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(mode, nr_vcpus, 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 "]\n", 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#ifdef __s390x__ 200 /* Align to 1M (segment size) */ 201 args->gpa = align_down(args->gpa, 1 << 20); 202#endif 203 args->size = guest_num_pages * args->guest_page_size; 204 pr_info("guest physical test memory: [0x%lx, 0x%lx)\n", 205 args->gpa, args->gpa + args->size); 206 207 /* Add extra memory slots for testing */ 208 for (i = 0; i < slots; i++) { 209 uint64_t region_pages = guest_num_pages / slots; 210 vm_paddr_t region_start = args->gpa + region_pages * args->guest_page_size * i; 211 212 vm_userspace_mem_region_add(vm, backing_src, region_start, 213 MEMSTRESS_MEM_SLOT_INDEX + i, 214 region_pages, 0); 215 } 216 217 /* Do mapping for the demand paging memory slot */ 218 virt_map(vm, guest_test_virt_mem, args->gpa, guest_num_pages); 219 220 memstress_setup_vcpus(vm, nr_vcpus, vcpus, vcpu_memory_bytes, 221 partition_vcpu_memory_access); 222 223 if (args->nested) { 224 pr_info("Configuring vCPUs to run in L2 (nested).\n"); 225 memstress_setup_nested(vm, nr_vcpus, vcpus); 226 } 227 228 /* Export the shared variables to the guest. */ 229 sync_global_to_guest(vm, memstress_args); 230 231 return vm; 232} 233 234void memstress_destroy_vm(struct kvm_vm *vm) 235{ 236 kvm_vm_free(vm); 237} 238 239void memstress_set_write_percent(struct kvm_vm *vm, uint32_t write_percent) 240{ 241 memstress_args.write_percent = write_percent; 242 sync_global_to_guest(vm, memstress_args.write_percent); 243} 244 245void memstress_set_random_seed(struct kvm_vm *vm, uint32_t random_seed) 246{ 247 memstress_args.random_seed = random_seed; 248 sync_global_to_guest(vm, memstress_args.random_seed); 249} 250 251void memstress_set_random_access(struct kvm_vm *vm, bool random_access) 252{ 253 memstress_args.random_access = random_access; 254 sync_global_to_guest(vm, memstress_args.random_access); 255} 256 257uint64_t __weak memstress_nested_pages(int nr_vcpus) 258{ 259 return 0; 260} 261 262void __weak memstress_setup_nested(struct kvm_vm *vm, int nr_vcpus, struct kvm_vcpu **vcpus) 263{ 264 pr_info("%s() not support on this architecture, skipping.\n", __func__); 265 exit(KSFT_SKIP); 266} 267 268static void *vcpu_thread_main(void *data) 269{ 270 struct vcpu_thread *vcpu = data; 271 int vcpu_idx = vcpu->vcpu_idx; 272 273 if (memstress_args.pin_vcpus) 274 kvm_pin_this_task_to_pcpu(memstress_args.vcpu_to_pcpu[vcpu_idx]); 275 276 WRITE_ONCE(vcpu->running, true); 277 278 /* 279 * Wait for all vCPU threads to be up and running before calling the test- 280 * provided vCPU thread function. This prevents thread creation (which 281 * requires taking the mmap_sem in write mode) from interfering with the 282 * guest faulting in its memory. 283 */ 284 while (!READ_ONCE(all_vcpu_threads_running)) 285 ; 286 287 vcpu_thread_fn(&memstress_args.vcpu_args[vcpu_idx]); 288 289 return NULL; 290} 291 292void memstress_start_vcpu_threads(int nr_vcpus, 293 void (*vcpu_fn)(struct memstress_vcpu_args *)) 294{ 295 int i; 296 297 vcpu_thread_fn = vcpu_fn; 298 WRITE_ONCE(all_vcpu_threads_running, false); 299 WRITE_ONCE(memstress_args.stop_vcpus, false); 300 301 for (i = 0; i < nr_vcpus; i++) { 302 struct vcpu_thread *vcpu = &vcpu_threads[i]; 303 304 vcpu->vcpu_idx = i; 305 WRITE_ONCE(vcpu->running, false); 306 307 pthread_create(&vcpu->thread, NULL, vcpu_thread_main, vcpu); 308 } 309 310 for (i = 0; i < nr_vcpus; i++) { 311 while (!READ_ONCE(vcpu_threads[i].running)) 312 ; 313 } 314 315 WRITE_ONCE(all_vcpu_threads_running, true); 316} 317 318void memstress_join_vcpu_threads(int nr_vcpus) 319{ 320 int i; 321 322 WRITE_ONCE(memstress_args.stop_vcpus, true); 323 324 for (i = 0; i < nr_vcpus; i++) 325 pthread_join(vcpu_threads[i].thread, NULL); 326} 327 328static void toggle_dirty_logging(struct kvm_vm *vm, int slots, bool enable) 329{ 330 int i; 331 332 for (i = 0; i < slots; i++) { 333 int slot = MEMSTRESS_MEM_SLOT_INDEX + i; 334 int flags = enable ? KVM_MEM_LOG_DIRTY_PAGES : 0; 335 336 vm_mem_region_set_flags(vm, slot, flags); 337 } 338} 339 340void memstress_enable_dirty_logging(struct kvm_vm *vm, int slots) 341{ 342 toggle_dirty_logging(vm, slots, true); 343} 344 345void memstress_disable_dirty_logging(struct kvm_vm *vm, int slots) 346{ 347 toggle_dirty_logging(vm, slots, false); 348} 349 350void memstress_get_dirty_log(struct kvm_vm *vm, unsigned long *bitmaps[], int slots) 351{ 352 int i; 353 354 for (i = 0; i < slots; i++) { 355 int slot = MEMSTRESS_MEM_SLOT_INDEX + i; 356 357 kvm_vm_get_dirty_log(vm, slot, bitmaps[i]); 358 } 359} 360 361void memstress_clear_dirty_log(struct kvm_vm *vm, unsigned long *bitmaps[], 362 int slots, uint64_t pages_per_slot) 363{ 364 int i; 365 366 for (i = 0; i < slots; i++) { 367 int slot = MEMSTRESS_MEM_SLOT_INDEX + i; 368 369 kvm_vm_clear_dirty_log(vm, slot, bitmaps[i], 0, pages_per_slot); 370 } 371} 372 373unsigned long **memstress_alloc_bitmaps(int slots, uint64_t pages_per_slot) 374{ 375 unsigned long **bitmaps; 376 int i; 377 378 bitmaps = malloc(slots * sizeof(bitmaps[0])); 379 TEST_ASSERT(bitmaps, "Failed to allocate bitmaps array."); 380 381 for (i = 0; i < slots; i++) { 382 bitmaps[i] = bitmap_zalloc(pages_per_slot); 383 TEST_ASSERT(bitmaps[i], "Failed to allocate slot bitmap."); 384 } 385 386 return bitmaps; 387} 388 389void memstress_free_bitmaps(unsigned long *bitmaps[], int slots) 390{ 391 int i; 392 393 for (i = 0; i < slots; i++) 394 free(bitmaps[i]); 395 396 free(bitmaps); 397} 398