tools/testing/selftests/kvm/dirty_log_test.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * KVM dirty page logging test
   4  *
   5  * Copyright (C) 2018, Red Hat, Inc.
   6  */
   7
   8 #define _GNU_SOURCE /* for program_invocation_name */
   9
  10 #include <stdio.h>
  11 #include <stdlib.h>
  12 #include <unistd.h>
  13 #include <time.h>
  14 #include <pthread.h>
  15 #include <linux/bitmap.h>
  16 #include <linux/bitops.h>
  17
  18 #include "test_util.h"
  19 #include "kvm_util.h"
  20 #include "processor.h"
  21
  22 #define DEBUG printf
  23
  24 #define VCPU_ID                         1
  25
  26 /* The memory slot index to track dirty pages */
  27 #define TEST_MEM_SLOT_INDEX             1
  28
  29 /* Default guest test memory offset, 1G */
  30 #define DEFAULT_GUEST_TEST_MEM          0x40000000
  31
  32 /* How many pages to dirty for each guest loop */
  33 #define TEST_PAGES_PER_LOOP             1024
  34
  35 /* How many host loops to run (one KVM_GET_DIRTY_LOG for each loop) */
  36 #define TEST_HOST_LOOP_N                32UL
  37
  38 /* Interval for each host loop (ms) */
  39 #define TEST_HOST_LOOP_INTERVAL         10UL
  40
  41 /*
  42  * Guest/Host shared variables. Ensure addr_gva2hva() and/or
  43  * sync_global_to/from_guest() are used when accessing from
  44  * the host. READ/WRITE_ONCE() should also be used with anything
  45  * that may change.
  46  */
  47 static uint64_t host_page_size;
  48 static uint64_t guest_page_size;
  49 static uint64_t guest_num_pages;
  50 static uint64_t random_array[TEST_PAGES_PER_LOOP];
  51 static uint64_t iteration;
  52
  53 /*
  54  * Guest physical memory offset of the testing memory slot.
  55  * This will be set to the topmost valid physical address minus
  56  * the test memory size.
  57  */
  58 static uint64_t guest_test_phys_mem;
  59
  60 /*
  61  * Guest virtual memory offset of the testing memory slot.
  62  * Must not conflict with identity mapped test code.
  63  */
  64 static uint64_t guest_test_virt_mem = DEFAULT_GUEST_TEST_MEM;
  65
  66 /*
  67  * Continuously write to the first 8 bytes of a random pages within
  68  * the testing memory region.
  69  */
  70 static void guest_code(void)
  71 {
  72         int i;
  73
  74         while (true) {
  75                 for (i = 0; i < TEST_PAGES_PER_LOOP; i++) {
  76                         uint64_t addr = guest_test_virt_mem;
  77                         addr += (READ_ONCE(random_array[i]) % guest_num_pages)
  78                                 * guest_page_size;
  79                         addr &= ~(host_page_size - 1);
  80                         *(uint64_t *)addr = READ_ONCE(iteration);
  81                 }
  82
  83                 /* Tell the host that we need more random numbers */
  84                 GUEST_SYNC(1);
  85         }
  86 }
  87
  88 /* Host variables */
  89 static bool host_quit;
  90
  91 /* Points to the test VM memory region on which we track dirty logs */
  92 static void *host_test_mem;
  93 static uint64_t host_num_pages;
  94
  95 /* For statistics only */
  96 static uint64_t host_dirty_count;
  97 static uint64_t host_clear_count;
  98 static uint64_t host_track_next_count;
  99
 100 /*
 101  * We use this bitmap to track some pages that should have its dirty
 102  * bit set in the _next_ iteration.  For example, if we detected the
 103  * page value changed to current iteration but at the same time the
 104  * page bit is cleared in the latest bitmap, then the system must
 105  * report that write in the next get dirty log call.
 106  */
 107 static unsigned long *host_bmap_track;
 108
 109 static void generate_random_array(uint64_t *guest_array, uint64_t size)
 110 {
 111         uint64_t i;
 112
 113         for (i = 0; i < size; i++)
 114                 guest_array[i] = random();
 115 }
 116
 117 static void *vcpu_worker(void *data)
 118 {
 119         int ret;
 120         struct kvm_vm *vm = data;
 121         uint64_t *guest_array;
 122         uint64_t pages_count = 0;
 123         struct kvm_run *run;
 124         struct ucall uc;
 125
 126         run = vcpu_state(vm, VCPU_ID);
 127
 128         guest_array = addr_gva2hva(vm, (vm_vaddr_t)random_array);
 129         generate_random_array(guest_array, TEST_PAGES_PER_LOOP);
 130
 131         while (!READ_ONCE(host_quit)) {
 132                 /* Let the guest dirty the random pages */
 133                 ret = _vcpu_run(vm, VCPU_ID);
 134                 if (get_ucall(vm, VCPU_ID, &uc) == UCALL_SYNC) {
 135                         pages_count += TEST_PAGES_PER_LOOP;
 136                         generate_random_array(guest_array, TEST_PAGES_PER_LOOP);
 137                 } else {
 138                         TEST_ASSERT(false,
 139                                     "Invalid guest sync status: "
 140                                     "exit_reason=%s\n",
 141                                     exit_reason_str(run->exit_reason));
 142                 }
 143         }
 144
 145         DEBUG("Dirtied %"PRIu64" pages\n", pages_count);
 146
 147         return NULL;
 148 }
 149
 150 static void vm_dirty_log_verify(unsigned long *bmap)
 151 {
 152         uint64_t page;
 153         uint64_t *value_ptr;
 154         uint64_t step = host_page_size >= guest_page_size ? 1 :
 155                                 guest_page_size / host_page_size;
 156
 157         for (page = 0; page < host_num_pages; page += step) {
 158                 value_ptr = host_test_mem + page * host_page_size;
 159
 160                 /* If this is a special page that we were tracking... */
 161                 if (test_and_clear_bit(page, host_bmap_track)) {
 162                         host_track_next_count++;
 163                         TEST_ASSERT(test_bit(page, bmap),
 164                                     "Page %"PRIu64" should have its dirty bit "
 165                                     "set in this iteration but it is missing",
 166                                     page);
 167                 }
 168
 169                 if (test_bit(page, bmap)) {
 170                         host_dirty_count++;
 171                         /*
 172                          * If the bit is set, the value written onto
 173                          * the corresponding page should be either the
 174                          * previous iteration number or the current one.
 175                          */
 176                         TEST_ASSERT(*value_ptr == iteration ||
 177                                     *value_ptr == iteration - 1,
 178                                     "Set page %"PRIu64" value %"PRIu64
 179                                     " incorrect (iteration=%"PRIu64")",
 180                                     page, *value_ptr, iteration);
 181                 } else {
 182                         host_clear_count++;
 183                         /*
 184                          * If cleared, the value written can be any
 185                          * value smaller or equals to the iteration
 186                          * number.  Note that the value can be exactly
 187                          * (iteration-1) if that write can happen
 188                          * like this:
 189                          *
 190                          * (1) increase loop count to "iteration-1"
 191                          * (2) write to page P happens (with value
 192                          *     "iteration-1")
 193                          * (3) get dirty log for "iteration-1"; we'll
 194                          *     see that page P bit is set (dirtied),
 195                          *     and not set the bit in host_bmap_track
 196                          * (4) increase loop count to "iteration"
 197                          *     (which is current iteration)
 198                          * (5) get dirty log for current iteration,
 199                          *     we'll see that page P is cleared, with
 200                          *     value "iteration-1".
 201                          */
 202                         TEST_ASSERT(*value_ptr <= iteration,
 203                                     "Clear page %"PRIu64" value %"PRIu64
 204                                     " incorrect (iteration=%"PRIu64")",
 205                                     page, *value_ptr, iteration);
 206                         if (*value_ptr == iteration) {
 207                                 /*
 208                                  * This page is _just_ modified; it
 209                                  * should report its dirtyness in the
 210                                  * next run
 211                                  */
 212                                 set_bit(page, host_bmap_track);
 213                         }
 214                 }
 215         }
 216 }
 217
 218 static struct kvm_vm *create_vm(enum vm_guest_mode mode, uint32_t vcpuid,
 219                                 uint64_t extra_mem_pages, void *guest_code,
 220                                 unsigned long type)
 221 {
 222         struct kvm_vm *vm;
 223         uint64_t extra_pg_pages = extra_mem_pages / 512 * 2;
 224
 225         vm = _vm_create(mode, DEFAULT_GUEST_PHY_PAGES + extra_pg_pages,
 226                         O_RDWR, type);
 227         kvm_vm_elf_load(vm, program_invocation_name, 0, 0);
 228 #ifdef __x86_64__
 229         vm_create_irqchip(vm);
 230 #endif
 231         vm_vcpu_add_default(vm, vcpuid, guest_code);
 232         return vm;
 233 }
 234
 235 static void run_test(enum vm_guest_mode mode, unsigned long iterations,
 236                      unsigned long interval, uint64_t phys_offset)
 237 {
 238         unsigned int guest_pa_bits, guest_page_shift;
 239         pthread_t vcpu_thread;
 240         struct kvm_vm *vm;
 241         uint64_t max_gfn;
 242         unsigned long *bmap;
 243         unsigned long type = 0;
 244
 245         switch (mode) {
 246         case VM_MODE_P52V48_4K:
 247                 guest_pa_bits = 52;
 248                 guest_page_shift = 12;
 249                 break;
 250         case VM_MODE_P52V48_64K:
 251                 guest_pa_bits = 52;
 252                 guest_page_shift = 16;
 253                 break;
 254         case VM_MODE_P48V48_4K:
 255                 guest_pa_bits = 48;
 256                 guest_page_shift = 12;
 257                 break;
 258         case VM_MODE_P48V48_64K:
 259                 guest_pa_bits = 48;
 260                 guest_page_shift = 16;
 261                 break;
 262         case VM_MODE_P40V48_4K:
 263                 guest_pa_bits = 40;
 264                 guest_page_shift = 12;
 265                 break;
 266         case VM_MODE_P40V48_64K:
 267                 guest_pa_bits = 40;
 268                 guest_page_shift = 16;
 269                 break;
 270         default:
 271                 TEST_ASSERT(false, "Unknown guest mode, mode: 0x%x", mode);
 272         }
 273
 274         DEBUG("Testing guest mode: %s\n", vm_guest_mode_string(mode));
 275
 276 #ifdef __x86_64__
 277         /*
 278          * FIXME
 279          * The x86_64 kvm selftests framework currently only supports a
 280          * single PML4 which restricts the number of physical address
 281          * bits we can change to 39.
 282          */
 283         guest_pa_bits = 39;
 284 #endif
 285 #ifdef __aarch64__
 286         if (guest_pa_bits != 40)
 287                 type = KVM_VM_TYPE_ARM_IPA_SIZE(guest_pa_bits);
 288 #endif
 289         max_gfn = (1ul << (guest_pa_bits - guest_page_shift)) - 1;
 290         guest_page_size = (1ul << guest_page_shift);
 291         /*
 292          * A little more than 1G of guest page sized pages.  Cover the
 293          * case where the size is not aligned to 64 pages.
 294          */
 295         guest_num_pages = (1ul << (30 - guest_page_shift)) + 3;
 296         host_page_size = getpagesize();
 297         host_num_pages = (guest_num_pages * guest_page_size) / host_page_size +
 298                          !!((guest_num_pages * guest_page_size) % host_page_size);
 299
 300         if (!phys_offset) {
 301                 guest_test_phys_mem = (max_gfn - guest_num_pages) * guest_page_size;
 302                 guest_test_phys_mem &= ~(host_page_size - 1);
 303         } else {
 304                 guest_test_phys_mem = phys_offset;
 305         }
 306
 307         DEBUG("guest physical test memory offset: 0x%lx\n", guest_test_phys_mem);
 308
 309         bmap = bitmap_alloc(host_num_pages);
 310         host_bmap_track = bitmap_alloc(host_num_pages);
 311
 312         vm = create_vm(mode, VCPU_ID, guest_num_pages, guest_code, type);
 313
 314 #ifdef USE_CLEAR_DIRTY_LOG
 315         struct kvm_enable_cap cap = {};
 316
 317         cap.cap = KVM_CAP_MANUAL_DIRTY_LOG_PROTECT;
 318         cap.args[0] = 1;
 319         vm_enable_cap(vm, &cap);
 320 #endif
 321
 322         /* Add an extra memory slot for testing dirty logging */
 323         vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS,
 324                                     guest_test_phys_mem,
 325                                     TEST_MEM_SLOT_INDEX,
 326                                     guest_num_pages,
 327                                     KVM_MEM_LOG_DIRTY_PAGES);
 328
 329         /* Do mapping for the dirty track memory slot */
 330         virt_map(vm, guest_test_virt_mem, guest_test_phys_mem,
 331                  guest_num_pages * guest_page_size, 0);
 332
 333         /* Cache the HVA pointer of the region */
 334         host_test_mem = addr_gpa2hva(vm, (vm_paddr_t)guest_test_phys_mem);
 335
 336 #ifdef __x86_64__
 337         vcpu_set_cpuid(vm, VCPU_ID, kvm_get_supported_cpuid());
 338 #endif
 339 #ifdef __aarch64__
 340         ucall_init(vm, UCALL_MMIO, NULL);
 341 #endif
 342
 343         /* Export the shared variables to the guest */
 344         sync_global_to_guest(vm, host_page_size);
 345         sync_global_to_guest(vm, guest_page_size);
 346         sync_global_to_guest(vm, guest_test_virt_mem);
 347         sync_global_to_guest(vm, guest_num_pages);
 348
 349         /* Start the iterations */
 350         iteration = 1;
 351         sync_global_to_guest(vm, iteration);
 352         host_quit = false;
 353         host_dirty_count = 0;
 354         host_clear_count = 0;
 355         host_track_next_count = 0;
 356
 357         pthread_create(&vcpu_thread, NULL, vcpu_worker, vm);
 358
 359         while (iteration < iterations) {
 360                 /* Give the vcpu thread some time to dirty some pages */
 361                 usleep(interval * 1000);
 362                 kvm_vm_get_dirty_log(vm, TEST_MEM_SLOT_INDEX, bmap);
 363 #ifdef USE_CLEAR_DIRTY_LOG
 364                 kvm_vm_clear_dirty_log(vm, TEST_MEM_SLOT_INDEX, bmap, 0,
 365                                        host_num_pages);
 366 #endif
 367                 vm_dirty_log_verify(bmap);
 368                 iteration++;
 369                 sync_global_to_guest(vm, iteration);
 370         }
 371
 372         /* Tell the vcpu thread to quit */
 373         host_quit = true;
 374         pthread_join(vcpu_thread, NULL);
 375
 376         DEBUG("Total bits checked: dirty (%"PRIu64"), clear (%"PRIu64"), "
 377               "track_next (%"PRIu64")\n", host_dirty_count, host_clear_count,
 378               host_track_next_count);
 379
 380         free(bmap);
 381         free(host_bmap_track);
 382         ucall_uninit(vm);
 383         kvm_vm_free(vm);
 384 }
 385
 386 struct vm_guest_mode_params {
 387         bool supported;
 388         bool enabled;
 389 };
 390 struct vm_guest_mode_params vm_guest_mode_params[NUM_VM_MODES];
 391
 392 #define vm_guest_mode_params_init(mode, supported, enabled)                                     \
 393 ({                                                                                              \
 394         vm_guest_mode_params[mode] = (struct vm_guest_mode_params){ supported, enabled };       \
 395 })
 396
 397 static void help(char *name)
 398 {
 399         int i;
 400
 401         puts("");
 402         printf("usage: %s [-h] [-i iterations] [-I interval] "
 403                "[-p offset] [-m mode]\n", name);
 404         puts("");
 405         printf(" -i: specify iteration counts (default: %"PRIu64")\n",
 406                TEST_HOST_LOOP_N);
 407         printf(" -I: specify interval in ms (default: %"PRIu64" ms)\n",
 408                TEST_HOST_LOOP_INTERVAL);
 409         printf(" -p: specify guest physical test memory offset\n"
 410                "     Warning: a low offset can conflict with the loaded test code.\n");
 411         printf(" -m: specify the guest mode ID to test "
 412                "(default: test all supported modes)\n"
 413                "     This option may be used multiple times.\n"
 414                "     Guest mode IDs:\n");
 415         for (i = 0; i < NUM_VM_MODES; ++i) {
 416                 printf("         %d:    %s%s\n", i, vm_guest_mode_string(i),
 417                        vm_guest_mode_params[i].supported ? " (supported)" : "");
 418         }
 419         puts("");
 420         exit(0);
 421 }
 422
 423 int main(int argc, char *argv[])
 424 {
 425         unsigned long iterations = TEST_HOST_LOOP_N;
 426         unsigned long interval = TEST_HOST_LOOP_INTERVAL;
 427         bool mode_selected = false;
 428         uint64_t phys_offset = 0;
 429         unsigned int mode, host_ipa_limit;
 430         int opt, i;
 431
 432 #ifdef USE_CLEAR_DIRTY_LOG
 433         if (!kvm_check_cap(KVM_CAP_MANUAL_DIRTY_LOG_PROTECT)) {
 434                 fprintf(stderr, "KVM_CLEAR_DIRTY_LOG not available, skipping tests\n");
 435                 exit(KSFT_SKIP);
 436         }
 437 #endif
 438
 439 #ifdef __x86_64__
 440         vm_guest_mode_params_init(VM_MODE_P52V48_4K, true, true);
 441 #endif
 442 #ifdef __aarch64__
 443         vm_guest_mode_params_init(VM_MODE_P40V48_4K, true, true);
 444         vm_guest_mode_params_init(VM_MODE_P40V48_64K, true, true);
 445
 446         host_ipa_limit = kvm_check_cap(KVM_CAP_ARM_VM_IPA_SIZE);
 447         if (host_ipa_limit >= 52)
 448                 vm_guest_mode_params_init(VM_MODE_P52V48_64K, true, true);
 449         if (host_ipa_limit >= 48) {
 450                 vm_guest_mode_params_init(VM_MODE_P48V48_4K, true, true);
 451                 vm_guest_mode_params_init(VM_MODE_P48V48_64K, true, true);
 452         }
 453 #endif
 454
 455         while ((opt = getopt(argc, argv, "hi:I:p:m:")) != -1) {
 456                 switch (opt) {
 457                 case 'i':
 458                         iterations = strtol(optarg, NULL, 10);
 459                         break;
 460                 case 'I':
 461                         interval = strtol(optarg, NULL, 10);
 462                         break;
 463                 case 'p':
 464                         phys_offset = strtoull(optarg, NULL, 0);
 465                         break;
 466                 case 'm':
 467                         if (!mode_selected) {
 468                                 for (i = 0; i < NUM_VM_MODES; ++i)
 469                                         vm_guest_mode_params[i].enabled = false;
 470                                 mode_selected = true;
 471                         }
 472                         mode = strtoul(optarg, NULL, 10);
 473                         TEST_ASSERT(mode < NUM_VM_MODES,
 474                                     "Guest mode ID %d too big", mode);
 475                         vm_guest_mode_params[mode].enabled = true;
 476                         break;
 477                 case 'h':
 478                 default:
 479                         help(argv[0]);
 480                         break;
 481                 }
 482         }
 483
 484         TEST_ASSERT(iterations > 2, "Iterations must be greater than two");
 485         TEST_ASSERT(interval > 0, "Interval must be greater than zero");
 486
 487         DEBUG("Test iterations: %"PRIu64", interval: %"PRIu64" (ms)\n",
 488               iterations, interval);
 489
 490         srandom(time(0));
 491
 492         for (i = 0; i < NUM_VM_MODES; ++i) {
 493                 if (!vm_guest_mode_params[i].enabled)
 494                         continue;
 495                 TEST_ASSERT(vm_guest_mode_params[i].supported,
 496                             "Guest mode ID %d (%s) not supported.",
 497                             i, vm_guest_mode_string(i));
 498                 run_test(i, iterations, interval, phys_offset);
 499         }
 500
 501         return 0;
 502 }