diff(start, end).tv_nsec / 100000000.0));
 303
 304         return NULL;
 305 }
 306
 307 static int setup_demand_paging(struct kvm_vm *vm,
 308                                pthread_t *uffd_handler_thread, int pipefd,
 309                                useconds_t uffd_delay,
 310                                struct uffd_handler_args *uffd_args,
 311                                void *hva, uint64_t len)
 312 {
 313         int uffd;
 314         struct uffdio_api uffdio_api;
 315         struct uffdio_register uffdio_register;
 316
 317         uffd = syscall(__NR_userfaultfd, O_CLOEXEC | O_NONBLOCK);
 318         if (uffd == -1) {
 319                 pr_info("uffd creation failed\n");
 320                 return -1;
 321         }
 322
 323         uffdio_api.api = UFFD_API;
 324         uffdio_api.features = 0;
 325         if (ioctl(uffd, UFFDIO_API, &uffdio_api) == -1) {
 326                 pr_info("ioctl uffdio_api failed\n");
 327                 return -1;
 328         }
 329
 330         uffdio_register.range.start = (uint64_t)hva;
 331         uffdio_register.range.len = len;
 332         uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
 333         if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register) == -1) {
 334                 pr_info("ioctl uffdio_register failed\n");
 335                 return -1;
 336         }
 337
 338         if ((uffdio_register.ioctls & UFFD_API_RANGE_IOCTLS) !=
 339                         UFFD_API_RANGE_IOCTLS) {
 340                 pr_info("unexpected userfaultfd ioctl set\n");
 341                 return -1;
 342         }
 343
 344         uffd_args->uffd = uffd;
 345         uffd_args->pipefd = pipefd;
 346         uffd_args->delay = uffd_delay;
 347         pthread_create(uffd_handler_thread, NULL, uffd_handler_thread_fn,
 348                        uffd_args);
 349
 350         PER_VCPU_DEBUG("Created uffd thread for HVA range [%p, %p)\n",
 351                        hva, hva + len);
 352
 353         return 0;
 354 }
 355
 356 static void run_test(enum vm_guest_mode mode, bool use_uffd,
 357                      useconds_t uffd_delay, int vcpus,
 358                      uint64_t vcpu_memory_bytes)
 359 {
 360         pthread_t *vcpu_threads;
 361         pthread_t *uffd_handler_threads = NULL;
 362         struct uffd_handler_args *uffd_args = NULL;
 363         int *pipefds = NULL;
 364         struct kvm_vm *vm;
 365         uint64_t guest_num_pages;
 366         int vcpu_id;
 367         int r;
 368         struct timespec start;
 369         struct timespec end;
 370
 371         vm = create_vm(mode, vcpus, vcpu_memory_bytes);
 372
 373         guest_page_size = vm_get_page_size(vm);
 374
 375         TEST_ASSERT(vcpu_memory_bytes % guest_page_size == 0,
 376                     "Guest memory size is not guest page size aligned.");
 377
 378         guest_num_pages = (vcpus * vcpu_memory_bytes) / guest_page_size;
 379         guest_num_pages = vm_adjust_num_guest_pages(mode, guest_num_pages);
 380
 381         /*
 382          * If there should be more memory in the guest test region than there
 383          * can be pages in the guest, it will definitely cause problems.
 384          */
 385         TEST_ASSERT(guest_num_pages < vm_get_max_gfn(vm),
 386                     "Requested more guest memory than address space allows.\n"
 387                     "    guest pages: %lx max gfn: %x vcpus: %d wss: %lx]\n",
 388                     guest_num_pages, vm_get_max_gfn(vm), vcpus,
 389                     vcpu_memory_bytes);
 390
 391         host_page_size = getpagesize();
 392         TEST_ASSERT(vcpu_memory_bytes % host_page_size == 0,
 393                     "Guest memory size is not host page size aligned.");
 394
 395         guest_test_phys_mem = (vm_get_max_gfn(vm) - guest_num_pages) *
 396                               guest_page_size;
 397         guest_test_phys_mem &= ~(host_page_size - 1);
 398
 399 #ifdef __s390x__
 400         /* Align to 1M (segment size) */
 401         guest_test_phys_mem &= ~((1 << 20) - 1);
 402 #endif
 403
 404         pr_info("guest physical test memory offset: 0x%lx\n", guest_test_phys_mem);
 405
 406         /* Add an extra memory slot for testing demand paging */
 407         vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS,
 408                                     guest_test_phys_mem,
 409                                     TEST_MEM_SLOT_INDEX,
 410                                     guest_num_pages, 0);
 411
 412         /* Do mapping for the demand paging memory slot */
 413         virt_map(vm, guest_test_virt_mem, guest_test_phys_mem,
 414                  guest_num_pages * guest_page_size, 0);
 415
 416         ucall_init(vm, NULL);
 417
 418         guest_data_prototype = malloc(host_page_size);
 419         TEST_ASSERT(guest_data_prototype,
 420                     "Failed to allocate buffer for guest data pattern");
 421         memset(guest_data_prototype, 0xAB, host_page_size);
 422
 423         vcpu_threads = malloc(vcpus * sizeof(*vcpu_threads));
 424         TEST_ASSERT(vcpu_threads, "Memory allocation failed");
 425
 426         if (use_uffd) {
 427                 uffd_handler_threads =
 428                         malloc(vcpus * sizeof(*uffd_handler_threads));
 429                 TEST_ASSERT(uffd_handler_threads, "Memory allocation failed");
 430
 431                 uffd_args = malloc(vcpus * sizeof(*uffd_args));
 432                 TEST_ASSERT(uffd_args, "Memory allocation failed");
 433
 434                 pipefds = malloc(sizeof(int) * vcpus * 2);
 435                 TEST_ASSERT(pipefds, "Unable to allocate memory for pipefd");
 436         }
 437
 438         for (vcpu_id = 0; vcpu_id < vcpus; vcpu_id++) {
 439                 vm_paddr_t vcpu_gpa;
 440                 void *vcpu_hva;
 441
 442                 vm_vcpu_add_default(vm, vcpu_id, guest_code);
 443
 444                 vcpu_gpa = guest_test_phys_mem + (vcpu_id * vcpu_memory_bytes);
 445                 PER_VCPU_DEBUG("Added VCPU %d with test mem gpa [%lx, %lx)\n",
 446                                vcpu_id, vcpu_gpa, vcpu_gpa + vcpu_memory_bytes);
 447
 448                 /* Cache the HVA pointer of the region */
 449                 vcpu_hva = addr_gpa2hva(vm, vcpu_gpa);
 450
 451                 if (use_uffd) {
 452                         /*
 453                          * Set up user fault fd to handle demand paging
 454                          * requests.
 455                          */
 456                         r = pipe2(&pipefds[vcpu_id * 2],
 457                                   O_CLOEXEC | O_NONBLOCK);
 458                         TEST_ASSERT(!r, "Failed to set up pipefd");
 459
 460                         r = setup_demand_paging(vm,
 461                                                 &uffd_handler_threads[vcpu_id],
 462                                                 pipefds[vcpu_id * 2],
 463                                                 uffd_delay, &uffd_args[vcpu_id],
 464                                                 vcpu_hva, vcpu_memory_bytes);
 465                         if (r < 0)
 466                                 exit(-r);
 467                 }
 468
 469 #ifdef __x86_64__
 470                 vcpu_set_cpuid(vm, vcpu_id, kvm_get_supported_cpuid());
 471 #endif
 472
 473                 vcpu_args[vcpu_id].vm = vm;
 474                 vcpu_args[vcpu_id].vcpu_id = vcpu_id;
 475                 vcpu_args[vcpu_id].gva = guest_test_virt_mem +
 476                                          (vcpu_id * vcpu_memory_bytes);
 477                 vcpu_args[vcpu_id].pages = vcpu_memory_bytes / guest_page_size;
 478         }
 479
 480         /* Export the shared variables to the guest */
 481         sync_global_to_guest(vm, host_page_size);
 482         sync_global_to_guest(vm, guest_page_size);
 483         sync_global_to_guest(vm, vcpu_args);
 484
 485         pr_info("Finished creating vCPUs and starting uffd threads\n");
 486
 487         clock_gettime(CLOCK_MONOTONIC, &start);
 488
 489         for (vcpu_id = 0; vcpu_id < vcpus; vcpu_id++) {
 490                 pthread_create(&vcpu_threads[vcpu_id], NULL, vcpu_worker,
 491                                &vcpu_args[vcpu_id]);
 492         }
 493
 494         pr_info("Started all vCPUs\n");
 495
 496         /* Wait for the vcpu threads to quit */
 497         for (vcpu_id = 0; vcpu_id < vcpus; vcpu_id++) {
 498                 pthread_join(vcpu_threads[vcpu_id], NULL);
 499                 PER_VCPU_DEBUG("Joined thread for vCPU %d\n", vcpu_id);
 500         }
 501
 502         pr_info("All vCPU threads joined\n");
 503
 504         clock_gettime(CLOCK_MONOTONIC, &end);
 505
 506         if (use_uffd) {
 507                 char c;
 508
 509                 /* Tell the user fault fd handler threads to quit */
 510                 for (vcpu_id = 0; vcpu_id < vcpus; vcpu_id++) {
 511                         r = write(pipefds[vcpu_id * 2 + 1], &c, 1);
 512                         TEST_ASSERT(r == 1, "Unable to write to pipefd");
 513
 514                         pthread_join(uffd_handler_threads[vcpu_id], NULL);
 515                 }
 516         }
 517
 518         pr_info("Total guest execution time: %lld.%.9lds\n",
 519                 (long long)(timespec_diff(start, end).tv_sec),
 520                 timespec_diff(start, end).tv_nsec);
 521         pr_info("Overall demand paging rate: %f pgs/sec\n",
 522                 guest_num_pages / ((double)timespec_diff(start, end).tv_sec +
 523                 (double)timespec_diff(start, end).tv_nsec / 100000000.0));
 524
 525         ucall_uninit(vm);
 526         kvm_vm_free(vm);
 527
 528         free(guest_data_prototype);
 529         free(vcpu_threads);
 530         if (use_uffd) {
 531                 free(uffd_handler_threads);
 532                 free(uffd_args);
 533                 free(pipefds);
 534         }
 535 }
 536
 537 struct guest_mode {
 538         bool supported;
 539         bool enabled;
 540 };
 541 static struct guest_mode guest_modes[NUM_VM_MODES];
 542
 543 #define guest_mode_init(mode, supported, enabled) ({ \
 544         guest_modes[mode] = (struct guest_mode){ supported, enabled }; \
 545 })
 546
 547 static void help(char *name)
 548 {
 549         int i;
 550
 551         puts("");
 552         printf("usage: %s [-h] [-m mode] [-u] [-d uffd_delay_usec]\n"
 553                "          [-b memory] [-v vcpus]\n", name);
 554         printf(" -m: specify the guest mode ID to test\n"
 555                "     (default: test all supported modes)\n"
 556                "     This option may be used multiple times.\n"
 557                "     Guest mode IDs:\n");
 558         for (i = 0; i < NUM_VM_MODES; ++i) {
 559                 printf("         %d:    %s%s\n", i, vm_guest_mode_string(i),
 560                        guest_modes[i].supported ? " (supported)" : "");
 561         }
 562         printf(" -u: use User Fault FD to handle vCPU page\n"
 563                "     faults.\n");
 564         printf(" -d: add a delay in usec to the User Fault\n"
 565                "     FD handler to simulate demand paging\n"
 566                "     overheads. Ignored without -u.\n");
 567         printf(" -b: specify the size of the memory region which should be\n"
 568                "     demand paged by each vCPU. e.g. 10M or 3G.\n"
 569                "     Default: 1G\n");
 570         printf(" -v: specify the number of vCPUs to run.\n");
 571         puts("");
 572         exit(0);
 573 }
 574
 575 int main(int argc, char *argv[])
 576 {
 577         bool mode_selected = false;
 578         uint64_t vcpu_memory_bytes = DEFAULT_GUEST_TEST_MEM_SIZE;
 579         int vcpus = 1;
 580         unsigned int mode;
 581         int opt, i;
 582         bool use_uffd = false;
 583         useconds_t uffd_delay = 0;
 584
 585 #ifdef __x86_64__
 586         guest_mode_init(VM_MODE_PXXV48_4K, true, true);
 587 #endif
 588 #ifdef __aarch64__
 589         guest_mode_init(VM_MODE_P40V48_4K, true, true);
 590         guest_mode_init(VM_MODE_P40V48_64K, true, true);
 591         {
 592                 unsigned int limit = kvm_check_cap(KVM_CAP_ARM_VM_IPA_SIZE);
 593
 594                 if (limit >= 52)
 595                         guest_mode_init(VM_MODE_P52V48_64K, true, true);
 596                 if (limit >= 48) {
 597                         guest_mode_init(VM_MODE_P48V48_4K, true, true);
 598                         guest_mode_init(VM_MODE_P48V48_64K, true, true);
 599                 }
 600         }
 601 #endif
 602 #ifdef __s390x__
 603         guest_mode_init(VM_MODE_P40V48_4K, true, true);
 604 #endif
 605
 606         while ((opt = getopt(argc, argv, "hm:ud:b:v:")) != -1) {
 607                 switch (opt) {
 608                 case 'm':
 609                         if (!mode_selected) {
 610                                 for (i = 0; i < NUM_VM_MODES; ++i)
 611                                         guest_modes[i].enabled = false;
 612                                 mode_selected = true;
 613                         }
 614                         mode = strtoul(optarg, NULL, 10);
 615                         TEST_ASSERT(mode < NUM_VM_MODES,
 616                                     "Guest mode ID %d too big", mode);
 617                         guest_modes[mode].enabled = true;
 618                         break;
 619                 case 'u':
 620                         use_uffd = true;
 621                         break;
 622                 case 'd':
 623                         uffd_delay = strtoul(optarg, NULL, 0);
 624                         TEST_ASSERT(uffd_delay >= 0,
 625                                     "A negative UFFD delay is not supported.");
 626                         break;
 627                 case 'b':
 628                         vcpu_memory_bytes = parse_size(optarg);
 629                         break;
 630                 case 'v':
 631                         vcpus = atoi(optarg);
 632                         TEST_ASSERT(vcpus > 0,
 633                                     "Must have a positive number of vCPUs");
 634                         TEST_ASSERT(vcpus <= MAX_VCPUS,
 635                                     "This test does not currently support\n"
 636                                     "more than %d vCPUs.", MAX_VCPUS);
 637                         break;
 638                 case 'h':
 639                 default:
 640                         help(argv[0]);
 641                         break;
 642                 }
 643         }
 644
 645         for (i = 0; i < NUM_VM_MODES; ++i) {
 646                 if (!guest_modes[i].enabled)
 647                         continue;
 648                 TEST_ASSERT(guest_modes[i].supported,
 649                             "Guest mode ID %d (%s) not supported.",
 650                             i, vm_guest_mode_string(i));
 651                 run_test(i, use_uffd, uffd_delay, vcpus, vcpu_memory_bytes);
 652         }
 653
 654         return 0;
 655 }
 656
 657 #else /* __NR_userfaultfd */
 658
 659 #warning "missing __NR_userfaultfd definition"
 660
 661 int main(void)
 662 {
 663         printf("skip: Skipping userfaultfd test (missing __NR_userfaultfd)\n");
 664         return KSFT_SKIP;
 665 }
 666
 667 #endif /* __NR_userfaultfd */