1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * KVM demand paging test 4 * Adapted from dirty_log_test.c 5 * 6 * Copyright (C) 2018, Red Hat, Inc. 7 * Copyright (C) 2019, Google, Inc. 8 */ 9 10 #define _GNU_SOURCE /* for pipe2 */ 11 12 #include <inttypes.h> 13 #include <stdio.h> 14 #include <stdlib.h> 15 #include <time.h> 16 #include <poll.h> 17 #include <pthread.h> 18 #include <linux/userfaultfd.h> 19 #include <sys/syscall.h> 20 21 #include "kvm_util.h" 22 #include "test_util.h" 23 #include "memstress.h" 24 #include "guest_modes.h" 25 #include "userfaultfd_util.h" 26 27 #ifdef __NR_userfaultfd 28 29 static int nr_vcpus = 1; 30 static uint64_t guest_percpu_mem_size = DEFAULT_PER_VCPU_MEM_SIZE; 31 32 static size_t demand_paging_size; 33 static char *guest_data_prototype; 34 35 static void vcpu_worker(struct memstress_vcpu_args *vcpu_args) 36 { 37 struct kvm_vcpu *vcpu = vcpu_args->vcpu; 38 int vcpu_idx = vcpu_args->vcpu_idx; 39 struct kvm_run *run = vcpu->run; 40 struct timespec start; 41 struct timespec ts_diff; 42 int ret; 43 44 clock_gettime(CLOCK_MONOTONIC, &start); 45 46 /* Let the guest access its memory */ 47 ret = _vcpu_run(vcpu); 48 TEST_ASSERT(ret == 0, "vcpu_run failed: %d\n", ret); 49 if (get_ucall(vcpu, NULL) != UCALL_SYNC) { 50 TEST_ASSERT(false, 51 "Invalid guest sync status: exit_reason=%s\n", 52 exit_reason_str(run->exit_reason)); 53 } 54 55 ts_diff = timespec_elapsed(start); 56 PER_VCPU_DEBUG("vCPU %d execution time: %ld.%.9lds\n", vcpu_idx, 57 ts_diff.tv_sec, ts_diff.tv_nsec); 58 } 59 60 static int handle_uffd_page_request(int uffd_mode, int uffd, 61 struct uffd_msg *msg) 62 { 63 pid_t tid = syscall(__NR_gettid); 64 uint64_t addr = msg->arg.pagefault.address; 65 struct timespec start; 66 struct timespec ts_diff; 67 int r; 68 69 clock_gettime(CLOCK_MONOTONIC, &start); 70 71 if (uffd_mode == UFFDIO_REGISTER_MODE_MISSING) { 72 struct uffdio_copy copy; 73 74 copy.src = (uint64_t)guest_data_prototype; 75 copy.dst = addr; 76 copy.len = demand_paging_size; 77 copy.mode = 0; 78 79 r = ioctl(uffd, UFFDIO_COPY, ©); 80 if (r == -1) { 81 pr_info("Failed UFFDIO_COPY in 0x%lx from thread %d with errno: %d\n", 82 addr, tid, errno); 83 return r; 84 } 85 } else if (uffd_mode == UFFDIO_REGISTER_MODE_MINOR) { 86 struct uffdio_continue cont = {0}; 87 88 cont.range.start = addr; 89 cont.range.len = demand_paging_size; 90 91 r = ioctl(uffd, UFFDIO_CONTINUE, &cont); 92 if (r == -1) { 93 pr_info("Failed UFFDIO_CONTINUE in 0x%lx from thread %d with errno: %d\n", 94 addr, tid, errno); 95 return r; 96 } 97 } else { 98 TEST_FAIL("Invalid uffd mode %d", uffd_mode); 99 } 100 101 ts_diff = timespec_elapsed(start); 102 103 PER_PAGE_DEBUG("UFFD page-in %d \t%ld ns\n", tid, 104 timespec_to_ns(ts_diff)); 105 PER_PAGE_DEBUG("Paged in %ld bytes at 0x%lx from thread %d\n", 106 demand_paging_size, addr, tid); 107 108 return 0; 109 } 110 111 struct test_params { 112 int uffd_mode; 113 useconds_t uffd_delay; 114 enum vm_mem_backing_src_type src_type; 115 bool partition_vcpu_memory_access; 116 }; 117 118 static void prefault_mem(void *alias, uint64_t len) 119 { 120 size_t p; 121 122 TEST_ASSERT(alias != NULL, "Alias required for minor faults"); 123 for (p = 0; p < (len / demand_paging_size); ++p) { 124 memcpy(alias + (p * demand_paging_size), 125 guest_data_prototype, demand_paging_size); 126 } 127 } 128 129 static void run_test(enum vm_guest_mode mode, void *arg) 130 { 131 struct test_params *p = arg; 132 struct uffd_desc **uffd_descs = NULL; 133 struct timespec start; 134 struct timespec ts_diff; 135 struct kvm_vm *vm; 136 int i; 137 138 vm = memstress_create_vm(mode, nr_vcpus, guest_percpu_mem_size, 1, 139 p->src_type, p->partition_vcpu_memory_access); 140 141 demand_paging_size = get_backing_src_pagesz(p->src_type); 142 143 guest_data_prototype = malloc(demand_paging_size); 144 TEST_ASSERT(guest_data_prototype, 145 "Failed to allocate buffer for guest data pattern"); 146 memset(guest_data_prototype, 0xAB, demand_paging_size); 147 148 if (p->uffd_mode) { 149 uffd_descs = malloc(nr_vcpus * sizeof(struct uffd_desc *)); 150 TEST_ASSERT(uffd_descs, "Memory allocation failed"); 151 152 for (i = 0; i < nr_vcpus; i++) { 153 struct memstress_vcpu_args *vcpu_args; 154 void *vcpu_hva; 155 void *vcpu_alias; 156 157 vcpu_args = &memstress_args.vcpu_args[i]; 158 159 /* Cache the host addresses of the region */ 160 vcpu_hva = addr_gpa2hva(vm, vcpu_args->gpa); 161 vcpu_alias = addr_gpa2alias(vm, vcpu_args->gpa); 162 163 prefault_mem(vcpu_alias, 164 vcpu_args->pages * memstress_args.guest_page_size); 165 166 /* 167 * Set up user fault fd to handle demand paging 168 * requests. 169 */ 170 uffd_descs[i] = uffd_setup_demand_paging( 171 p->uffd_mode, p->uffd_delay, vcpu_hva, 172 vcpu_args->pages * memstress_args.guest_page_size, 173 &handle_uffd_page_request); 174 } 175 } 176 177 pr_info("Finished creating vCPUs and starting uffd threads\n"); 178 179 clock_gettime(CLOCK_MONOTONIC, &start); 180 memstress_start_vcpu_threads(nr_vcpus, vcpu_worker); 181 pr_info("Started all vCPUs\n"); 182 183 memstress_join_vcpu_threads(nr_vcpus); 184 ts_diff = timespec_elapsed(start); 185 pr_info("All vCPU threads joined\n"); 186 187 if (p->uffd_mode) { 188 /* Tell the user fault fd handler threads to quit */ 189 for (i = 0; i < nr_vcpus; i++) 190 uffd_stop_demand_paging(uffd_descs[i]); 191 } 192 193 pr_info("Total guest execution time: %ld.%.9lds\n", 194 ts_diff.tv_sec, ts_diff.tv_nsec); 195 pr_info("Overall demand paging rate: %f pgs/sec\n", 196 memstress_args.vcpu_args[0].pages * nr_vcpus / 197 ((double)ts_diff.tv_sec + (double)ts_diff.tv_nsec / 100000000.0)); 198 199 memstress_destroy_vm(vm); 200 201 free(guest_data_prototype); 202 if (p->uffd_mode) 203 free(uffd_descs); 204 } 205 206 static void help(char *name) 207 { 208 puts(""); 209 printf("usage: %s [-h] [-m vm_mode] [-u uffd_mode] [-d uffd_delay_usec]\n" 210 " [-b memory] [-s type] [-v vcpus] [-o]\n", name); 211 guest_modes_help(); 212 printf(" -u: use userfaultfd to handle vCPU page faults. Mode is a\n" 213 " UFFD registration mode: 'MISSING' or 'MINOR'.\n"); 214 printf(" -d: add a delay in usec to the User Fault\n" 215 " FD handler to simulate demand paging\n" 216 " overheads. Ignored without -u.\n"); 217 printf(" -b: specify the size of the memory region which should be\n" 218 " demand paged by each vCPU. e.g. 10M or 3G.\n" 219 " Default: 1G\n"); 220 backing_src_help("-s"); 221 printf(" -v: specify the number of vCPUs to run.\n"); 222 printf(" -o: Overlap guest memory accesses instead of partitioning\n" 223 " them into a separate region of memory for each vCPU.\n"); 224 puts(""); 225 exit(0); 226 } 227 228 int main(int argc, char *argv[]) 229 { 230 int max_vcpus = kvm_check_cap(KVM_CAP_MAX_VCPUS); 231 struct test_params p = { 232 .src_type = DEFAULT_VM_MEM_SRC, 233 .partition_vcpu_memory_access = true, 234 }; 235 int opt; 236 237 guest_modes_append_default(); 238 239 while ((opt = getopt(argc, argv, "hm:u:d:b:s:v:o")) != -1) { 240 switch (opt) { 241 case 'm': 242 guest_modes_cmdline(optarg); 243 break; 244 case 'u': 245 if (!strcmp("MISSING", optarg)) 246 p.uffd_mode = UFFDIO_REGISTER_MODE_MISSING; 247 else if (!strcmp("MINOR", optarg)) 248 p.uffd_mode = UFFDIO_REGISTER_MODE_MINOR; 249 TEST_ASSERT(p.uffd_mode, "UFFD mode must be 'MISSING' or 'MINOR'."); 250 break; 251 case 'd': 252 p.uffd_delay = strtoul(optarg, NULL, 0); 253 TEST_ASSERT(p.uffd_delay >= 0, "A negative UFFD delay is not supported."); 254 break; 255 case 'b': 256 guest_percpu_mem_size = parse_size(optarg); 257 break; 258 case 's': 259 p.src_type = parse_backing_src_type(optarg); 260 break; 261 case 'v': 262 nr_vcpus = atoi_positive("Number of vCPUs", optarg); 263 TEST_ASSERT(nr_vcpus <= max_vcpus, 264 "Invalid number of vcpus, must be between 1 and %d", max_vcpus); 265 break; 266 case 'o': 267 p.partition_vcpu_memory_access = false; 268 break; 269 case 'h': 270 default: 271 help(argv[0]); 272 break; 273 } 274 } 275 276 if (p.uffd_mode == UFFDIO_REGISTER_MODE_MINOR && 277 !backing_src_is_shared(p.src_type)) { 278 TEST_FAIL("userfaultfd MINOR mode requires shared memory; pick a different -s"); 279 } 280 281 for_each_guest_mode(run_test, &p); 282 283 return 0; 284 } 285 286 #else /* __NR_userfaultfd */ 287 288 #warning "missing __NR_userfaultfd definition" 289 290 int main(void) 291 { 292 print_skip("__NR_userfaultfd must be present for userfaultfd test"); 293 return KSFT_SKIP; 294 } 295 296 #endif /* __NR_userfaultfd */ 297