1 // SPDX-License-Identifier: GPL-2.0 2 #include <stdio.h> 3 #include <stdlib.h> 4 #include <pthread.h> 5 #include <semaphore.h> 6 #include <sys/types.h> 7 #include <signal.h> 8 #include <errno.h> 9 #include <linux/bitmap.h> 10 #include <linux/bitops.h> 11 #include <linux/atomic.h> 12 #include <linux/sizes.h> 13 14 #include "kvm_util.h" 15 #include "test_util.h" 16 #include "guest_modes.h" 17 #include "processor.h" 18 19 static void guest_code(uint64_t start_gpa, uint64_t end_gpa, uint64_t stride) 20 { 21 uint64_t gpa; 22 23 for (;;) { 24 for (gpa = start_gpa; gpa < end_gpa; gpa += stride) 25 *((volatile uint64_t *)gpa) = gpa; 26 GUEST_SYNC(0); 27 } 28 } 29 30 struct vcpu_info { 31 struct kvm_vcpu *vcpu; 32 uint64_t start_gpa; 33 uint64_t end_gpa; 34 }; 35 36 static int nr_vcpus; 37 static atomic_t rendezvous; 38 39 static void rendezvous_with_boss(void) 40 { 41 int orig = atomic_read(&rendezvous); 42 43 if (orig > 0) { 44 atomic_dec_and_test(&rendezvous); 45 while (atomic_read(&rendezvous) > 0) 46 cpu_relax(); 47 } else { 48 atomic_inc(&rendezvous); 49 while (atomic_read(&rendezvous) < 0) 50 cpu_relax(); 51 } 52 } 53 54 static void run_vcpu(struct kvm_vcpu *vcpu) 55 { 56 vcpu_run(vcpu); 57 TEST_ASSERT_EQ(get_ucall(vcpu, NULL), UCALL_SYNC); 58 } 59 60 static void *vcpu_worker(void *data) 61 { 62 struct vcpu_info *info = data; 63 struct kvm_vcpu *vcpu = info->vcpu; 64 struct kvm_vm *vm = vcpu->vm; 65 struct kvm_sregs sregs; 66 67 vcpu_args_set(vcpu, 3, info->start_gpa, info->end_gpa, vm->page_size); 68 69 rendezvous_with_boss(); 70 71 run_vcpu(vcpu); 72 rendezvous_with_boss(); 73 vcpu_sregs_get(vcpu, &sregs); 74 #ifdef __x86_64__ 75 /* Toggle CR0.WP to trigger a MMU context reset. */ 76 sregs.cr0 ^= X86_CR0_WP; 77 #endif 78 vcpu_sregs_set(vcpu, &sregs); 79 rendezvous_with_boss(); 80 81 run_vcpu(vcpu); 82 rendezvous_with_boss(); 83 84 return NULL; 85 } 86 87 static pthread_t *spawn_workers(struct kvm_vm *vm, struct kvm_vcpu **vcpus, 88 uint64_t start_gpa, uint64_t end_gpa) 89 { 90 struct vcpu_info *info; 91 uint64_t gpa, nr_bytes; 92 pthread_t *threads; 93 int i; 94 95 threads = malloc(nr_vcpus * sizeof(*threads)); 96 TEST_ASSERT(threads, "Failed to allocate vCPU threads"); 97 98 info = malloc(nr_vcpus * sizeof(*info)); 99 TEST_ASSERT(info, "Failed to allocate vCPU gpa ranges"); 100 101 nr_bytes = ((end_gpa - start_gpa) / nr_vcpus) & 102 ~((uint64_t)vm->page_size - 1); 103 TEST_ASSERT(nr_bytes, "C'mon, no way you have %d CPUs", nr_vcpus); 104 105 for (i = 0, gpa = start_gpa; i < nr_vcpus; i++, gpa += nr_bytes) { 106 info[i].vcpu = vcpus[i]; 107 info[i].start_gpa = gpa; 108 info[i].end_gpa = gpa + nr_bytes; 109 pthread_create(&threads[i], NULL, vcpu_worker, &info[i]); 110 } 111 return threads; 112 } 113 114 static void rendezvous_with_vcpus(struct timespec *time, const char *name) 115 { 116 int i, rendezvoused; 117 118 pr_info("Waiting for vCPUs to finish %s...\n", name); 119 120 rendezvoused = atomic_read(&rendezvous); 121 for (i = 0; abs(rendezvoused) != 1; i++) { 122 usleep(100); 123 if (!(i & 0x3f)) 124 pr_info("\r%d vCPUs haven't rendezvoused...", 125 abs(rendezvoused) - 1); 126 rendezvoused = atomic_read(&rendezvous); 127 } 128 129 clock_gettime(CLOCK_MONOTONIC, time); 130 131 /* Release the vCPUs after getting the time of the previous action. */ 132 pr_info("\rAll vCPUs finished %s, releasing...\n", name); 133 if (rendezvoused > 0) 134 atomic_set(&rendezvous, -nr_vcpus - 1); 135 else 136 atomic_set(&rendezvous, nr_vcpus + 1); 137 } 138 139 static void calc_default_nr_vcpus(void) 140 { 141 cpu_set_t possible_mask; 142 int r; 143 144 r = sched_getaffinity(0, sizeof(possible_mask), &possible_mask); 145 TEST_ASSERT(!r, "sched_getaffinity failed, errno = %d (%s)", 146 errno, strerror(errno)); 147 148 nr_vcpus = CPU_COUNT(&possible_mask) * 3/4; 149 TEST_ASSERT(nr_vcpus > 0, "Uh, no CPUs?"); 150 } 151 152 int main(int argc, char *argv[]) 153 { 154 /* 155 * Skip the first 4gb and slot0. slot0 maps <1gb and is used to back 156 * the guest's code, stack, and page tables. Because selftests creates 157 * an IRQCHIP, a.k.a. a local APIC, KVM creates an internal memslot 158 * just below the 4gb boundary. This test could create memory at 159 * 1gb-3gb,but it's simpler to skip straight to 4gb. 160 */ 161 const uint64_t start_gpa = SZ_4G; 162 const int first_slot = 1; 163 164 struct timespec time_start, time_run1, time_reset, time_run2; 165 uint64_t max_gpa, gpa, slot_size, max_mem, i; 166 int max_slots, slot, opt, fd; 167 bool hugepages = false; 168 struct kvm_vcpu **vcpus; 169 pthread_t *threads; 170 struct kvm_vm *vm; 171 void *mem; 172 173 /* 174 * Default to 2gb so that maxing out systems with MAXPHADDR=46, which 175 * are quite common for x86, requires changing only max_mem (KVM allows 176 * 32k memslots, 32k * 2gb == ~64tb of guest memory). 177 */ 178 slot_size = SZ_2G; 179 180 max_slots = kvm_check_cap(KVM_CAP_NR_MEMSLOTS); 181 TEST_ASSERT(max_slots > first_slot, "KVM is broken"); 182 183 /* All KVM MMUs should be able to survive a 128gb guest. */ 184 max_mem = 128ull * SZ_1G; 185 186 calc_default_nr_vcpus(); 187 188 while ((opt = getopt(argc, argv, "c:h:m:s:H")) != -1) { 189 switch (opt) { 190 case 'c': 191 nr_vcpus = atoi_positive("Number of vCPUs", optarg); 192 break; 193 case 'm': 194 max_mem = 1ull * atoi_positive("Memory size", optarg) * SZ_1G; 195 break; 196 case 's': 197 slot_size = 1ull * atoi_positive("Slot size", optarg) * SZ_1G; 198 break; 199 case 'H': 200 hugepages = true; 201 break; 202 case 'h': 203 default: 204 printf("usage: %s [-c nr_vcpus] [-m max_mem_in_gb] [-s slot_size_in_gb] [-H]\n", argv[0]); 205 exit(1); 206 } 207 } 208 209 vcpus = malloc(nr_vcpus * sizeof(*vcpus)); 210 TEST_ASSERT(vcpus, "Failed to allocate vCPU array"); 211 212 vm = vm_create_with_vcpus(nr_vcpus, guest_code, vcpus); 213 214 max_gpa = vm->max_gfn << vm->page_shift; 215 TEST_ASSERT(max_gpa > (4 * slot_size), "MAXPHYADDR <4gb "); 216 217 fd = kvm_memfd_alloc(slot_size, hugepages); 218 mem = mmap(NULL, slot_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); 219 TEST_ASSERT(mem != MAP_FAILED, "mmap() failed"); 220 221 TEST_ASSERT(!madvise(mem, slot_size, MADV_NOHUGEPAGE), "madvise() failed"); 222 223 /* Pre-fault the memory to avoid taking mmap_sem on guest page faults. */ 224 for (i = 0; i < slot_size; i += vm->page_size) 225 ((uint8_t *)mem)[i] = 0xaa; 226 227 gpa = 0; 228 for (slot = first_slot; slot < max_slots; slot++) { 229 gpa = start_gpa + ((slot - first_slot) * slot_size); 230 if (gpa + slot_size > max_gpa) 231 break; 232 233 if ((gpa - start_gpa) >= max_mem) 234 break; 235 236 vm_set_user_memory_region(vm, slot, 0, gpa, slot_size, mem); 237 238 #ifdef __x86_64__ 239 /* Identity map memory in the guest using 1gb pages. */ 240 for (i = 0; i < slot_size; i += SZ_1G) 241 __virt_pg_map(vm, gpa + i, gpa + i, PG_LEVEL_1G); 242 #else 243 for (i = 0; i < slot_size; i += vm->page_size) 244 virt_pg_map(vm, gpa + i, gpa + i); 245 #endif 246 } 247 248 atomic_set(&rendezvous, nr_vcpus + 1); 249 threads = spawn_workers(vm, vcpus, start_gpa, gpa); 250 251 free(vcpus); 252 vcpus = NULL; 253 254 pr_info("Running with %lugb of guest memory and %u vCPUs\n", 255 (gpa - start_gpa) / SZ_1G, nr_vcpus); 256 257 rendezvous_with_vcpus(&time_start, "spawning"); 258 rendezvous_with_vcpus(&time_run1, "run 1"); 259 rendezvous_with_vcpus(&time_reset, "reset"); 260 rendezvous_with_vcpus(&time_run2, "run 2"); 261 262 time_run2 = timespec_sub(time_run2, time_reset); 263 time_reset = timespec_sub(time_reset, time_run1); 264 time_run1 = timespec_sub(time_run1, time_start); 265 266 pr_info("run1 = %ld.%.9lds, reset = %ld.%.9lds, run2 = %ld.%.9lds\n", 267 time_run1.tv_sec, time_run1.tv_nsec, 268 time_reset.tv_sec, time_reset.tv_nsec, 269 time_run2.tv_sec, time_run2.tv_nsec); 270 271 /* 272 * Delete even numbered slots (arbitrary) and unmap the first half of 273 * the backing (also arbitrary) to verify KVM correctly drops all 274 * references to the removed regions. 275 */ 276 for (slot = (slot - 1) & ~1ull; slot >= first_slot; slot -= 2) 277 vm_set_user_memory_region(vm, slot, 0, 0, 0, NULL); 278 279 munmap(mem, slot_size / 2); 280 281 /* Sanity check that the vCPUs actually ran. */ 282 for (i = 0; i < nr_vcpus; i++) 283 pthread_join(threads[i], NULL); 284 285 /* 286 * Deliberately exit without deleting the remaining memslots or closing 287 * kvm_fd to test cleanup via mmu_notifier.release. 288 */ 289 } 290