tools/testing/selftests/kvm/aarch64/arch_timer.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * arch_timer.c - Tests the aarch64 timer IRQ functionality
   4  *
   5  * The test validates both the virtual and physical timer IRQs using
   6  * CVAL and TVAL registers. This consitutes the four stages in the test.
   7  * The guest's main thread configures the timer interrupt for a stage
   8  * and waits for it to fire, with a timeout equal to the timer period.
   9  * It asserts that the timeout doesn't exceed the timer period.
  10  *
  11  * On the other hand, upon receipt of an interrupt, the guest's interrupt
  12  * handler validates the interrupt by checking if the architectural state
  13  * is in compliance with the specifications.
  14  *
  15  * The test provides command-line options to configure the timer's
  16  * period (-p), number of vCPUs (-n), and iterations per stage (-i).
  17  * To stress-test the timer stack even more, an option to migrate the
  18  * vCPUs across pCPUs (-m), at a particular rate, is also provided.
  19  *
  20  * Copyright (c) 2021, Google LLC.
  21  */
  22 #define _GNU_SOURCE
  23
  24 #include <stdlib.h>
  25 #include <pthread.h>
  26 #include <linux/kvm.h>
  27 #include <linux/sizes.h>
  28 #include <linux/bitmap.h>
  29 #include <sys/sysinfo.h>
  30
  31 #include "kvm_util.h"
  32 #include "processor.h"
  33 #include "delay.h"
  34 #include "arch_timer.h"
  35 #include "gic.h"
  36 #include "vgic.h"
  37
  38 #define NR_VCPUS_DEF                    4
  39 #define NR_TEST_ITERS_DEF               5
  40 #define TIMER_TEST_PERIOD_MS_DEF        10
  41 #define TIMER_TEST_ERR_MARGIN_US        100
  42 #define TIMER_TEST_MIGRATION_FREQ_MS    2
  43
  44 struct test_args {
  45         int nr_vcpus;
  46         int nr_iter;
  47         int timer_period_ms;
  48         int migration_freq_ms;
  49         struct kvm_arm_counter_offset offset;
  50 };
  51
  52 static struct test_args test_args = {
  53         .nr_vcpus = NR_VCPUS_DEF,
  54         .nr_iter = NR_TEST_ITERS_DEF,
  55         .timer_period_ms = TIMER_TEST_PERIOD_MS_DEF,
  56         .migration_freq_ms = TIMER_TEST_MIGRATION_FREQ_MS,
  57         .offset = { .reserved = 1 },
  58 };
  59
  60 #define msecs_to_usecs(msec)            ((msec) * 1000LL)
  61
  62 #define GICD_BASE_GPA                   0x8000000ULL
  63 #define GICR_BASE_GPA                   0x80A0000ULL
  64
  65 enum guest_stage {
  66         GUEST_STAGE_VTIMER_CVAL = 1,
  67         GUEST_STAGE_VTIMER_TVAL,
  68         GUEST_STAGE_PTIMER_CVAL,
  69         GUEST_STAGE_PTIMER_TVAL,
  70         GUEST_STAGE_MAX,
  71 };
  72
  73 /* Shared variables between host and guest */
  74 struct test_vcpu_shared_data {
  75         int nr_iter;
  76         enum guest_stage guest_stage;
  77         uint64_t xcnt;
  78 };
  79
  80 static struct kvm_vcpu *vcpus[KVM_MAX_VCPUS];
  81 static pthread_t pt_vcpu_run[KVM_MAX_VCPUS];
  82 static struct test_vcpu_shared_data vcpu_shared_data[KVM_MAX_VCPUS];
  83
  84 static int vtimer_irq, ptimer_irq;
  85
  86 static unsigned long *vcpu_done_map;
  87 static pthread_mutex_t vcpu_done_map_lock;
  88
  89 static void
  90 guest_configure_timer_action(struct test_vcpu_shared_data *shared_data)
  91 {
  92         switch (shared_data->guest_stage) {
  93         case GUEST_STAGE_VTIMER_CVAL:
  94                 timer_set_next_cval_ms(VIRTUAL, test_args.timer_period_ms);
  95                 shared_data->xcnt = timer_get_cntct(VIRTUAL);
  96                 timer_set_ctl(VIRTUAL, CTL_ENABLE);
  97                 break;
  98         case GUEST_STAGE_VTIMER_TVAL:
  99                 timer_set_next_tval_ms(VIRTUAL, test_args.timer_period_ms);
 100                 shared_data->xcnt = timer_get_cntct(VIRTUAL);
 101                 timer_set_ctl(VIRTUAL, CTL_ENABLE);
 102                 break;
 103         case GUEST_STAGE_PTIMER_CVAL:
 104                 timer_set_next_cval_ms(PHYSICAL, test_args.timer_period_ms);
 105                 shared_data->xcnt = timer_get_cntct(PHYSICAL);
 106                 timer_set_ctl(PHYSICAL, CTL_ENABLE);
 107                 break;
 108         case GUEST_STAGE_PTIMER_TVAL:
 109                 timer_set_next_tval_ms(PHYSICAL, test_args.timer_period_ms);
 110                 shared_data->xcnt = timer_get_cntct(PHYSICAL);
 111                 timer_set_ctl(PHYSICAL, CTL_ENABLE);
 112                 break;
 113         default:
 114                 GUEST_ASSERT(0);
 115         }
 116 }
 117
 118 static void guest_validate_irq(unsigned int intid,
 119                                 struct test_vcpu_shared_data *shared_data)
 120 {
 121         enum guest_stage stage = shared_data->guest_stage;
 122         uint64_t xcnt = 0, xcnt_diff_us, cval = 0;
 123         unsigned long xctl = 0;
 124         unsigned int timer_irq = 0;
 125         unsigned int accessor;
 126
 127         if (intid == IAR_SPURIOUS)
 128                 return;
 129
 130         switch (stage) {
 131         case GUEST_STAGE_VTIMER_CVAL:
 132         case GUEST_STAGE_VTIMER_TVAL:
 133                 accessor = VIRTUAL;
 134                 timer_irq = vtimer_irq;
 135                 break;
 136         case GUEST_STAGE_PTIMER_CVAL:
 137         case GUEST_STAGE_PTIMER_TVAL:
 138                 accessor = PHYSICAL;
 139                 timer_irq = ptimer_irq;
 140                 break;
 141         default:
 142                 GUEST_ASSERT(0);
 143                 return;
 144         }
 145
 146         xctl = timer_get_ctl(accessor);
 147         if ((xctl & CTL_IMASK) || !(xctl & CTL_ENABLE))
 148                 return;
 149
 150         timer_set_ctl(accessor, CTL_IMASK);
 151         xcnt = timer_get_cntct(accessor);
 152         cval = timer_get_cval(accessor);
 153
 154         xcnt_diff_us = cycles_to_usec(xcnt - shared_data->xcnt);
 155
 156         /* Make sure we are dealing with the correct timer IRQ */
 157         GUEST_ASSERT_EQ(intid, timer_irq);
 158
 159         /* Basic 'timer condition met' check */
 160         __GUEST_ASSERT(xcnt >= cval,
 161                        "xcnt = 0x%lx, cval = 0x%lx, xcnt_diff_us = 0x%lx",
 162                        xcnt, cval, xcnt_diff_us);
 163         __GUEST_ASSERT(xctl & CTL_ISTATUS, "xctl = 0x%lx", xctl);
 164
 165         WRITE_ONCE(shared_data->nr_iter, shared_data->nr_iter + 1);
 166 }
 167
 168 static void guest_irq_handler(struct ex_regs *regs)
 169 {
 170         unsigned int intid = gic_get_and_ack_irq();
 171         uint32_t cpu = guest_get_vcpuid();
 172         struct test_vcpu_shared_data *shared_data = &vcpu_shared_data[cpu];
 173
 174         guest_validate_irq(intid, shared_data);
 175
 176         gic_set_eoi(intid);
 177 }
 178
 179 static void guest_run_stage(struct test_vcpu_shared_data *shared_data,
 180                                 enum guest_stage stage)
 181 {
 182         uint32_t irq_iter, config_iter;
 183
 184         shared_data->guest_stage = stage;
 185         shared_data->nr_iter = 0;
 186
 187         for (config_iter = 0; config_iter < test_args.nr_iter; config_iter++) {
 188                 /* Setup the next interrupt */
 189                 guest_configure_timer_action(shared_data);
 190
 191                 /* Setup a timeout for the interrupt to arrive */
 192                 udelay(msecs_to_usecs(test_args.timer_period_ms) +
 193                         TIMER_TEST_ERR_MARGIN_US);
 194
 195                 irq_iter = READ_ONCE(shared_data->nr_iter);
 196                 GUEST_ASSERT_EQ(config_iter + 1, irq_iter);
 197         }
 198 }
 199
 200 static void guest_code(void)
 201 {
 202         uint32_t cpu = guest_get_vcpuid();
 203         struct test_vcpu_shared_data *shared_data = &vcpu_shared_data[cpu];
 204
 205         local_irq_disable();
 206
 207         gic_init(GIC_V3, test_args.nr_vcpus,
 208                 (void *)GICD_BASE_GPA, (void *)GICR_BASE_GPA);
 209
 210         timer_set_ctl(VIRTUAL, CTL_IMASK);
 211         timer_set_ctl(PHYSICAL, CTL_IMASK);
 212
 213         gic_irq_enable(vtimer_irq);
 214         gic_irq_enable(ptimer_irq);
 215         local_irq_enable();
 216
 217         guest_run_stage(shared_data, GUEST_STAGE_VTIMER_CVAL);
 218         guest_run_stage(shared_data, GUEST_STAGE_VTIMER_TVAL);
 219         guest_run_stage(shared_data, GUEST_STAGE_PTIMER_CVAL);
 220         guest_run_stage(shared_data, GUEST_STAGE_PTIMER_TVAL);
 221
 222         GUEST_DONE();
 223 }
 224
 225 static void *test_vcpu_run(void *arg)
 226 {
 227         unsigned int vcpu_idx = (unsigned long)arg;
 228         struct ucall uc;
 229         struct kvm_vcpu *vcpu = vcpus[vcpu_idx];
 230         struct kvm_vm *vm = vcpu->vm;
 231         struct test_vcpu_shared_data *shared_data = &vcpu_shared_data[vcpu_idx];
 232
 233         vcpu_run(vcpu);
 234
 235         /* Currently, any exit from guest is an indication of completion */
 236         pthread_mutex_lock(&vcpu_done_map_lock);
 237         __set_bit(vcpu_idx, vcpu_done_map);
 238         pthread_mutex_unlock(&vcpu_done_map_lock);
 239
 240         switch (get_ucall(vcpu, &uc)) {
 241         case UCALL_SYNC:
 242         case UCALL_DONE:
 243                 break;
 244         case UCALL_ABORT:
 245                 sync_global_from_guest(vm, *shared_data);
 246                 fprintf(stderr, "Guest assert failed,  vcpu %u; stage; %u; iter: %u\n",
 247                         vcpu_idx, shared_data->guest_stage, shared_data->nr_iter);
 248                 REPORT_GUEST_ASSERT(uc);
 249                 break;
 250         default:
 251                 TEST_FAIL("Unexpected guest exit");
 252         }
 253
 254         return NULL;
 255 }
 256
 257 static uint32_t test_get_pcpu(void)
 258 {
 259         uint32_t pcpu;
 260         unsigned int nproc_conf;
 261         cpu_set_t online_cpuset;
 262
 263         nproc_conf = get_nprocs_conf();
 264         sched_getaffinity(0, sizeof(cpu_set_t), &online_cpuset);
 265
 266         /* Randomly find an available pCPU to place a vCPU on */
 267         do {
 268                 pcpu = rand() % nproc_conf;
 269         } while (!CPU_ISSET(pcpu, &online_cpuset));
 270
 271         return pcpu;
 272 }
 273
 274 static int test_migrate_vcpu(unsigned int vcpu_idx)
 275 {
 276         int ret;
 277         cpu_set_t cpuset;
 278         uint32_t new_pcpu = test_get_pcpu();
 279
 280         CPU_ZERO(&cpuset);
 281         CPU_SET(new_pcpu, &cpuset);
 282
 283         pr_debug("Migrating vCPU: %u to pCPU: %u\n", vcpu_idx, new_pcpu);
 284
 285         ret = pthread_setaffinity_np(pt_vcpu_run[vcpu_idx],
 286                                      sizeof(cpuset), &cpuset);
 287
 288         /* Allow the error where the vCPU thread is already finished */
 289         TEST_ASSERT(ret == 0 || ret == ESRCH,
 290                     "Failed to migrate the vCPU:%u to pCPU: %u; ret: %d",
 291                     vcpu_idx, new_pcpu, ret);
 292
 293         return ret;
 294 }
 295
 296 static void *test_vcpu_migration(void *arg)
 297 {
 298         unsigned int i, n_done;
 299         bool vcpu_done;
 300
 301         do {
 302                 usleep(msecs_to_usecs(test_args.migration_freq_ms));
 303
 304                 for (n_done = 0, i = 0; i < test_args.nr_vcpus; i++) {
 305                         pthread_mutex_lock(&vcpu_done_map_lock);
 306                         vcpu_done = test_bit(i, vcpu_done_map);
 307                         pthread_mutex_unlock(&vcpu_done_map_lock);
 308
 309                         if (vcpu_done) {
 310                                 n_done++;
 311                                 continue;
 312                         }
 313
 314                         test_migrate_vcpu(i);
 315                 }
 316         } while (test_args.nr_vcpus != n_done);
 317
 318         return NULL;
 319 }
 320
 321 static void test_run(struct kvm_vm *vm)
 322 {
 323         pthread_t pt_vcpu_migration;
 324         unsigned int i;
 325         int ret;
 326
 327         pthread_mutex_init(&vcpu_done_map_lock, NULL);
 328         vcpu_done_map = bitmap_zalloc(test_args.nr_vcpus);
 329         TEST_ASSERT(vcpu_done_map, "Failed to allocate vcpu done bitmap");
 330
 331         for (i = 0; i < (unsigned long)test_args.nr_vcpus; i++) {
 332                 ret = pthread_create(&pt_vcpu_run[i], NULL, test_vcpu_run,
 333                                      (void *)(unsigned long)i);
 334                 TEST_ASSERT(!ret, "Failed to create vCPU-%d pthread", i);
 335         }
 336
 337         /* Spawn a thread to control the vCPU migrations */
 338         if (test_args.migration_freq_ms) {
 339                 srand(time(NULL));
 340
 341                 ret = pthread_create(&pt_vcpu_migration, NULL,
 342                                         test_vcpu_migration, NULL);
 343                 TEST_ASSERT(!ret, "Failed to create the migration pthread");
 344         }
 345
 346
 347         for (i = 0; i < test_args.nr_vcpus; i++)
 348                 pthread_join(pt_vcpu_run[i], NULL);
 349
 350         if (test_args.migration_freq_ms)
 351                 pthread_join(pt_vcpu_migration, NULL);
 352
 353         bitmap_free(vcpu_done_map);
 354 }
 355
 356 static void test_init_timer_irq(struct kvm_vm *vm)
 357 {
 358         /* Timer initid should be same for all the vCPUs, so query only vCPU-0 */
 359         vcpu_device_attr_get(vcpus[0], KVM_ARM_VCPU_TIMER_CTRL,
 360                              KVM_ARM_VCPU_TIMER_IRQ_PTIMER, &ptimer_irq);
 361         vcpu_device_attr_get(vcpus[0], KVM_ARM_VCPU_TIMER_CTRL,
 362                              KVM_ARM_VCPU_TIMER_IRQ_VTIMER, &vtimer_irq);
 363
 364         sync_global_to_guest(vm, ptimer_irq);
 365         sync_global_to_guest(vm, vtimer_irq);
 366
 367         pr_debug("ptimer_irq: %d; vtimer_irq: %d\n", ptimer_irq, vtimer_irq);
 368 }
 369
 370 static int gic_fd;
 371
 372 static struct kvm_vm *test_vm_create(void)
 373 {
 374         struct kvm_vm *vm;
 375         unsigned int i;
 376         int nr_vcpus = test_args.nr_vcpus;
 377
 378         vm = vm_create_with_vcpus(nr_vcpus, guest_code, vcpus);
 379
 380         vm_init_descriptor_tables(vm);
 381         vm_install_exception_handler(vm, VECTOR_IRQ_CURRENT, guest_irq_handler);
 382
 383         if (!test_args.offset.reserved) {
 384                 if (kvm_has_cap(KVM_CAP_COUNTER_OFFSET))
 385                         vm_ioctl(vm, KVM_ARM_SET_COUNTER_OFFSET, &test_args.offset);
 386                 else
 387                         TEST_FAIL("no support for global offset");
 388         }
 389
 390         for (i = 0; i < nr_vcpus; i++)
 391                 vcpu_init_descriptor_tables(vcpus[i]);
 392
 393         test_init_timer_irq(vm);
 394         gic_fd = vgic_v3_setup(vm, nr_vcpus, 64, GICD_BASE_GPA, GICR_BASE_GPA);
 395         __TEST_REQUIRE(gic_fd >= 0, "Failed to create vgic-v3");
 396
 397         /* Make all the test's cmdline args visible to the guest */
 398         sync_global_to_guest(vm, test_args);
 399
 400         return vm;
 401 }
 402
 403 static void test_vm_cleanup(struct kvm_vm *vm)
 404 {
 405         close(gic_fd);
 406         kvm_vm_free(vm);
 407 }
 408
 409 static void test_print_help(char *name)
 410 {
 411         pr_info("Usage: %s [-h] [-n nr_vcpus] [-i iterations] [-p timer_period_ms]\n",
 412                 name);
 413         pr_info("\t-n: Number of vCPUs to configure (default: %u; max: %u)\n",
 414                 NR_VCPUS_DEF, KVM_MAX_VCPUS);
 415         pr_info("\t-i: Number of iterations per stage (default: %u)\n",
 416                 NR_TEST_ITERS_DEF);
 417         pr_info("\t-p: Periodicity (in ms) of the guest timer (default: %u)\n",
 418                 TIMER_TEST_PERIOD_MS_DEF);
 419         pr_info("\t-m: Frequency (in ms) of vCPUs to migrate to different pCPU. 0 to turn off (default: %u)\n",
 420                 TIMER_TEST_MIGRATION_FREQ_MS);
 421         pr_info("\t-o: Counter offset (in counter cycles, default: 0)\n");
 422         pr_info("\t-h: print this help screen\n");
 423 }
 424
 425 static bool parse_args(int argc, char *argv[])
 426 {
 427         int opt;
 428
 429         while ((opt = getopt(argc, argv, "hn:i:p:m:o:")) != -1) {
 430                 switch (opt) {
 431                 case 'n':
 432                         test_args.nr_vcpus = atoi_positive("Number of vCPUs", optarg);
 433                         if (test_args.nr_vcpus > KVM_MAX_VCPUS) {
 434                                 pr_info("Max allowed vCPUs: %u\n",
 435                                         KVM_MAX_VCPUS);
 436                                 goto err;
 437                         }
 438                         break;
 439                 case 'i':
 440                         test_args.nr_iter = atoi_positive("Number of iterations", optarg);
 441                         break;
 442                 case 'p':
 443                         test_args.timer_period_ms = atoi_positive("Periodicity", optarg);
 444                         break;
 445                 case 'm':
 446                         test_args.migration_freq_ms = atoi_non_negative("Frequency", optarg);
 447                         break;
 448                 case 'o':
 449                         test_args.offset.counter_offset = strtol(optarg, NULL, 0);
 450                         test_args.offset.reserved = 0;
 451                         break;
 452                 case 'h':
 453                 default:
 454                         goto err;
 455                 }
 456         }
 457
 458         return true;
 459
 460 err:
 461         test_print_help(argv[0]);
 462         return false;
 463 }
 464
 465 int main(int argc, char *argv[])
 466 {
 467         struct kvm_vm *vm;
 468
 469         if (!parse_args(argc, argv))
 470                 exit(KSFT_SKIP);
 471
 472         __TEST_REQUIRE(!test_args.migration_freq_ms || get_nprocs() >= 2,
 473                        "At least two physical CPUs needed for vCPU migration");
 474
 475         vm = test_vm_create();
 476         test_run(vm);
 477         test_vm_cleanup(vm);
 478
 479         return 0;
 480 }