1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * KVM dirty page logging performance test 4 * 5 * Based on dirty_log_test.c 6 * 7 * Copyright (C) 2018, Red Hat, Inc. 8 * Copyright (C) 2020, Google, Inc. 9 */ 10 11 #include <stdio.h> 12 #include <stdlib.h> 13 #include <time.h> 14 #include <pthread.h> 15 #include <linux/bitmap.h> 16 17 #include "kvm_util.h" 18 #include "test_util.h" 19 #include "perf_test_util.h" 20 #include "guest_modes.h" 21 22 #ifdef __aarch64__ 23 #include "aarch64/vgic.h" 24 25 #define GICD_BASE_GPA 0x8000000ULL 26 #define GICR_BASE_GPA 0x80A0000ULL 27 28 static int gic_fd; 29 30 static void arch_setup_vm(struct kvm_vm *vm, unsigned int nr_vcpus) 31 { 32 /* 33 * The test can still run even if hardware does not support GICv3, as it 34 * is only an optimization to reduce guest exits. 35 */ 36 gic_fd = vgic_v3_setup(vm, nr_vcpus, 64, GICD_BASE_GPA, GICR_BASE_GPA); 37 } 38 39 static void arch_cleanup_vm(struct kvm_vm *vm) 40 { 41 if (gic_fd > 0) 42 close(gic_fd); 43 } 44 45 #else /* __aarch64__ */ 46 47 static void arch_setup_vm(struct kvm_vm *vm, unsigned int nr_vcpus) 48 { 49 } 50 51 static void arch_cleanup_vm(struct kvm_vm *vm) 52 { 53 } 54 55 #endif 56 57 /* How many host loops to run by default (one KVM_GET_DIRTY_LOG for each loop)*/ 58 #define TEST_HOST_LOOP_N 2UL 59 60 static int nr_vcpus = 1; 61 static uint64_t guest_percpu_mem_size = DEFAULT_PER_VCPU_MEM_SIZE; 62 static bool run_vcpus_while_disabling_dirty_logging; 63 64 /* Host variables */ 65 static u64 dirty_log_manual_caps; 66 static bool host_quit; 67 static int iteration; 68 static int vcpu_last_completed_iteration[KVM_MAX_VCPUS]; 69 70 static void vcpu_worker(struct perf_test_vcpu_args *vcpu_args) 71 { 72 struct kvm_vcpu *vcpu = vcpu_args->vcpu; 73 int vcpu_idx = vcpu_args->vcpu_idx; 74 uint64_t pages_count = 0; 75 struct kvm_run *run; 76 struct timespec start; 77 struct timespec ts_diff; 78 struct timespec total = (struct timespec){0}; 79 struct timespec avg; 80 int ret; 81 82 run = vcpu->run; 83 84 while (!READ_ONCE(host_quit)) { 85 int current_iteration = READ_ONCE(iteration); 86 87 clock_gettime(CLOCK_MONOTONIC, &start); 88 ret = _vcpu_run(vcpu); 89 ts_diff = timespec_elapsed(start); 90 91 TEST_ASSERT(ret == 0, "vcpu_run failed: %d\n", ret); 92 TEST_ASSERT(get_ucall(vcpu, NULL) == UCALL_SYNC, 93 "Invalid guest sync status: exit_reason=%s\n", 94 exit_reason_str(run->exit_reason)); 95 96 pr_debug("Got sync event from vCPU %d\n", vcpu_idx); 97 vcpu_last_completed_iteration[vcpu_idx] = current_iteration; 98 pr_debug("vCPU %d updated last completed iteration to %d\n", 99 vcpu_idx, vcpu_last_completed_iteration[vcpu_idx]); 100 101 if (current_iteration) { 102 pages_count += vcpu_args->pages; 103 total = timespec_add(total, ts_diff); 104 pr_debug("vCPU %d iteration %d dirty memory time: %ld.%.9lds\n", 105 vcpu_idx, current_iteration, ts_diff.tv_sec, 106 ts_diff.tv_nsec); 107 } else { 108 pr_debug("vCPU %d iteration %d populate memory time: %ld.%.9lds\n", 109 vcpu_idx, current_iteration, ts_diff.tv_sec, 110 ts_diff.tv_nsec); 111 } 112 113 /* 114 * Keep running the guest while dirty logging is being disabled 115 * (iteration is negative) so that vCPUs are accessing memory 116 * for the entire duration of zapping collapsible SPTEs. 117 */ 118 while (current_iteration == READ_ONCE(iteration) && 119 READ_ONCE(iteration) >= 0 && !READ_ONCE(host_quit)) {} 120 } 121 122 avg = timespec_div(total, vcpu_last_completed_iteration[vcpu_idx]); 123 pr_debug("\nvCPU %d dirtied 0x%lx pages over %d iterations in %ld.%.9lds. (Avg %ld.%.9lds/iteration)\n", 124 vcpu_idx, pages_count, vcpu_last_completed_iteration[vcpu_idx], 125 total.tv_sec, total.tv_nsec, avg.tv_sec, avg.tv_nsec); 126 } 127 128 struct test_params { 129 unsigned long iterations; 130 uint64_t phys_offset; 131 int wr_fract; 132 bool partition_vcpu_memory_access; 133 enum vm_mem_backing_src_type backing_src; 134 int slots; 135 }; 136 137 static void toggle_dirty_logging(struct kvm_vm *vm, int slots, bool enable) 138 { 139 int i; 140 141 for (i = 0; i < slots; i++) { 142 int slot = PERF_TEST_MEM_SLOT_INDEX + i; 143 int flags = enable ? KVM_MEM_LOG_DIRTY_PAGES : 0; 144 145 vm_mem_region_set_flags(vm, slot, flags); 146 } 147 } 148 149 static inline void enable_dirty_logging(struct kvm_vm *vm, int slots) 150 { 151 toggle_dirty_logging(vm, slots, true); 152 } 153 154 static inline void disable_dirty_logging(struct kvm_vm *vm, int slots) 155 { 156 toggle_dirty_logging(vm, slots, false); 157 } 158 159 static void get_dirty_log(struct kvm_vm *vm, unsigned long *bitmaps[], int slots) 160 { 161 int i; 162 163 for (i = 0; i < slots; i++) { 164 int slot = PERF_TEST_MEM_SLOT_INDEX + i; 165 166 kvm_vm_get_dirty_log(vm, slot, bitmaps[i]); 167 } 168 } 169 170 static void clear_dirty_log(struct kvm_vm *vm, unsigned long *bitmaps[], 171 int slots, uint64_t pages_per_slot) 172 { 173 int i; 174 175 for (i = 0; i < slots; i++) { 176 int slot = PERF_TEST_MEM_SLOT_INDEX + i; 177 178 kvm_vm_clear_dirty_log(vm, slot, bitmaps[i], 0, pages_per_slot); 179 } 180 } 181 182 static unsigned long **alloc_bitmaps(int slots, uint64_t pages_per_slot) 183 { 184 unsigned long **bitmaps; 185 int i; 186 187 bitmaps = malloc(slots * sizeof(bitmaps[0])); 188 TEST_ASSERT(bitmaps, "Failed to allocate bitmaps array."); 189 190 for (i = 0; i < slots; i++) { 191 bitmaps[i] = bitmap_zalloc(pages_per_slot); 192 TEST_ASSERT(bitmaps[i], "Failed to allocate slot bitmap."); 193 } 194 195 return bitmaps; 196 } 197 198 static void free_bitmaps(unsigned long *bitmaps[], int slots) 199 { 200 int i; 201 202 for (i = 0; i < slots; i++) 203 free(bitmaps[i]); 204 205 free(bitmaps); 206 } 207 208 static void run_test(enum vm_guest_mode mode, void *arg) 209 { 210 struct test_params *p = arg; 211 struct kvm_vm *vm; 212 unsigned long **bitmaps; 213 uint64_t guest_num_pages; 214 uint64_t host_num_pages; 215 uint64_t pages_per_slot; 216 struct timespec start; 217 struct timespec ts_diff; 218 struct timespec get_dirty_log_total = (struct timespec){0}; 219 struct timespec vcpu_dirty_total = (struct timespec){0}; 220 struct timespec avg; 221 struct timespec clear_dirty_log_total = (struct timespec){0}; 222 int i; 223 224 vm = perf_test_create_vm(mode, nr_vcpus, guest_percpu_mem_size, 225 p->slots, p->backing_src, 226 p->partition_vcpu_memory_access); 227 228 perf_test_set_wr_fract(vm, p->wr_fract); 229 230 guest_num_pages = (nr_vcpus * guest_percpu_mem_size) >> vm->page_shift; 231 guest_num_pages = vm_adjust_num_guest_pages(mode, guest_num_pages); 232 host_num_pages = vm_num_host_pages(mode, guest_num_pages); 233 pages_per_slot = host_num_pages / p->slots; 234 235 bitmaps = alloc_bitmaps(p->slots, pages_per_slot); 236 237 if (dirty_log_manual_caps) 238 vm_enable_cap(vm, KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2, 239 dirty_log_manual_caps); 240 241 arch_setup_vm(vm, nr_vcpus); 242 243 /* Start the iterations */ 244 iteration = 0; 245 host_quit = false; 246 247 clock_gettime(CLOCK_MONOTONIC, &start); 248 for (i = 0; i < nr_vcpus; i++) 249 vcpu_last_completed_iteration[i] = -1; 250 251 perf_test_start_vcpu_threads(nr_vcpus, vcpu_worker); 252 253 /* Allow the vCPUs to populate memory */ 254 pr_debug("Starting iteration %d - Populating\n", iteration); 255 for (i = 0; i < nr_vcpus; i++) { 256 while (READ_ONCE(vcpu_last_completed_iteration[i]) != 257 iteration) 258 ; 259 } 260 261 ts_diff = timespec_elapsed(start); 262 pr_info("Populate memory time: %ld.%.9lds\n", 263 ts_diff.tv_sec, ts_diff.tv_nsec); 264 265 /* Enable dirty logging */ 266 clock_gettime(CLOCK_MONOTONIC, &start); 267 enable_dirty_logging(vm, p->slots); 268 ts_diff = timespec_elapsed(start); 269 pr_info("Enabling dirty logging time: %ld.%.9lds\n\n", 270 ts_diff.tv_sec, ts_diff.tv_nsec); 271 272 while (iteration < p->iterations) { 273 /* 274 * Incrementing the iteration number will start the vCPUs 275 * dirtying memory again. 276 */ 277 clock_gettime(CLOCK_MONOTONIC, &start); 278 iteration++; 279 280 pr_debug("Starting iteration %d\n", iteration); 281 for (i = 0; i < nr_vcpus; i++) { 282 while (READ_ONCE(vcpu_last_completed_iteration[i]) 283 != iteration) 284 ; 285 } 286 287 ts_diff = timespec_elapsed(start); 288 vcpu_dirty_total = timespec_add(vcpu_dirty_total, ts_diff); 289 pr_info("Iteration %d dirty memory time: %ld.%.9lds\n", 290 iteration, ts_diff.tv_sec, ts_diff.tv_nsec); 291 292 clock_gettime(CLOCK_MONOTONIC, &start); 293 get_dirty_log(vm, bitmaps, p->slots); 294 ts_diff = timespec_elapsed(start); 295 get_dirty_log_total = timespec_add(get_dirty_log_total, 296 ts_diff); 297 pr_info("Iteration %d get dirty log time: %ld.%.9lds\n", 298 iteration, ts_diff.tv_sec, ts_diff.tv_nsec); 299 300 if (dirty_log_manual_caps) { 301 clock_gettime(CLOCK_MONOTONIC, &start); 302 clear_dirty_log(vm, bitmaps, p->slots, pages_per_slot); 303 ts_diff = timespec_elapsed(start); 304 clear_dirty_log_total = timespec_add(clear_dirty_log_total, 305 ts_diff); 306 pr_info("Iteration %d clear dirty log time: %ld.%.9lds\n", 307 iteration, ts_diff.tv_sec, ts_diff.tv_nsec); 308 } 309 } 310 311 /* 312 * Run vCPUs while dirty logging is being disabled to stress disabling 313 * in terms of both performance and correctness. Opt-in via command 314 * line as this significantly increases time to disable dirty logging. 315 */ 316 if (run_vcpus_while_disabling_dirty_logging) 317 WRITE_ONCE(iteration, -1); 318 319 /* Disable dirty logging */ 320 clock_gettime(CLOCK_MONOTONIC, &start); 321 disable_dirty_logging(vm, p->slots); 322 ts_diff = timespec_elapsed(start); 323 pr_info("Disabling dirty logging time: %ld.%.9lds\n", 324 ts_diff.tv_sec, ts_diff.tv_nsec); 325 326 /* 327 * Tell the vCPU threads to quit. No need to manually check that vCPUs 328 * have stopped running after disabling dirty logging, the join will 329 * wait for them to exit. 330 */ 331 host_quit = true; 332 perf_test_join_vcpu_threads(nr_vcpus); 333 334 avg = timespec_div(get_dirty_log_total, p->iterations); 335 pr_info("Get dirty log over %lu iterations took %ld.%.9lds. (Avg %ld.%.9lds/iteration)\n", 336 p->iterations, get_dirty_log_total.tv_sec, 337 get_dirty_log_total.tv_nsec, avg.tv_sec, avg.tv_nsec); 338 339 if (dirty_log_manual_caps) { 340 avg = timespec_div(clear_dirty_log_total, p->iterations); 341 pr_info("Clear dirty log over %lu iterations took %ld.%.9lds. (Avg %ld.%.9lds/iteration)\n", 342 p->iterations, clear_dirty_log_total.tv_sec, 343 clear_dirty_log_total.tv_nsec, avg.tv_sec, avg.tv_nsec); 344 } 345 346 free_bitmaps(bitmaps, p->slots); 347 arch_cleanup_vm(vm); 348 perf_test_destroy_vm(vm); 349 } 350 351 static void help(char *name) 352 { 353 puts(""); 354 printf("usage: %s [-h] [-i iterations] [-p offset] [-g] " 355 "[-m mode] [-n] [-b vcpu bytes] [-v vcpus] [-o] [-s mem type]" 356 "[-x memslots]\n", name); 357 puts(""); 358 printf(" -i: specify iteration counts (default: %"PRIu64")\n", 359 TEST_HOST_LOOP_N); 360 printf(" -g: Do not enable KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2. This\n" 361 " makes KVM_GET_DIRTY_LOG clear the dirty log (i.e.\n" 362 " KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE is not enabled)\n" 363 " and writes will be tracked as soon as dirty logging is\n" 364 " enabled on the memslot (i.e. KVM_DIRTY_LOG_INITIALLY_SET\n" 365 " is not enabled).\n"); 366 printf(" -p: specify guest physical test memory offset\n" 367 " Warning: a low offset can conflict with the loaded test code.\n"); 368 guest_modes_help(); 369 printf(" -n: Run the vCPUs in nested mode (L2)\n"); 370 printf(" -e: Run vCPUs while dirty logging is being disabled. This\n" 371 " can significantly increase runtime, especially if there\n" 372 " isn't a dedicated pCPU for the main thread.\n"); 373 printf(" -b: specify the size of the memory region which should be\n" 374 " dirtied by each vCPU. e.g. 10M or 3G.\n" 375 " (default: 1G)\n"); 376 printf(" -f: specify the fraction of pages which should be written to\n" 377 " as opposed to simply read, in the form\n" 378 " 1/<fraction of pages to write>.\n" 379 " (default: 1 i.e. all pages are written to.)\n"); 380 printf(" -v: specify the number of vCPUs to run.\n"); 381 printf(" -o: Overlap guest memory accesses instead of partitioning\n" 382 " them into a separate region of memory for each vCPU.\n"); 383 backing_src_help("-s"); 384 printf(" -x: Split the memory region into this number of memslots.\n" 385 " (default: 1)\n"); 386 puts(""); 387 exit(0); 388 } 389 390 int main(int argc, char *argv[]) 391 { 392 int max_vcpus = kvm_check_cap(KVM_CAP_MAX_VCPUS); 393 struct test_params p = { 394 .iterations = TEST_HOST_LOOP_N, 395 .wr_fract = 1, 396 .partition_vcpu_memory_access = true, 397 .backing_src = DEFAULT_VM_MEM_SRC, 398 .slots = 1, 399 }; 400 int opt; 401 402 dirty_log_manual_caps = 403 kvm_check_cap(KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2); 404 dirty_log_manual_caps &= (KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE | 405 KVM_DIRTY_LOG_INITIALLY_SET); 406 407 guest_modes_append_default(); 408 409 while ((opt = getopt(argc, argv, "b:ef:ghi:m:nop:s:v:x:")) != -1) { 410 switch (opt) { 411 case 'b': 412 guest_percpu_mem_size = parse_size(optarg); 413 break; 414 case 'e': 415 /* 'e' is for evil. */ 416 run_vcpus_while_disabling_dirty_logging = true; 417 break; 418 case 'f': 419 p.wr_fract = atoi_paranoid(optarg); 420 TEST_ASSERT(p.wr_fract >= 1, 421 "Write fraction cannot be less than one"); 422 break; 423 case 'g': 424 dirty_log_manual_caps = 0; 425 break; 426 case 'h': 427 help(argv[0]); 428 break; 429 case 'i': 430 p.iterations = atoi_paranoid(optarg); 431 break; 432 case 'm': 433 guest_modes_cmdline(optarg); 434 break; 435 case 'n': 436 perf_test_args.nested = true; 437 break; 438 case 'o': 439 p.partition_vcpu_memory_access = false; 440 break; 441 case 'p': 442 p.phys_offset = strtoull(optarg, NULL, 0); 443 break; 444 case 's': 445 p.backing_src = parse_backing_src_type(optarg); 446 break; 447 case 'v': 448 nr_vcpus = atoi_paranoid(optarg); 449 TEST_ASSERT(nr_vcpus > 0 && nr_vcpus <= max_vcpus, 450 "Invalid number of vcpus, must be between 1 and %d", max_vcpus); 451 break; 452 case 'x': 453 p.slots = atoi_paranoid(optarg); 454 break; 455 default: 456 help(argv[0]); 457 break; 458 } 459 } 460 461 TEST_ASSERT(p.iterations >= 2, "The test should have at least two iterations"); 462 463 pr_info("Test iterations: %"PRIu64"\n", p.iterations); 464 465 for_each_guest_mode(run_test, &p); 466 467 return 0; 468 } 469