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 9 #include "kvm_util.h" 10 #include "memstress.h" 11 #include "processor.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 */ memstress_guest_code(uint32_t vcpu_idx)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(args->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 < pages; i++) { 68 if (args->random_access) 69 page = guest_random_u32(&rand_state) % pages; 70 else 71 page = i; 72 73 addr = gva + (page * args->guest_page_size); 74 75 if (guest_random_u32(&rand_state) % 100 < args->write_percent) 76 *(uint64_t *)addr = 0x0123456789ABCDEF; 77 else 78 READ_ONCE(*(uint64_t *)addr); 79 } 80 81 GUEST_SYNC(1); 82 } 83 } 84 memstress_setup_vcpus(struct kvm_vm * vm,int nr_vcpus,struct kvm_vcpu * vcpus[],uint64_t vcpu_memory_bytes,bool partition_vcpu_memory_access)85 void memstress_setup_vcpus(struct kvm_vm *vm, int nr_vcpus, 86 struct kvm_vcpu *vcpus[], 87 uint64_t vcpu_memory_bytes, 88 bool partition_vcpu_memory_access) 89 { 90 struct memstress_args *args = &memstress_args; 91 struct memstress_vcpu_args *vcpu_args; 92 int i; 93 94 for (i = 0; i < nr_vcpus; i++) { 95 vcpu_args = &args->vcpu_args[i]; 96 97 vcpu_args->vcpu = vcpus[i]; 98 vcpu_args->vcpu_idx = i; 99 100 if (partition_vcpu_memory_access) { 101 vcpu_args->gva = guest_test_virt_mem + 102 (i * vcpu_memory_bytes); 103 vcpu_args->pages = vcpu_memory_bytes / 104 args->guest_page_size; 105 vcpu_args->gpa = args->gpa + (i * vcpu_memory_bytes); 106 } else { 107 vcpu_args->gva = guest_test_virt_mem; 108 vcpu_args->pages = (nr_vcpus * vcpu_memory_bytes) / 109 args->guest_page_size; 110 vcpu_args->gpa = args->gpa; 111 } 112 113 vcpu_args_set(vcpus[i], 1, i); 114 115 pr_debug("Added VCPU %d with test mem gpa [%lx, %lx)\n", 116 i, vcpu_args->gpa, vcpu_args->gpa + 117 (vcpu_args->pages * args->guest_page_size)); 118 } 119 } 120 memstress_create_vm(enum vm_guest_mode mode,int nr_vcpus,uint64_t vcpu_memory_bytes,int slots,enum vm_mem_backing_src_type backing_src,bool partition_vcpu_memory_access)121 struct kvm_vm *memstress_create_vm(enum vm_guest_mode mode, int nr_vcpus, 122 uint64_t vcpu_memory_bytes, int slots, 123 enum vm_mem_backing_src_type backing_src, 124 bool partition_vcpu_memory_access) 125 { 126 struct memstress_args *args = &memstress_args; 127 struct kvm_vm *vm; 128 uint64_t guest_num_pages, slot0_pages = 0; 129 uint64_t backing_src_pagesz = get_backing_src_pagesz(backing_src); 130 uint64_t region_end_gfn; 131 int i; 132 133 pr_info("Testing guest mode: %s\n", vm_guest_mode_string(mode)); 134 135 /* By default vCPUs will write to memory. */ 136 args->write_percent = 100; 137 138 /* 139 * Snapshot the non-huge page size. This is used by the guest code to 140 * access/dirty pages at the logging granularity. 141 */ 142 args->guest_page_size = vm_guest_mode_params[mode].page_size; 143 144 guest_num_pages = vm_adjust_num_guest_pages(mode, 145 (nr_vcpus * vcpu_memory_bytes) / args->guest_page_size); 146 147 TEST_ASSERT(vcpu_memory_bytes % getpagesize() == 0, 148 "Guest memory size is not host page size aligned."); 149 TEST_ASSERT(vcpu_memory_bytes % args->guest_page_size == 0, 150 "Guest memory size is not guest page size aligned."); 151 TEST_ASSERT(guest_num_pages % slots == 0, 152 "Guest memory cannot be evenly divided into %d slots.", 153 slots); 154 155 /* 156 * If using nested, allocate extra pages for the nested page tables and 157 * in-memory data structures. 158 */ 159 if (args->nested) 160 slot0_pages += memstress_nested_pages(nr_vcpus); 161 162 /* 163 * Pass guest_num_pages to populate the page tables for test memory. 164 * The memory is also added to memslot 0, but that's a benign side 165 * effect as KVM allows aliasing HVAs in meslots. 166 */ 167 vm = __vm_create_with_vcpus(mode, nr_vcpus, slot0_pages + guest_num_pages, 168 memstress_guest_code, vcpus); 169 170 args->vm = vm; 171 172 /* Put the test region at the top guest physical memory. */ 173 region_end_gfn = vm->max_gfn + 1; 174 175 #ifdef __x86_64__ 176 /* 177 * When running vCPUs in L2, restrict the test region to 48 bits to 178 * avoid needing 5-level page tables to identity map L2. 179 */ 180 if (args->nested) 181 region_end_gfn = min(region_end_gfn, (1UL << 48) / args->guest_page_size); 182 #endif 183 /* 184 * If there should be more memory in the guest test region than there 185 * can be pages in the guest, it will definitely cause problems. 186 */ 187 TEST_ASSERT(guest_num_pages < region_end_gfn, 188 "Requested more guest memory than address space allows.\n" 189 " guest pages: %" PRIx64 " max gfn: %" PRIx64 190 " nr_vcpus: %d wss: %" PRIx64 "]\n", 191 guest_num_pages, region_end_gfn - 1, nr_vcpus, vcpu_memory_bytes); 192 193 args->gpa = (region_end_gfn - guest_num_pages - 1) * args->guest_page_size; 194 args->gpa = align_down(args->gpa, backing_src_pagesz); 195 #ifdef __s390x__ 196 /* Align to 1M (segment size) */ 197 args->gpa = align_down(args->gpa, 1 << 20); 198 #endif 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 memstress_destroy_vm(struct kvm_vm * vm)230 void memstress_destroy_vm(struct kvm_vm *vm) 231 { 232 kvm_vm_free(vm); 233 } 234 memstress_set_write_percent(struct kvm_vm * vm,uint32_t write_percent)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 memstress_set_random_seed(struct kvm_vm * vm,uint32_t random_seed)241 void memstress_set_random_seed(struct kvm_vm *vm, uint32_t random_seed) 242 { 243 memstress_args.random_seed = random_seed; 244 sync_global_to_guest(vm, memstress_args.random_seed); 245 } 246 memstress_set_random_access(struct kvm_vm * vm,bool random_access)247 void memstress_set_random_access(struct kvm_vm *vm, bool random_access) 248 { 249 memstress_args.random_access = random_access; 250 sync_global_to_guest(vm, memstress_args.random_access); 251 } 252 memstress_nested_pages(int nr_vcpus)253 uint64_t __weak memstress_nested_pages(int nr_vcpus) 254 { 255 return 0; 256 } 257 memstress_setup_nested(struct kvm_vm * vm,int nr_vcpus,struct kvm_vcpu ** vcpus)258 void __weak memstress_setup_nested(struct kvm_vm *vm, int nr_vcpus, struct kvm_vcpu **vcpus) 259 { 260 pr_info("%s() not support on this architecture, skipping.\n", __func__); 261 exit(KSFT_SKIP); 262 } 263 vcpu_thread_main(void * data)264 static void *vcpu_thread_main(void *data) 265 { 266 struct vcpu_thread *vcpu = data; 267 int vcpu_idx = vcpu->vcpu_idx; 268 269 if (memstress_args.pin_vcpus) 270 kvm_pin_this_task_to_pcpu(memstress_args.vcpu_to_pcpu[vcpu_idx]); 271 272 WRITE_ONCE(vcpu->running, true); 273 274 /* 275 * Wait for all vCPU threads to be up and running before calling the test- 276 * provided vCPU thread function. This prevents thread creation (which 277 * requires taking the mmap_sem in write mode) from interfering with the 278 * guest faulting in its memory. 279 */ 280 while (!READ_ONCE(all_vcpu_threads_running)) 281 ; 282 283 vcpu_thread_fn(&memstress_args.vcpu_args[vcpu_idx]); 284 285 return NULL; 286 } 287 memstress_start_vcpu_threads(int nr_vcpus,void (* vcpu_fn)(struct memstress_vcpu_args *))288 void memstress_start_vcpu_threads(int nr_vcpus, 289 void (*vcpu_fn)(struct memstress_vcpu_args *)) 290 { 291 int i; 292 293 vcpu_thread_fn = vcpu_fn; 294 WRITE_ONCE(all_vcpu_threads_running, false); 295 WRITE_ONCE(memstress_args.stop_vcpus, false); 296 297 for (i = 0; i < nr_vcpus; i++) { 298 struct vcpu_thread *vcpu = &vcpu_threads[i]; 299 300 vcpu->vcpu_idx = i; 301 WRITE_ONCE(vcpu->running, false); 302 303 pthread_create(&vcpu->thread, NULL, vcpu_thread_main, vcpu); 304 } 305 306 for (i = 0; i < nr_vcpus; i++) { 307 while (!READ_ONCE(vcpu_threads[i].running)) 308 ; 309 } 310 311 WRITE_ONCE(all_vcpu_threads_running, true); 312 } 313 memstress_join_vcpu_threads(int nr_vcpus)314 void memstress_join_vcpu_threads(int nr_vcpus) 315 { 316 int i; 317 318 WRITE_ONCE(memstress_args.stop_vcpus, true); 319 320 for (i = 0; i < nr_vcpus; i++) 321 pthread_join(vcpu_threads[i].thread, NULL); 322 } 323