xref: /openbmc/linux/tools/testing/selftests/kvm/aarch64/arch_timer.c (revision c900529f3d9161bfde5cca0754f83b4d3c3e0220)
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
guest_configure_timer_action(struct test_vcpu_shared_data * shared_data)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  
guest_validate_irq(unsigned int intid,struct test_vcpu_shared_data * shared_data)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%llx, cval = 0x%llx, xcnt_diff_us = 0x%llx",
162  		       xcnt, cval, xcnt_diff_us);
163  	__GUEST_ASSERT(xctl & CTL_ISTATUS, "xcnt = 0x%llx", xcnt);
164  
165  	WRITE_ONCE(shared_data->nr_iter, shared_data->nr_iter + 1);
166  }
167  
guest_irq_handler(struct ex_regs * regs)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  
guest_run_stage(struct test_vcpu_shared_data * shared_data,enum guest_stage stage)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  
guest_code(void)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  
test_vcpu_run(void * arg)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\n");
252  	}
253  
254  	return NULL;
255  }
256  
test_get_pcpu(void)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  
test_migrate_vcpu(unsigned int vcpu_idx)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\n",
291  		    vcpu_idx, new_pcpu, ret);
292  
293  	return ret;
294  }
295  
test_vcpu_migration(void * arg)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  
test_run(struct kvm_vm * vm)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\n");
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\n", 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\n");
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  
test_init_timer_irq(struct kvm_vm * vm)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  
test_vm_create(void)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\n");
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  
test_vm_cleanup(struct kvm_vm * vm)403  static void test_vm_cleanup(struct kvm_vm *vm)
404  {
405  	close(gic_fd);
406  	kvm_vm_free(vm);
407  }
408  
test_print_help(char * name)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  
parse_args(int argc,char * argv[])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  
main(int argc,char * argv[])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  }
481