1// SPDX-License-Identifier: GPL-2.0 2/* 3 * Copyright (C) 2020, Google LLC. 4 */ 5#define _GNU_SOURCE 6 7#include <inttypes.h> 8#include <linux/bitmap.h> 9 10#include "kvm_util.h" 11#include "memstress.h" 12#include "processor.h" 13 14struct memstress_args memstress_args; 15 16/* 17 * Guest virtual memory offset of the testing memory slot. 18 * Must not conflict with identity mapped test code. 19 */ 20static uint64_t guest_test_virt_mem = DEFAULT_GUEST_TEST_MEM; 21 22struct vcpu_thread { 23 /* The index of the vCPU. */ 24 int vcpu_idx; 25 26 /* The pthread backing the vCPU. */ 27 pthread_t thread; 28 29 /* Set to true once the vCPU thread is up and running. */ 30 bool running; 31}; 32 33/* The vCPU threads involved in this test. */ 34static struct vcpu_thread vcpu_threads[KVM_MAX_VCPUS]; 35 36/* The function run by each vCPU thread, as provided by the test. */ 37static void (*vcpu_thread_fn)(struct memstress_vcpu_args *); 38 39/* Set to true once all vCPU threads are up and running. */ 40static bool all_vcpu_threads_running; 41 42static struct kvm_vcpu *vcpus[KVM_MAX_VCPUS]; 43 44/* 45 * Continuously write to the first 8 bytes of each page in the 46 * specified region. 47 */ 48void memstress_guest_code(uint32_t vcpu_idx) 49{ 50 struct memstress_args *args = &memstress_args; 51 struct memstress_vcpu_args *vcpu_args = &args->vcpu_args[vcpu_idx]; 52 struct guest_random_state rand_state; 53 uint64_t gva; 54 uint64_t pages; 55 uint64_t addr; 56 uint64_t page; 57 int i; 58 59 rand_state = new_guest_random_state(args->random_seed + vcpu_idx); 60 61 gva = vcpu_args->gva; 62 pages = vcpu_args->pages; 63 64 /* Make sure vCPU args data structure is not corrupt. */ 65 GUEST_ASSERT(vcpu_args->vcpu_idx == vcpu_idx); 66 67 while (true) { 68 for (i = 0; i < sizeof(memstress_args); i += args->guest_page_size) 69 (void) *((volatile char *)args + i); 70 71 for (i = 0; i < pages; i++) { 72 if (args->random_access) 73 page = guest_random_u32(&rand_state) % pages; 74 else 75 page = i; 76 77 addr = gva + (page * args->guest_page_size); 78 79 if (guest_random_u32(&rand_state) % 100 < args->write_percent) 80 *(uint64_t *)addr = 0x0123456789ABCDEF; 81 else 82 READ_ONCE(*(uint64_t *)addr); 83 } 84 85 GUEST_SYNC(1); 86 } 87} 88 89void memstress_setup_vcpus(struct kvm_vm *vm, int nr_vcpus, 90 struct kvm_vcpu *vcpus[], 91 uint64_t vcpu_memory_bytes, 92 bool partition_vcpu_memory_access) 93{ 94 struct memstress_args *args = &memstress_args; 95 struct memstress_vcpu_args *vcpu_args; 96 int i; 97 98 for (i = 0; i < nr_vcpus; i++) { 99 vcpu_args = &args->vcpu_args[i]; 100 101 vcpu_args->vcpu = vcpus[i]; 102 vcpu_args->vcpu_idx = i; 103 104 if (partition_vcpu_memory_access) { 105 vcpu_args->gva = guest_test_virt_mem + 106 (i * vcpu_memory_bytes); 107 vcpu_args->pages = vcpu_memory_bytes / 108 args->guest_page_size; 109 vcpu_args->gpa = args->gpa + (i * vcpu_memory_bytes); 110 } else { 111 vcpu_args->gva = guest_test_virt_mem; 112 vcpu_args->pages = (nr_vcpus * vcpu_memory_bytes) / 113 args->guest_page_size; 114 vcpu_args->gpa = args->gpa; 115 } 116 117 vcpu_args_set(vcpus[i], 1, i); 118 119 pr_debug("Added VCPU %d with test mem gpa [%lx, %lx)\n", 120 i, vcpu_args->gpa, vcpu_args->gpa + 121 (vcpu_args->pages * args->guest_page_size)); 122 } 123} 124 125struct kvm_vm *memstress_create_vm(enum vm_guest_mode mode, int nr_vcpus, 126 uint64_t vcpu_memory_bytes, int slots, 127 enum vm_mem_backing_src_type backing_src, 128 bool partition_vcpu_memory_access) 129{ 130 struct memstress_args *args = &memstress_args; 131 struct kvm_vm *vm; 132 uint64_t guest_num_pages, slot0_pages = 0; 133 uint64_t backing_src_pagesz = get_backing_src_pagesz(backing_src); 134 uint64_t region_end_gfn; 135 int i; 136 137 pr_info("Testing guest mode: %s\n", vm_guest_mode_string(mode)); 138 139 /* By default vCPUs will write to memory. */ 140 args->write_percent = 100; 141 142 /* 143 * Snapshot the non-huge page size. This is used by the guest code to 144 * access/dirty pages at the logging granularity. 145 */ 146 args->guest_page_size = vm_guest_mode_params[mode].page_size; 147 148 guest_num_pages = vm_adjust_num_guest_pages(mode, 149 (nr_vcpus * vcpu_memory_bytes) / args->guest_page_size); 150 151 TEST_ASSERT(vcpu_memory_bytes % getpagesize() == 0, 152 "Guest memory size is not host page size aligned."); 153 TEST_ASSERT(vcpu_memory_bytes % args->guest_page_size == 0, 154 "Guest memory size is not guest page size aligned."); 155 TEST_ASSERT(guest_num_pages % slots == 0, 156 "Guest memory cannot be evenly divided into %d slots.", 157 slots); 158 159 /* 160 * If using nested, allocate extra pages for the nested page tables and 161 * in-memory data structures. 162 */ 163 if (args->nested) 164 slot0_pages += memstress_nested_pages(nr_vcpus); 165 166 /* 167 * Pass guest_num_pages to populate the page tables for test memory. 168 * The memory is also added to memslot 0, but that's a benign side 169 * effect as KVM allows aliasing HVAs in meslots. 170 */ 171 vm = __vm_create_with_vcpus(VM_SHAPE(mode), nr_vcpus, 172 slot0_pages + guest_num_pages, 173 memstress_guest_code, vcpus); 174 175 args->vm = vm; 176 177 /* Put the test region at the top guest physical memory. */ 178 region_end_gfn = vm->max_gfn + 1; 179 180#ifdef __x86_64__ 181 /* 182 * When running vCPUs in L2, restrict the test region to 48 bits to 183 * avoid needing 5-level page tables to identity map L2. 184 */ 185 if (args->nested) 186 region_end_gfn = min(region_end_gfn, (1UL << 48) / args->guest_page_size); 187#endif 188 /* 189 * If there should be more memory in the guest test region than there 190 * can be pages in the guest, it will definitely cause problems. 191 */ 192 TEST_ASSERT(guest_num_pages < region_end_gfn, 193 "Requested more guest memory than address space allows.\n" 194 " guest pages: %" PRIx64 " max gfn: %" PRIx64 195 " nr_vcpus: %d wss: %" PRIx64 "]", 196 guest_num_pages, region_end_gfn - 1, nr_vcpus, vcpu_memory_bytes); 197 198 args->gpa = (region_end_gfn - guest_num_pages - 1) * args->guest_page_size; 199 args->gpa = align_down(args->gpa, backing_src_pagesz); 200#ifdef __s390x__ 201 /* Align to 1M (segment size) */ 202 args->gpa = align_down(args->gpa, 1 << 20); 203#endif 204 args->size = guest_num_pages * args->guest_page_size; 205 pr_info("guest physical test memory: [0x%lx, 0x%lx)\n", 206 args->gpa, args->gpa + args->size); 207 208 /* Add extra memory slots for testing */ 209 for (i = 0; i < slots; i++) { 210 uint64_t region_pages = guest_num_pages / slots; 211 vm_paddr_t region_start = args->gpa + region_pages * args->guest_page_size * i; 212 213 vm_userspace_mem_region_add(vm, backing_src, region_start, 214 MEMSTRESS_MEM_SLOT_INDEX + i, 215 region_pages, 0); 216 } 217 218 /* Do mapping for the demand paging memory slot */ 219 virt_map(vm, guest_test_virt_mem, args->gpa, guest_num_pages); 220 221 memstress_setup_vcpus(vm, nr_vcpus, vcpus, vcpu_memory_bytes, 222 partition_vcpu_memory_access); 223 224 if (args->nested) { 225 pr_info("Configuring vCPUs to run in L2 (nested).\n"); 226 memstress_setup_nested(vm, nr_vcpus, vcpus); 227 } 228 229 /* Export the shared variables to the guest. */ 230 sync_global_to_guest(vm, memstress_args); 231 232 return vm; 233} 234 235void memstress_destroy_vm(struct kvm_vm *vm) 236{ 237 kvm_vm_free(vm); 238} 239 240void memstress_set_write_percent(struct kvm_vm *vm, uint32_t write_percent) 241{ 242 memstress_args.write_percent = write_percent; 243 sync_global_to_guest(vm, memstress_args.write_percent); 244} 245 246void memstress_set_random_seed(struct kvm_vm *vm, uint32_t random_seed) 247{ 248 memstress_args.random_seed = random_seed; 249 sync_global_to_guest(vm, memstress_args.random_seed); 250} 251 252void memstress_set_random_access(struct kvm_vm *vm, bool random_access) 253{ 254 memstress_args.random_access = random_access; 255 sync_global_to_guest(vm, memstress_args.random_access); 256} 257 258uint64_t __weak memstress_nested_pages(int nr_vcpus) 259{ 260 return 0; 261} 262 263void __weak memstress_setup_nested(struct kvm_vm *vm, int nr_vcpus, struct kvm_vcpu **vcpus) 264{ 265 pr_info("%s() not support on this architecture, skipping.\n", __func__); 266 exit(KSFT_SKIP); 267} 268 269static void *vcpu_thread_main(void *data) 270{ 271 struct vcpu_thread *vcpu = data; 272 int vcpu_idx = vcpu->vcpu_idx; 273 274 if (memstress_args.pin_vcpus) 275 kvm_pin_this_task_to_pcpu(memstress_args.vcpu_to_pcpu[vcpu_idx]); 276 277 WRITE_ONCE(vcpu->running, true); 278 279 /* 280 * Wait for all vCPU threads to be up and running before calling the test- 281 * provided vCPU thread function. This prevents thread creation (which 282 * requires taking the mmap_sem in write mode) from interfering with the 283 * guest faulting in its memory. 284 */ 285 while (!READ_ONCE(all_vcpu_threads_running)) 286 ; 287 288 vcpu_thread_fn(&memstress_args.vcpu_args[vcpu_idx]); 289 290 return NULL; 291} 292 293void memstress_start_vcpu_threads(int nr_vcpus, 294 void (*vcpu_fn)(struct memstress_vcpu_args *)) 295{ 296 int i; 297 298 vcpu_thread_fn = vcpu_fn; 299 WRITE_ONCE(all_vcpu_threads_running, false); 300 WRITE_ONCE(memstress_args.stop_vcpus, false); 301 302 for (i = 0; i < nr_vcpus; i++) { 303 struct vcpu_thread *vcpu = &vcpu_threads[i]; 304 305 vcpu->vcpu_idx = i; 306 WRITE_ONCE(vcpu->running, false); 307 308 pthread_create(&vcpu->thread, NULL, vcpu_thread_main, vcpu); 309 } 310 311 for (i = 0; i < nr_vcpus; i++) { 312 while (!READ_ONCE(vcpu_threads[i].running)) 313 ; 314 } 315 316 WRITE_ONCE(all_vcpu_threads_running, true); 317} 318 319void memstress_join_vcpu_threads(int nr_vcpus) 320{ 321 int i; 322 323 WRITE_ONCE(memstress_args.stop_vcpus, true); 324 325 for (i = 0; i < nr_vcpus; i++) 326 pthread_join(vcpu_threads[i].thread, NULL); 327} 328 329static void toggle_dirty_logging(struct kvm_vm *vm, int slots, bool enable) 330{ 331 int i; 332 333 for (i = 0; i < slots; i++) { 334 int slot = MEMSTRESS_MEM_SLOT_INDEX + i; 335 int flags = enable ? KVM_MEM_LOG_DIRTY_PAGES : 0; 336 337 vm_mem_region_set_flags(vm, slot, flags); 338 } 339} 340 341void memstress_enable_dirty_logging(struct kvm_vm *vm, int slots) 342{ 343 toggle_dirty_logging(vm, slots, true); 344} 345 346void memstress_disable_dirty_logging(struct kvm_vm *vm, int slots) 347{ 348 toggle_dirty_logging(vm, slots, false); 349} 350 351void memstress_get_dirty_log(struct kvm_vm *vm, unsigned long *bitmaps[], int slots) 352{ 353 int i; 354 355 for (i = 0; i < slots; i++) { 356 int slot = MEMSTRESS_MEM_SLOT_INDEX + i; 357 358 kvm_vm_get_dirty_log(vm, slot, bitmaps[i]); 359 } 360} 361 362void memstress_clear_dirty_log(struct kvm_vm *vm, unsigned long *bitmaps[], 363 int slots, uint64_t pages_per_slot) 364{ 365 int i; 366 367 for (i = 0; i < slots; i++) { 368 int slot = MEMSTRESS_MEM_SLOT_INDEX + i; 369 370 kvm_vm_clear_dirty_log(vm, slot, bitmaps[i], 0, pages_per_slot); 371 } 372} 373 374unsigned long **memstress_alloc_bitmaps(int slots, uint64_t pages_per_slot) 375{ 376 unsigned long **bitmaps; 377 int i; 378 379 bitmaps = malloc(slots * sizeof(bitmaps[0])); 380 TEST_ASSERT(bitmaps, "Failed to allocate bitmaps array."); 381 382 for (i = 0; i < slots; i++) { 383 bitmaps[i] = bitmap_zalloc(pages_per_slot); 384 TEST_ASSERT(bitmaps[i], "Failed to allocate slot bitmap."); 385 } 386 387 return bitmaps; 388} 389 390void memstress_free_bitmaps(unsigned long *bitmaps[], int slots) 391{ 392 int i; 393 394 for (i = 0; i < slots; i++) 395 free(bitmaps[i]); 396 397 free(bitmaps); 398} 399