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