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                32
  37
  38 /* Interval for each host loop (ms) */
  39 #define TEST_HOST_LOOP_INTERVAL         10
  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  * GPA offset of the testing memory slot. Must be bigger than
  55  * DEFAULT_GUEST_PHY_PAGES.
  56  */
  57 static uint64_t guest_test_mem = DEFAULT_GUEST_TEST_MEM;
  58
  59 /*
  60  * Continuously write to the first 8 bytes of a random pages within
  61  * the testing memory region.
  62  */
  63 static void guest_code(void)
  64 {
  65         int i;
  66
  67         while (true) {
  68                 for (i = 0; i < TEST_PAGES_PER_LOOP; i++) {
  69                         uint64_t addr = guest_test_mem;
  70                         addr += (READ_ONCE(random_array[i]) % guest_num_pages)
  71                                 * guest_page_size;
  72                         addr &= ~(host_page_size - 1);
  73                         *(uint64_t *)addr = READ_ONCE(iteration);
  74                 }
  75
  76                 /* Tell the host that we need more random numbers */
  77                 GUEST_SYNC(1);
  78         }
  79 }
  80
  81 /* Host variables */
  82 static bool host_quit;
  83
  84 /* Points to the test VM memory region on which we track dirty logs */
  85 static void *host_test_mem;
  86 static uint64_t host_num_pages;
  87
  88 /* For statistics only */
  89 static uint64_t host_dirty_count;
  90 static uint64_t host_clear_count;
  91 static uint64_t host_track_next_count;
  92
  93 /*
  94  * We use this bitmap to track some pages that should have its dirty
  95  * bit set in the _next_ iteration.  For example, if we detected the
  96  * page value changed to current iteration but at the same time the
  97  * page bit is cleared in the latest bitmap, then the system must
  98  * report that write in the next get dirty log call.
  99  */
 100 static unsigned long *host_bmap_track;
 101
 102 static void generate_random_array(uint64_t *guest_array, uint64_t size)
 103 {
 104         uint64_t i;
 105
 106         for (i = 0; i < size; i++)
 107                 guest_array[i] = random();
 108 }
 109
 110 static void *vcpu_worker(void *data)
 111 {
 112         int ret;
 113         struct kvm_vm *vm = data;
 114         uint64_t *guest_array;
 115         uint64_t pages_count = 0;
 116         struct kvm_run *run;
 117         struct ucall uc;
 118
 119         run = vcpu_state(vm, VCPU_ID);
 120
 121         guest_array = addr_gva2hva(vm, (vm_vaddr_t)random_array);
 122         generate_random_array(guest_array, TEST_PAGES_PER_LOOP);
 123
 124         while (!READ_ONCE(host_quit)) {
 125                 /* Let the guest dirty the random pages */
 126                 ret = _vcpu_run(vm, VCPU_ID);
 127                 if (get_ucall(vm, VCPU_ID, &uc) == UCALL_SYNC) {
 128                         pages_count += TEST_PAGES_PER_LOOP;
 129                         generate_random_array(guest_array, TEST_PAGES_PER_LOOP);
 130                 } else {
 131                         TEST_ASSERT(false,
 132                                     "Invalid guest sync status: "
 133                                     "exit_reason=%s\n",
 134                                     exit_reason_str(run->exit_reason));
 135                 }
 136         }
 137
 138         DEBUG("Dirtied %"PRIu64" pages\n", pages_count);
 139
 140         return NULL;
 141 }
 142
 143 static void vm_dirty_log_verify(unsigned long *bmap)
 144 {
 145         uint64_t page;
 146         uint64_t *value_ptr;
 147         uint64_t step = host_page_size >= guest_page_size ? 1 :
 148                                 guest_page_size / host_page_size;
 149
 150         for (page = 0; page < host_num_pages; page += step) {
 151                 value_ptr = host_test_mem + page * host_page_size;
 152
 153                 /* If this is a special page that we were tracking... */
 154                 if (test_and_clear_bit(page, host_bmap_track)) {
 155                         host_track_next_count++;
 156                         TEST_ASSERT(test_bit(page, bmap),
 157                                     "Page %"PRIu64" should have its dirty bit "
 158                                     "set in this iteration but it is missing",
 159                                     page);
 160                 }
 161
 162                 if (test_bit(page, bmap)) {
 163                         host_dirty_count++;
 164                         /*
 165                          * If the bit is set, the value written onto
 166                          * the corresponding page should be either the
 167                          * previous iteration number or the current one.
 168                          */
 169                         TEST_ASSERT(*value_ptr == iteration ||
 170                                     *value_ptr == iteration - 1,
 171                                     "Set page %"PRIu64" value %"PRIu64
 172                                     " incorrect (iteration=%"PRIu64")",
 173                                     page, *value_ptr, iteration);
 174                 } else {
 175                         host_clear_count++;
 176                         /*
 177                          * If cleared, the value written can be any
 178                          * value smaller or equals to the iteration
 179                          * number.  Note that the value can be exactly
 180                          * (iteration-1) if that write can happen
 181                          * like this:
 182                          *
 183                          * (1) increase loop count to "iteration-1"
 184                          * (2) write to page P happens (with value
 185                          *     "iteration-1")
 186                          * (3) get dirty log for "iteration-1"; we'll
 187                          *     see that page P bit is set (dirtied),
 188                          *     and not set the bit in host_bmap_track
 189                          * (4) increase loop count to "iteration"
 190                          *     (which is current iteration)
 191                          * (5) get dirty log for current iteration,
 192                          *     we'll see that page P is cleared, with
 193                          *     value "iteration-1".
 194                          */
 195                         TEST_ASSERT(*value_ptr <= iteration,
 196                                     "Clear page %"PRIu64" value %"PRIu64
 197                                     " incorrect (iteration=%"PRIu64")",
 198                                     page, *value_ptr, iteration);
 199                         if (*value_ptr == iteration) {
 200                                 /*
 201                                  * This page is _just_ modified; it
 202                                  * should report its dirtyness in the
 203                                  * next run
 204                                  */
 205                                 set_bit(page, host_bmap_track);
 206                         }
 207                 }
 208         }
 209 }
 210
 211 static struct kvm_vm *create_vm(enum vm_guest_mode mode, uint32_t vcpuid,
 212                                 uint64_t extra_mem_pages, void *guest_code)
 213 {
 214         struct kvm_vm *vm;
 215         uint64_t extra_pg_pages = extra_mem_pages / 512 * 2;
 216
 217         vm = vm_create(mode, DEFAULT_GUEST_PHY_PAGES + extra_pg_pages, O_RDWR);
 218         kvm_vm_elf_load(vm, program_invocation_name, 0, 0);
 219 #ifdef __x86_64__
 220         vm_create_irqchip(vm);
 221 #endif
 222         vm_vcpu_add_default(vm, vcpuid, guest_code);
 223         return vm;
 224 }
 225
 226 static void run_test(enum vm_guest_mode mode, unsigned long iterations,
 227                      unsigned long interval, bool top_offset)
 228 {
 229         unsigned int guest_pa_bits, guest_page_shift;
 230         pthread_t vcpu_thread;
 231         struct kvm_vm *vm;
 232         uint64_t max_gfn;
 233         unsigned long *bmap;
 234
 235         switch (mode) {
 236         case VM_MODE_P52V48_4K:
 237                 guest_pa_bits = 52;
 238                 guest_page_shift = 12;
 239                 break;
 240         case VM_MODE_P52V48_64K:
 241                 guest_pa_bits = 52;
 242                 guest_page_shift = 16;
 243                 break;
 244         case VM_MODE_P40V48_4K:
 245                 guest_pa_bits = 40;
 246                 guest_page_shift = 12;
 247                 break;
 248         case VM_MODE_P40V48_64K:
 249                 guest_pa_bits = 40;
 250                 guest_page_shift = 16;
 251                 break;
 252         default:
 253                 TEST_ASSERT(false, "Unknown guest mode, mode: 0x%x", mode);
 254         }
 255
 256         DEBUG("Testing guest mode: %s\n", vm_guest_mode_string(mode));
 257
 258         max_gfn = (1ul << (guest_pa_bits - guest_page_shift)) - 1;
 259         guest_page_size = (1ul << guest_page_shift);
 260         /* 1G of guest page sized pages */
 261         guest_num_pages = (1ul << (30 - guest_page_shift));
 262         host_page_size = getpagesize();
 263         host_num_pages = (guest_num_pages * guest_page_size) / host_page_size +
 264                          !!((guest_num_pages * guest_page_size) % host_page_size);
 265
 266         if (top_offset) {
 267                 guest_test_mem = (max_gfn - guest_num_pages) * guest_page_size;
 268                 guest_test_mem &= ~(host_page_size - 1);
 269         }
 270
 271         DEBUG("guest test mem offset: 0x%lx\n", guest_test_mem);
 272
 273         bmap = bitmap_alloc(host_num_pages);
 274         host_bmap_track = bitmap_alloc(host_num_pages);
 275
 276         vm = create_vm(mode, VCPU_ID, guest_num_pages, guest_code);
 277
 278         /* Add an extra memory slot for testing dirty logging */
 279         vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS,
 280                                     guest_test_mem,
 281                                     TEST_MEM_SLOT_INDEX,
 282                                     guest_num_pages,
 283                                     KVM_MEM_LOG_DIRTY_PAGES);
 284
 285         /* Do 1:1 mapping for the dirty track memory slot */
 286         virt_map(vm, guest_test_mem, guest_test_mem,
 287                  guest_num_pages * guest_page_size, 0);
 288
 289         /* Cache the HVA pointer of the region */
 290         host_test_mem = addr_gpa2hva(vm, (vm_paddr_t)guest_test_mem);
 291
 292 #ifdef __x86_64__
 293         vcpu_set_cpuid(vm, VCPU_ID, kvm_get_supported_cpuid());
 294 #endif
 295 #ifdef __aarch64__
 296         ucall_init(vm, UCALL_MMIO, NULL);
 297 #endif
 298
 299         /* Export the shared variables to the guest */
 300         sync_global_to_guest(vm, host_page_size);
 301         sync_global_to_guest(vm, guest_page_size);
 302         sync_global_to_guest(vm, guest_test_mem);
 303         sync_global_to_guest(vm, guest_num_pages);
 304
 305         /* Start the iterations */
 306         iteration = 1;
 307         sync_global_to_guest(vm, iteration);
 308         host_quit = false;
 309         host_dirty_count = 0;
 310         host_clear_count = 0;
 311         host_track_next_count = 0;
 312
 313         pthread_create(&vcpu_thread, NULL, vcpu_worker, vm);
 314
 315         while (iteration < iterations) {
 316                 /* Give the vcpu thread some time to dirty some pages */
 317                 usleep(interval * 1000);
 318                 kvm_vm_get_dirty_log(vm, TEST_MEM_SLOT_INDEX, bmap);
 319                 vm_dirty_log_verify(bmap);
 320                 iteration++;
 321                 sync_global_to_guest(vm, iteration);
 322         }
 323
 324         /* Tell the vcpu thread to quit */
 325         host_quit = true;
 326         pthread_join(vcpu_thread, NULL);
 327
 328         DEBUG("Total bits checked: dirty (%"PRIu64"), clear (%"PRIu64"), "
 329               "track_next (%"PRIu64")\n", host_dirty_count, host_clear_count,
 330               host_track_next_count);
 331
 332         free(bmap);
 333         free(host_bmap_track);
 334         ucall_uninit(vm);
 335         kvm_vm_free(vm);
 336 }
 337
 338 static struct vm_guest_modes {
 339         enum vm_guest_mode mode;
 340         bool supported;
 341         bool enabled;
 342 } vm_guest_modes[NUM_VM_MODES] = {
 343 #if defined(__x86_64__)
 344         { VM_MODE_P52V48_4K,    1, 1, },
 345         { VM_MODE_P52V48_64K,   0, 0, },
 346         { VM_MODE_P40V48_4K,    0, 0, },
 347         { VM_MODE_P40V48_64K,   0, 0, },
 348 #elif defined(__aarch64__)
 349         { VM_MODE_P52V48_4K,    0, 0, },
 350         { VM_MODE_P52V48_64K,   0, 0, },
 351         { VM_MODE_P40V48_4K,    1, 1, },
 352         { VM_MODE_P40V48_64K,   1, 1, },
 353 #endif
 354 };
 355
 356 static void help(char *name)
 357 {
 358         int i;
 359
 360         puts("");
 361         printf("usage: %s [-h] [-i iterations] [-I interval] "
 362                "[-o offset] [-t] [-m mode]\n", name);
 363         puts("");
 364         printf(" -i: specify iteration counts (default: %"PRIu64")\n",
 365                TEST_HOST_LOOP_N);
 366         printf(" -I: specify interval in ms (default: %"PRIu64" ms)\n",
 367                TEST_HOST_LOOP_INTERVAL);
 368         printf(" -o: guest test memory offset (default: 0x%lx)\n",
 369                DEFAULT_GUEST_TEST_MEM);
 370         printf(" -t: map guest test memory at the top of the allowed "
 371                "physical address range\n");
 372         printf(" -m: specify the guest mode ID to test "
 373                "(default: test all supported modes)\n"
 374                "     This option may be used multiple times.\n"
 375                "     Guest mode IDs:\n");
 376         for (i = 0; i < NUM_VM_MODES; ++i) {
 377                 printf("         %d:    %s%s\n",
 378                        vm_guest_modes[i].mode,
 379                        vm_guest_mode_string(vm_guest_modes[i].mode),
 380                        vm_guest_modes[i].supported ? " (supported)" : "");
 381         }
 382         puts("");
 383         exit(0);
 384 }
 385
 386 int main(int argc, char *argv[])
 387 {
 388         unsigned long iterations = TEST_HOST_LOOP_N;
 389         unsigned long interval = TEST_HOST_LOOP_INTERVAL;
 390         bool mode_selected = false;
 391         bool top_offset = false;
 392         unsigned int mode;
 393         int opt, i;
 394
 395         while ((opt = getopt(argc, argv, "hi:I:o:tm:")) != -1) {
 396                 switch (opt) {
 397                 case 'i':
 398                         iterations = strtol(optarg, NULL, 10);
 399                         break;
 400                 case 'I':
 401                         interval = strtol(optarg, NULL, 10);
 402                         break;
 403                 case 'o':
 404                         guest_test_mem = strtoull(optarg, NULL, 0);
 405                         break;
 406                 case 't':
 407                         top_offset = true;
 408                         break;
 409                 case 'm':
 410                         if (!mode_selected) {
 411                                 for (i = 0; i < NUM_VM_MODES; ++i)
 412                                         vm_guest_modes[i].enabled = 0;
 413                                 mode_selected = true;
 414                         }
 415                         mode = strtoul(optarg, NULL, 10);
 416                         TEST_ASSERT(mode < NUM_VM_MODES,
 417                                     "Guest mode ID %d too big", mode);
 418                         vm_guest_modes[mode].enabled = 1;
 419                         break;
 420                 case 'h':
 421                 default:
 422                         help(argv[0]);
 423                         break;
 424                 }
 425         }
 426
 427         TEST_ASSERT(iterations > 2, "Iterations must be greater than two");
 428         TEST_ASSERT(interval > 0, "Interval must be greater than zero");
 429         TEST_ASSERT(!top_offset || guest_test_mem == DEFAULT_GUEST_TEST_MEM,
 430                     "Cannot use both -o [offset] and -t at the same time");
 431
 432         DEBUG("Test iterations: %"PRIu64", interval: %"PRIu64" (ms)\n",
 433               iterations, interval);
 434
 435         srandom(time(0));
 436
 437         for (i = 0; i < NUM_VM_MODES; ++i) {
 438                 if (!vm_guest_modes[i].enabled)
 439                         continue;
 440                 TEST_ASSERT(vm_guest_modes[i].supported,
 441                             "Guest mode ID %d (%s) not supported.",
 442                             vm_guest_modes[i].mode,
 443                             vm_guest_mode_string(vm_guest_modes[i].mode));
 444                 run_test(vm_guest_modes[i].mode, iterations, interval, top_offset);
 445         }
 446
 447         return 0;
 448 }