root/tools/testing/selftests/kvm/dirty_log_test.c

DEFINITIONS

1. guest_code
2. generate_random_array
3. vcpu_worker
4. vm_dirty_log_verify
5. create_vm
6. run_test
7. help
8. main

   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 VCPU_ID                         1
  23 
  24 /* The memory slot index to track dirty pages */
  25 #define TEST_MEM_SLOT_INDEX             1
  26 
  27 /* Default guest test virtual memory offset */
  28 #define DEFAULT_GUEST_TEST_MEM          0xc0000000
  29 
  30 /* How many pages to dirty for each guest loop */
  31 #define TEST_PAGES_PER_LOOP             1024
  32 
  33 /* How many host loops to run (one KVM_GET_DIRTY_LOG for each loop) */
  34 #define TEST_HOST_LOOP_N                32UL
  35 
  36 /* Interval for each host loop (ms) */
  37 #define TEST_HOST_LOOP_INTERVAL         10UL
  38 
  39 /* Dirty bitmaps are always little endian, so we need to swap on big endian */
  40 #if defined(__s390x__)
  41 # define BITOP_LE_SWIZZLE       ((BITS_PER_LONG-1) & ~0x7)
  42 # define test_bit_le(nr, addr) \
  43         test_bit((nr) ^ BITOP_LE_SWIZZLE, addr)
  44 # define set_bit_le(nr, addr) \
  45         set_bit((nr) ^ BITOP_LE_SWIZZLE, addr)
  46 # define clear_bit_le(nr, addr) \
  47         clear_bit((nr) ^ BITOP_LE_SWIZZLE, addr)
  48 # define test_and_set_bit_le(nr, addr) \
  49         test_and_set_bit((nr) ^ BITOP_LE_SWIZZLE, addr)
  50 # define test_and_clear_bit_le(nr, addr) \
  51         test_and_clear_bit((nr) ^ BITOP_LE_SWIZZLE, addr)
  52 #else
  53 # define test_bit_le            test_bit
  54 # define set_bit_le             set_bit
  55 # define clear_bit_le           clear_bit
  56 # define test_and_set_bit_le    test_and_set_bit
  57 # define test_and_clear_bit_le  test_and_clear_bit
  58 #endif
  59 
  60 /*
  61  * Guest/Host shared variables. Ensure addr_gva2hva() and/or
  62  * sync_global_to/from_guest() are used when accessing from
  63  * the host. READ/WRITE_ONCE() should also be used with anything
  64  * that may change.
  65  */
  66 static uint64_t host_page_size;
  67 static uint64_t guest_page_size;
  68 static uint64_t guest_num_pages;
  69 static uint64_t random_array[TEST_PAGES_PER_LOOP];
  70 static uint64_t iteration;
  71 
  72 /*
  73  * Guest physical memory offset of the testing memory slot.
  74  * This will be set to the topmost valid physical address minus
  75  * the test memory size.
  76  */
  77 static uint64_t guest_test_phys_mem;
  78 
  79 /*
  80  * Guest virtual memory offset of the testing memory slot.
  81  * Must not conflict with identity mapped test code.
  82  */
  83 static uint64_t guest_test_virt_mem = DEFAULT_GUEST_TEST_MEM;
  84 
  85 /*
  86  * Continuously write to the first 8 bytes of a random pages within
  87  * the testing memory region.
  88  */
  89 static void guest_code(void)
  90 {
  91         uint64_t addr;
  92         int i;
  93 
  94         /*
  95          * On s390x, all pages of a 1M segment are initially marked as dirty
  96          * when a page of the segment is written to for the very first time.
  97          * To compensate this specialty in this test, we need to touch all
  98          * pages during the first iteration.
  99          */
 100         for (i = 0; i < guest_num_pages; i++) {
 101                 addr = guest_test_virt_mem + i * guest_page_size;
 102                 *(uint64_t *)addr = READ_ONCE(iteration);
 103         }
 104 
 105         while (true) {
 106                 for (i = 0; i < TEST_PAGES_PER_LOOP; i++) {
 107                         addr = guest_test_virt_mem;
 108                         addr += (READ_ONCE(random_array[i]) % guest_num_pages)
 109                                 * guest_page_size;
 110                         addr &= ~(host_page_size - 1);
 111                         *(uint64_t *)addr = READ_ONCE(iteration);
 112                 }
 113 
 114                 /* Tell the host that we need more random numbers */
 115                 GUEST_SYNC(1);
 116         }
 117 }
 118 
 119 /* Host variables */
 120 static bool host_quit;
 121 
 122 /* Points to the test VM memory region on which we track dirty logs */
 123 static void *host_test_mem;
 124 static uint64_t host_num_pages;
 125 
 126 /* For statistics only */
 127 static uint64_t host_dirty_count;
 128 static uint64_t host_clear_count;
 129 static uint64_t host_track_next_count;
 130 
 131 /*
 132  * We use this bitmap to track some pages that should have its dirty
 133  * bit set in the _next_ iteration.  For example, if we detected the
 134  * page value changed to current iteration but at the same time the
 135  * page bit is cleared in the latest bitmap, then the system must
 136  * report that write in the next get dirty log call.
 137  */
 138 static unsigned long *host_bmap_track;
 139 
 140 static void generate_random_array(uint64_t *guest_array, uint64_t size)
 141 {
 142         uint64_t i;
 143 
 144         for (i = 0; i < size; i++)
 145                 guest_array[i] = random();
 146 }
 147 
 148 static void *vcpu_worker(void *data)
 149 {
 150         int ret;
 151         struct kvm_vm *vm = data;
 152         uint64_t *guest_array;
 153         uint64_t pages_count = 0;
 154         struct kvm_run *run;
 155 
 156         run = vcpu_state(vm, VCPU_ID);
 157 
 158         guest_array = addr_gva2hva(vm, (vm_vaddr_t)random_array);
 159         generate_random_array(guest_array, TEST_PAGES_PER_LOOP);
 160 
 161         while (!READ_ONCE(host_quit)) {
 162                 /* Let the guest dirty the random pages */
 163                 ret = _vcpu_run(vm, VCPU_ID);
 164                 TEST_ASSERT(ret == 0, "vcpu_run failed: %d\n", ret);
 165                 if (get_ucall(vm, VCPU_ID, NULL) == UCALL_SYNC) {
 166                         pages_count += TEST_PAGES_PER_LOOP;
 167                         generate_random_array(guest_array, TEST_PAGES_PER_LOOP);
 168                 } else {
 169                         TEST_ASSERT(false,
 170                                     "Invalid guest sync status: "
 171                                     "exit_reason=%s\n",
 172                                     exit_reason_str(run->exit_reason));
 173                 }
 174         }
 175 
 176         DEBUG("Dirtied %"PRIu64" pages\n", pages_count);
 177 
 178         return NULL;
 179 }
 180 
 181 static void vm_dirty_log_verify(unsigned long *bmap)
 182 {
 183         uint64_t page;
 184         uint64_t *value_ptr;
 185         uint64_t step = host_page_size >= guest_page_size ? 1 :
 186                                 guest_page_size / host_page_size;
 187 
 188         for (page = 0; page < host_num_pages; page += step) {
 189                 value_ptr = host_test_mem + page * host_page_size;
 190 
 191                 /* If this is a special page that we were tracking... */
 192                 if (test_and_clear_bit_le(page, host_bmap_track)) {
 193                         host_track_next_count++;
 194                         TEST_ASSERT(test_bit_le(page, bmap),
 195                                     "Page %"PRIu64" should have its dirty bit "
 196                                     "set in this iteration but it is missing",
 197                                     page);
 198                 }
 199 
 200                 if (test_bit_le(page, bmap)) {
 201                         host_dirty_count++;
 202                         /*
 203                          * If the bit is set, the value written onto
 204                          * the corresponding page should be either the
 205                          * previous iteration number or the current one.
 206                          */
 207                         TEST_ASSERT(*value_ptr == iteration ||
 208                                     *value_ptr == iteration - 1,
 209                                     "Set page %"PRIu64" value %"PRIu64
 210                                     " incorrect (iteration=%"PRIu64")",
 211                                     page, *value_ptr, iteration);
 212                 } else {
 213                         host_clear_count++;
 214                         /*
 215                          * If cleared, the value written can be any
 216                          * value smaller or equals to the iteration
 217                          * number.  Note that the value can be exactly
 218                          * (iteration-1) if that write can happen
 219                          * like this:
 220                          *
 221                          * (1) increase loop count to "iteration-1"
 222                          * (2) write to page P happens (with value
 223                          *     "iteration-1")
 224                          * (3) get dirty log for "iteration-1"; we'll
 225                          *     see that page P bit is set (dirtied),
 226                          *     and not set the bit in host_bmap_track
 227                          * (4) increase loop count to "iteration"
 228                          *     (which is current iteration)
 229                          * (5) get dirty log for current iteration,
 230                          *     we'll see that page P is cleared, with
 231                          *     value "iteration-1".
 232                          */
 233                         TEST_ASSERT(*value_ptr <= iteration,
 234                                     "Clear page %"PRIu64" value %"PRIu64
 235                                     " incorrect (iteration=%"PRIu64")",
 236                                     page, *value_ptr, iteration);
 237                         if (*value_ptr == iteration) {
 238                                 /*
 239                                  * This page is _just_ modified; it
 240                                  * should report its dirtyness in the
 241                                  * next run
 242                                  */
 243                                 set_bit_le(page, host_bmap_track);
 244                         }
 245                 }
 246         }
 247 }
 248 
 249 static struct kvm_vm *create_vm(enum vm_guest_mode mode, uint32_t vcpuid,
 250                                 uint64_t extra_mem_pages, void *guest_code)
 251 {
 252         struct kvm_vm *vm;
 253         uint64_t extra_pg_pages = extra_mem_pages / 512 * 2;
 254 
 255         vm = _vm_create(mode, DEFAULT_GUEST_PHY_PAGES + extra_pg_pages, O_RDWR);
 256         kvm_vm_elf_load(vm, program_invocation_name, 0, 0);
 257 #ifdef __x86_64__
 258         vm_create_irqchip(vm);
 259 #endif
 260         vm_vcpu_add_default(vm, vcpuid, guest_code);
 261         return vm;
 262 }
 263 
 264 #define DIRTY_MEM_BITS 30 /* 1G */
 265 #define PAGE_SHIFT_4K  12
 266 
 267 static void run_test(enum vm_guest_mode mode, unsigned long iterations,
 268                      unsigned long interval, uint64_t phys_offset)
 269 {
 270         pthread_t vcpu_thread;
 271         struct kvm_vm *vm;
 272         unsigned long *bmap;
 273 
 274         /*
 275          * We reserve page table for 2 times of extra dirty mem which
 276          * will definitely cover the original (1G+) test range.  Here
 277          * we do the calculation with 4K page size which is the
 278          * smallest so the page number will be enough for all archs
 279          * (e.g., 64K page size guest will need even less memory for
 280          * page tables).
 281          */
 282         vm = create_vm(mode, VCPU_ID,
 283                        2ul << (DIRTY_MEM_BITS - PAGE_SHIFT_4K),
 284                        guest_code);
 285 
 286         guest_page_size = vm_get_page_size(vm);
 287         /*
 288          * A little more than 1G of guest page sized pages.  Cover the
 289          * case where the size is not aligned to 64 pages.
 290          */
 291         guest_num_pages = (1ul << (DIRTY_MEM_BITS -
 292                                    vm_get_page_shift(vm))) + 16;
 293 #ifdef __s390x__
 294         /* Round up to multiple of 1M (segment size) */
 295         guest_num_pages = (guest_num_pages + 0xff) & ~0xffUL;
 296 #endif
 297         host_page_size = getpagesize();
 298         host_num_pages = (guest_num_pages * guest_page_size) / host_page_size +
 299                          !!((guest_num_pages * guest_page_size) % host_page_size);
 300 
 301         if (!phys_offset) {
 302                 guest_test_phys_mem = (vm_get_max_gfn(vm) -
 303                                        guest_num_pages) * guest_page_size;
 304                 guest_test_phys_mem &= ~(host_page_size - 1);
 305         } else {
 306                 guest_test_phys_mem = phys_offset;
 307         }
 308 
 309 #ifdef __s390x__
 310         /* Align to 1M (segment size) */
 311         guest_test_phys_mem &= ~((1 << 20) - 1);
 312 #endif
 313 
 314         DEBUG("guest physical test memory offset: 0x%lx\n", guest_test_phys_mem);
 315 
 316         bmap = bitmap_alloc(host_num_pages);
 317         host_bmap_track = bitmap_alloc(host_num_pages);
 318 
 319 #ifdef USE_CLEAR_DIRTY_LOG
 320         struct kvm_enable_cap cap = {};
 321 
 322         cap.cap = KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2;
 323         cap.args[0] = 1;
 324         vm_enable_cap(vm, &cap);
 325 #endif
 326 
 327         /* Add an extra memory slot for testing dirty logging */
 328         vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS,
 329                                     guest_test_phys_mem,
 330                                     TEST_MEM_SLOT_INDEX,
 331                                     guest_num_pages,
 332                                     KVM_MEM_LOG_DIRTY_PAGES);
 333 
 334         /* Do mapping for the dirty track memory slot */
 335         virt_map(vm, guest_test_virt_mem, guest_test_phys_mem,
 336                  guest_num_pages * guest_page_size, 0);
 337 
 338         /* Cache the HVA pointer of the region */
 339         host_test_mem = addr_gpa2hva(vm, (vm_paddr_t)guest_test_phys_mem);
 340 
 341 #ifdef __x86_64__
 342         vcpu_set_cpuid(vm, VCPU_ID, kvm_get_supported_cpuid());
 343 #endif
 344 #ifdef __aarch64__
 345         ucall_init(vm, NULL);
 346 #endif
 347 
 348         /* Export the shared variables to the guest */
 349         sync_global_to_guest(vm, host_page_size);
 350         sync_global_to_guest(vm, guest_page_size);
 351         sync_global_to_guest(vm, guest_test_virt_mem);
 352         sync_global_to_guest(vm, guest_num_pages);
 353 
 354         /* Start the iterations */
 355         iteration = 1;
 356         sync_global_to_guest(vm, iteration);
 357         host_quit = false;
 358         host_dirty_count = 0;
 359         host_clear_count = 0;
 360         host_track_next_count = 0;
 361 
 362         pthread_create(&vcpu_thread, NULL, vcpu_worker, vm);
 363 
 364         while (iteration < iterations) {
 365                 /* Give the vcpu thread some time to dirty some pages */
 366                 usleep(interval * 1000);
 367                 kvm_vm_get_dirty_log(vm, TEST_MEM_SLOT_INDEX, bmap);
 368 #ifdef USE_CLEAR_DIRTY_LOG
 369                 kvm_vm_clear_dirty_log(vm, TEST_MEM_SLOT_INDEX, bmap, 0,
 370                                        host_num_pages);
 371 #endif
 372                 vm_dirty_log_verify(bmap);
 373                 iteration++;
 374                 sync_global_to_guest(vm, iteration);
 375         }
 376 
 377         /* Tell the vcpu thread to quit */
 378         host_quit = true;
 379         pthread_join(vcpu_thread, NULL);
 380 
 381         DEBUG("Total bits checked: dirty (%"PRIu64"), clear (%"PRIu64"), "
 382               "track_next (%"PRIu64")\n", host_dirty_count, host_clear_count,
 383               host_track_next_count);
 384 
 385         free(bmap);
 386         free(host_bmap_track);
 387         ucall_uninit(vm);
 388         kvm_vm_free(vm);
 389 }
 390 
 391 struct vm_guest_mode_params {
 392         bool supported;
 393         bool enabled;
 394 };
 395 struct vm_guest_mode_params vm_guest_mode_params[NUM_VM_MODES];
 396 
 397 #define vm_guest_mode_params_init(mode, supported, enabled)                                     \
 398 ({                                                                                              \
 399         vm_guest_mode_params[mode] = (struct vm_guest_mode_params){ supported, enabled };       \
 400 })
 401 
 402 static void help(char *name)
 403 {
 404         int i;
 405 
 406         puts("");
 407         printf("usage: %s [-h] [-i iterations] [-I interval] "
 408                "[-p offset] [-m mode]\n", name);
 409         puts("");
 410         printf(" -i: specify iteration counts (default: %"PRIu64")\n",
 411                TEST_HOST_LOOP_N);
 412         printf(" -I: specify interval in ms (default: %"PRIu64" ms)\n",
 413                TEST_HOST_LOOP_INTERVAL);
 414         printf(" -p: specify guest physical test memory offset\n"
 415                "     Warning: a low offset can conflict with the loaded test code.\n");
 416         printf(" -m: specify the guest mode ID to test "
 417                "(default: test all supported modes)\n"
 418                "     This option may be used multiple times.\n"
 419                "     Guest mode IDs:\n");
 420         for (i = 0; i < NUM_VM_MODES; ++i) {
 421                 printf("         %d:    %s%s\n", i, vm_guest_mode_string(i),
 422                        vm_guest_mode_params[i].supported ? " (supported)" : "");
 423         }
 424         puts("");
 425         exit(0);
 426 }
 427 
 428 int main(int argc, char *argv[])
 429 {
 430         unsigned long iterations = TEST_HOST_LOOP_N;
 431         unsigned long interval = TEST_HOST_LOOP_INTERVAL;
 432         bool mode_selected = false;
 433         uint64_t phys_offset = 0;
 434         unsigned int mode;
 435         int opt, i;
 436 #ifdef __aarch64__
 437         unsigned int host_ipa_limit;
 438 #endif
 439 
 440 #ifdef USE_CLEAR_DIRTY_LOG
 441         if (!kvm_check_cap(KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2)) {
 442                 fprintf(stderr, "KVM_CLEAR_DIRTY_LOG not available, skipping tests\n");
 443                 exit(KSFT_SKIP);
 444         }
 445 #endif
 446 
 447 #ifdef __x86_64__
 448         vm_guest_mode_params_init(VM_MODE_PXXV48_4K, true, true);
 449 #endif
 450 #ifdef __aarch64__
 451         vm_guest_mode_params_init(VM_MODE_P40V48_4K, true, true);
 452         vm_guest_mode_params_init(VM_MODE_P40V48_64K, true, true);
 453 
 454         host_ipa_limit = kvm_check_cap(KVM_CAP_ARM_VM_IPA_SIZE);
 455         if (host_ipa_limit >= 52)
 456                 vm_guest_mode_params_init(VM_MODE_P52V48_64K, true, true);
 457         if (host_ipa_limit >= 48) {
 458                 vm_guest_mode_params_init(VM_MODE_P48V48_4K, true, true);
 459                 vm_guest_mode_params_init(VM_MODE_P48V48_64K, true, true);
 460         }
 461 #endif
 462 #ifdef __s390x__
 463         vm_guest_mode_params_init(VM_MODE_P40V48_4K, true, true);
 464 #endif
 465 
 466         while ((opt = getopt(argc, argv, "hi:I:p:m:")) != -1) {
 467                 switch (opt) {
 468                 case 'i':
 469                         iterations = strtol(optarg, NULL, 10);
 470                         break;
 471                 case 'I':
 472                         interval = strtol(optarg, NULL, 10);
 473                         break;
 474                 case 'p':
 475                         phys_offset = strtoull(optarg, NULL, 0);
 476                         break;
 477                 case 'm':
 478                         if (!mode_selected) {
 479                                 for (i = 0; i < NUM_VM_MODES; ++i)
 480                                         vm_guest_mode_params[i].enabled = false;
 481                                 mode_selected = true;
 482                         }
 483                         mode = strtoul(optarg, NULL, 10);
 484                         TEST_ASSERT(mode < NUM_VM_MODES,
 485                                     "Guest mode ID %d too big", mode);
 486                         vm_guest_mode_params[mode].enabled = true;
 487                         break;
 488                 case 'h':
 489                 default:
 490                         help(argv[0]);
 491                         break;
 492                 }
 493         }
 494 
 495         TEST_ASSERT(iterations > 2, "Iterations must be greater than two");
 496         TEST_ASSERT(interval > 0, "Interval must be greater than zero");
 497 
 498         DEBUG("Test iterations: %"PRIu64", interval: %"PRIu64" (ms)\n",
 499               iterations, interval);
 500 
 501         srandom(time(0));
 502 
 503         for (i = 0; i < NUM_VM_MODES; ++i) {
 504                 if (!vm_guest_mode_params[i].enabled)
 505                         continue;
 506                 TEST_ASSERT(vm_guest_mode_params[i].supported,
 507                             "Guest mode ID %d (%s) not supported.",
 508                             i, vm_guest_mode_string(i));
 509                 run_test(i, iterations, interval, phys_offset);
 510         }
 511 
 512         return 0;
 513 }