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 
23 #define _GNU_SOURCE
24 
25 #include <stdlib.h>
26 #include <pthread.h>
27 #include <linux/kvm.h>
28 #include <linux/sizes.h>
29 #include <linux/bitmap.h>
30 #include <sys/sysinfo.h>
31 
32 #include "kvm_util.h"
33 #include "processor.h"
34 #include "delay.h"
35 #include "arch_timer.h"
36 #include "gic.h"
37 #include "vgic.h"
38 
39 #define NR_VCPUS_DEF			4
40 #define NR_TEST_ITERS_DEF		5
41 #define TIMER_TEST_PERIOD_MS_DEF	10
42 #define TIMER_TEST_ERR_MARGIN_US	100
43 #define TIMER_TEST_MIGRATION_FREQ_MS	2
44 
45 struct test_args {
46 	int nr_vcpus;
47 	int nr_iter;
48 	int timer_period_ms;
49 	int migration_freq_ms;
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 };
58 
59 #define msecs_to_usecs(msec)		((msec) * 1000LL)
60 
61 #define GICD_BASE_GPA			0x8000000ULL
62 #define GICR_BASE_GPA			0x80A0000ULL
63 
64 enum guest_stage {
65 	GUEST_STAGE_VTIMER_CVAL = 1,
66 	GUEST_STAGE_VTIMER_TVAL,
67 	GUEST_STAGE_PTIMER_CVAL,
68 	GUEST_STAGE_PTIMER_TVAL,
69 	GUEST_STAGE_MAX,
70 };
71 
72 /* Shared variables between host and guest */
73 struct test_vcpu_shared_data {
74 	int nr_iter;
75 	enum guest_stage guest_stage;
76 	uint64_t xcnt;
77 };
78 
79 struct test_vcpu {
80 	uint32_t vcpuid;
81 	pthread_t pt_vcpu_run;
82 	struct kvm_vm *vm;
83 };
84 
85 static struct test_vcpu test_vcpu[KVM_MAX_VCPUS];
86 static struct test_vcpu_shared_data vcpu_shared_data[KVM_MAX_VCPUS];
87 
88 static int vtimer_irq, ptimer_irq;
89 
90 static unsigned long *vcpu_done_map;
91 static pthread_mutex_t vcpu_done_map_lock;
92 
93 static void
94 guest_configure_timer_action(struct test_vcpu_shared_data *shared_data)
95 {
96 	switch (shared_data->guest_stage) {
97 	case GUEST_STAGE_VTIMER_CVAL:
98 		timer_set_next_cval_ms(VIRTUAL, test_args.timer_period_ms);
99 		shared_data->xcnt = timer_get_cntct(VIRTUAL);
100 		timer_set_ctl(VIRTUAL, CTL_ENABLE);
101 		break;
102 	case GUEST_STAGE_VTIMER_TVAL:
103 		timer_set_next_tval_ms(VIRTUAL, test_args.timer_period_ms);
104 		shared_data->xcnt = timer_get_cntct(VIRTUAL);
105 		timer_set_ctl(VIRTUAL, CTL_ENABLE);
106 		break;
107 	case GUEST_STAGE_PTIMER_CVAL:
108 		timer_set_next_cval_ms(PHYSICAL, test_args.timer_period_ms);
109 		shared_data->xcnt = timer_get_cntct(PHYSICAL);
110 		timer_set_ctl(PHYSICAL, CTL_ENABLE);
111 		break;
112 	case GUEST_STAGE_PTIMER_TVAL:
113 		timer_set_next_tval_ms(PHYSICAL, test_args.timer_period_ms);
114 		shared_data->xcnt = timer_get_cntct(PHYSICAL);
115 		timer_set_ctl(PHYSICAL, CTL_ENABLE);
116 		break;
117 	default:
118 		GUEST_ASSERT(0);
119 	}
120 }
121 
122 static void guest_validate_irq(unsigned int intid,
123 				struct test_vcpu_shared_data *shared_data)
124 {
125 	enum guest_stage stage = shared_data->guest_stage;
126 	uint64_t xcnt = 0, xcnt_diff_us, cval = 0;
127 	unsigned long xctl = 0;
128 	unsigned int timer_irq = 0;
129 
130 	if (stage == GUEST_STAGE_VTIMER_CVAL ||
131 		stage == GUEST_STAGE_VTIMER_TVAL) {
132 		xctl = timer_get_ctl(VIRTUAL);
133 		timer_set_ctl(VIRTUAL, CTL_IMASK);
134 		xcnt = timer_get_cntct(VIRTUAL);
135 		cval = timer_get_cval(VIRTUAL);
136 		timer_irq = vtimer_irq;
137 	} else if (stage == GUEST_STAGE_PTIMER_CVAL ||
138 		stage == GUEST_STAGE_PTIMER_TVAL) {
139 		xctl = timer_get_ctl(PHYSICAL);
140 		timer_set_ctl(PHYSICAL, CTL_IMASK);
141 		xcnt = timer_get_cntct(PHYSICAL);
142 		cval = timer_get_cval(PHYSICAL);
143 		timer_irq = ptimer_irq;
144 	} else {
145 		GUEST_ASSERT(0);
146 	}
147 
148 	xcnt_diff_us = cycles_to_usec(xcnt - shared_data->xcnt);
149 
150 	/* Make sure we are dealing with the correct timer IRQ */
151 	GUEST_ASSERT_2(intid == timer_irq, intid, timer_irq);
152 
153 	/* Basic 'timer condition met' check */
154 	GUEST_ASSERT_3(xcnt >= cval, xcnt, cval, xcnt_diff_us);
155 	GUEST_ASSERT_1(xctl & CTL_ISTATUS, xctl);
156 }
157 
158 static void guest_irq_handler(struct ex_regs *regs)
159 {
160 	unsigned int intid = gic_get_and_ack_irq();
161 	uint32_t cpu = guest_get_vcpuid();
162 	struct test_vcpu_shared_data *shared_data = &vcpu_shared_data[cpu];
163 
164 	guest_validate_irq(intid, shared_data);
165 
166 	WRITE_ONCE(shared_data->nr_iter, shared_data->nr_iter + 1);
167 
168 	gic_set_eoi(intid);
169 }
170 
171 static void guest_run_stage(struct test_vcpu_shared_data *shared_data,
172 				enum guest_stage stage)
173 {
174 	uint32_t irq_iter, config_iter;
175 
176 	shared_data->guest_stage = stage;
177 	shared_data->nr_iter = 0;
178 
179 	for (config_iter = 0; config_iter < test_args.nr_iter; config_iter++) {
180 		/* Setup the next interrupt */
181 		guest_configure_timer_action(shared_data);
182 
183 		/* Setup a timeout for the interrupt to arrive */
184 		udelay(msecs_to_usecs(test_args.timer_period_ms) +
185 			TIMER_TEST_ERR_MARGIN_US);
186 
187 		irq_iter = READ_ONCE(shared_data->nr_iter);
188 		GUEST_ASSERT_2(config_iter + 1 == irq_iter,
189 				config_iter + 1, irq_iter);
190 	}
191 }
192 
193 static void guest_code(void)
194 {
195 	uint32_t cpu = guest_get_vcpuid();
196 	struct test_vcpu_shared_data *shared_data = &vcpu_shared_data[cpu];
197 
198 	local_irq_disable();
199 
200 	gic_init(GIC_V3, test_args.nr_vcpus,
201 		(void *)GICD_BASE_GPA, (void *)GICR_BASE_GPA);
202 
203 	timer_set_ctl(VIRTUAL, CTL_IMASK);
204 	timer_set_ctl(PHYSICAL, CTL_IMASK);
205 
206 	gic_irq_enable(vtimer_irq);
207 	gic_irq_enable(ptimer_irq);
208 	local_irq_enable();
209 
210 	guest_run_stage(shared_data, GUEST_STAGE_VTIMER_CVAL);
211 	guest_run_stage(shared_data, GUEST_STAGE_VTIMER_TVAL);
212 	guest_run_stage(shared_data, GUEST_STAGE_PTIMER_CVAL);
213 	guest_run_stage(shared_data, GUEST_STAGE_PTIMER_TVAL);
214 
215 	GUEST_DONE();
216 }
217 
218 static void *test_vcpu_run(void *arg)
219 {
220 	struct ucall uc;
221 	struct test_vcpu *vcpu = arg;
222 	struct kvm_vm *vm = vcpu->vm;
223 	uint32_t vcpuid = vcpu->vcpuid;
224 	struct test_vcpu_shared_data *shared_data = &vcpu_shared_data[vcpuid];
225 
226 	vcpu_run(vm, vcpuid);
227 
228 	/* Currently, any exit from guest is an indication of completion */
229 	pthread_mutex_lock(&vcpu_done_map_lock);
230 	set_bit(vcpuid, vcpu_done_map);
231 	pthread_mutex_unlock(&vcpu_done_map_lock);
232 
233 	switch (get_ucall(vm, vcpuid, &uc)) {
234 	case UCALL_SYNC:
235 	case UCALL_DONE:
236 		break;
237 	case UCALL_ABORT:
238 		sync_global_from_guest(vm, *shared_data);
239 		TEST_FAIL("%s at %s:%ld\n\tvalues: %lu, %lu; %lu, vcpu: %u; stage: %u; iter: %u",
240 			(const char *)uc.args[0], __FILE__, uc.args[1],
241 			uc.args[2], uc.args[3], uc.args[4], vcpuid,
242 			shared_data->guest_stage, shared_data->nr_iter);
243 		break;
244 	default:
245 		TEST_FAIL("Unexpected guest exit\n");
246 	}
247 
248 	return NULL;
249 }
250 
251 static uint32_t test_get_pcpu(void)
252 {
253 	uint32_t pcpu;
254 	unsigned int nproc_conf;
255 	cpu_set_t online_cpuset;
256 
257 	nproc_conf = get_nprocs_conf();
258 	sched_getaffinity(0, sizeof(cpu_set_t), &online_cpuset);
259 
260 	/* Randomly find an available pCPU to place a vCPU on */
261 	do {
262 		pcpu = rand() % nproc_conf;
263 	} while (!CPU_ISSET(pcpu, &online_cpuset));
264 
265 	return pcpu;
266 }
267 
268 static int test_migrate_vcpu(struct test_vcpu *vcpu)
269 {
270 	int ret;
271 	cpu_set_t cpuset;
272 	uint32_t new_pcpu = test_get_pcpu();
273 
274 	CPU_ZERO(&cpuset);
275 	CPU_SET(new_pcpu, &cpuset);
276 
277 	pr_debug("Migrating vCPU: %u to pCPU: %u\n", vcpu->vcpuid, new_pcpu);
278 
279 	ret = pthread_setaffinity_np(vcpu->pt_vcpu_run,
280 					sizeof(cpuset), &cpuset);
281 
282 	/* Allow the error where the vCPU thread is already finished */
283 	TEST_ASSERT(ret == 0 || ret == ESRCH,
284 			"Failed to migrate the vCPU:%u to pCPU: %u; ret: %d\n",
285 			vcpu->vcpuid, new_pcpu, ret);
286 
287 	return ret;
288 }
289 
290 static void *test_vcpu_migration(void *arg)
291 {
292 	unsigned int i, n_done;
293 	bool vcpu_done;
294 
295 	do {
296 		usleep(msecs_to_usecs(test_args.migration_freq_ms));
297 
298 		for (n_done = 0, i = 0; i < test_args.nr_vcpus; i++) {
299 			pthread_mutex_lock(&vcpu_done_map_lock);
300 			vcpu_done = test_bit(i, vcpu_done_map);
301 			pthread_mutex_unlock(&vcpu_done_map_lock);
302 
303 			if (vcpu_done) {
304 				n_done++;
305 				continue;
306 			}
307 
308 			test_migrate_vcpu(&test_vcpu[i]);
309 		}
310 	} while (test_args.nr_vcpus != n_done);
311 
312 	return NULL;
313 }
314 
315 static void test_run(struct kvm_vm *vm)
316 {
317 	int i, ret;
318 	pthread_t pt_vcpu_migration;
319 
320 	pthread_mutex_init(&vcpu_done_map_lock, NULL);
321 	vcpu_done_map = bitmap_zalloc(test_args.nr_vcpus);
322 	TEST_ASSERT(vcpu_done_map, "Failed to allocate vcpu done bitmap\n");
323 
324 	for (i = 0; i < test_args.nr_vcpus; i++) {
325 		ret = pthread_create(&test_vcpu[i].pt_vcpu_run, NULL,
326 				test_vcpu_run, &test_vcpu[i]);
327 		TEST_ASSERT(!ret, "Failed to create vCPU-%d pthread\n", i);
328 	}
329 
330 	/* Spawn a thread to control the vCPU migrations */
331 	if (test_args.migration_freq_ms) {
332 		srand(time(NULL));
333 
334 		ret = pthread_create(&pt_vcpu_migration, NULL,
335 					test_vcpu_migration, NULL);
336 		TEST_ASSERT(!ret, "Failed to create the migration pthread\n");
337 	}
338 
339 
340 	for (i = 0; i < test_args.nr_vcpus; i++)
341 		pthread_join(test_vcpu[i].pt_vcpu_run, NULL);
342 
343 	if (test_args.migration_freq_ms)
344 		pthread_join(pt_vcpu_migration, NULL);
345 
346 	bitmap_free(vcpu_done_map);
347 }
348 
349 static void test_init_timer_irq(struct kvm_vm *vm)
350 {
351 	/* Timer initid should be same for all the vCPUs, so query only vCPU-0 */
352 	int vcpu0_fd = vcpu_get_fd(vm, 0);
353 
354 	kvm_device_access(vcpu0_fd, KVM_ARM_VCPU_TIMER_CTRL,
355 			KVM_ARM_VCPU_TIMER_IRQ_PTIMER, &ptimer_irq, false);
356 	kvm_device_access(vcpu0_fd, KVM_ARM_VCPU_TIMER_CTRL,
357 			KVM_ARM_VCPU_TIMER_IRQ_VTIMER, &vtimer_irq, false);
358 
359 	sync_global_to_guest(vm, ptimer_irq);
360 	sync_global_to_guest(vm, vtimer_irq);
361 
362 	pr_debug("ptimer_irq: %d; vtimer_irq: %d\n", ptimer_irq, vtimer_irq);
363 }
364 
365 static struct kvm_vm *test_vm_create(void)
366 {
367 	struct kvm_vm *vm;
368 	unsigned int i;
369 	int nr_vcpus = test_args.nr_vcpus;
370 
371 	vm = vm_create_default_with_vcpus(nr_vcpus, 0, 0, guest_code, NULL);
372 
373 	vm_init_descriptor_tables(vm);
374 	vm_install_exception_handler(vm, VECTOR_IRQ_CURRENT, guest_irq_handler);
375 
376 	for (i = 0; i < nr_vcpus; i++) {
377 		vcpu_init_descriptor_tables(vm, i);
378 
379 		test_vcpu[i].vcpuid = i;
380 		test_vcpu[i].vm = vm;
381 	}
382 
383 	ucall_init(vm, NULL);
384 	test_init_timer_irq(vm);
385 	vgic_v3_setup(vm, nr_vcpus, 64, GICD_BASE_GPA, GICR_BASE_GPA);
386 
387 	/* Make all the test's cmdline args visible to the guest */
388 	sync_global_to_guest(vm, test_args);
389 
390 	return vm;
391 }
392 
393 static void test_print_help(char *name)
394 {
395 	pr_info("Usage: %s [-h] [-n nr_vcpus] [-i iterations] [-p timer_period_ms]\n",
396 		name);
397 	pr_info("\t-n: Number of vCPUs to configure (default: %u; max: %u)\n",
398 		NR_VCPUS_DEF, KVM_MAX_VCPUS);
399 	pr_info("\t-i: Number of iterations per stage (default: %u)\n",
400 		NR_TEST_ITERS_DEF);
401 	pr_info("\t-p: Periodicity (in ms) of the guest timer (default: %u)\n",
402 		TIMER_TEST_PERIOD_MS_DEF);
403 	pr_info("\t-m: Frequency (in ms) of vCPUs to migrate to different pCPU. 0 to turn off (default: %u)\n",
404 		TIMER_TEST_MIGRATION_FREQ_MS);
405 	pr_info("\t-h: print this help screen\n");
406 }
407 
408 static bool parse_args(int argc, char *argv[])
409 {
410 	int opt;
411 
412 	while ((opt = getopt(argc, argv, "hn:i:p:m:")) != -1) {
413 		switch (opt) {
414 		case 'n':
415 			test_args.nr_vcpus = atoi(optarg);
416 			if (test_args.nr_vcpus <= 0) {
417 				pr_info("Positive value needed for -n\n");
418 				goto err;
419 			} else if (test_args.nr_vcpus > KVM_MAX_VCPUS) {
420 				pr_info("Max allowed vCPUs: %u\n",
421 					KVM_MAX_VCPUS);
422 				goto err;
423 			}
424 			break;
425 		case 'i':
426 			test_args.nr_iter = atoi(optarg);
427 			if (test_args.nr_iter <= 0) {
428 				pr_info("Positive value needed for -i\n");
429 				goto err;
430 			}
431 			break;
432 		case 'p':
433 			test_args.timer_period_ms = atoi(optarg);
434 			if (test_args.timer_period_ms <= 0) {
435 				pr_info("Positive value needed for -p\n");
436 				goto err;
437 			}
438 			break;
439 		case 'm':
440 			test_args.migration_freq_ms = atoi(optarg);
441 			if (test_args.migration_freq_ms < 0) {
442 				pr_info("0 or positive value needed for -m\n");
443 				goto err;
444 			}
445 			break;
446 		case 'h':
447 		default:
448 			goto err;
449 		}
450 	}
451 
452 	return true;
453 
454 err:
455 	test_print_help(argv[0]);
456 	return false;
457 }
458 
459 int main(int argc, char *argv[])
460 {
461 	struct kvm_vm *vm;
462 
463 	/* Tell stdout not to buffer its content */
464 	setbuf(stdout, NULL);
465 
466 	if (!parse_args(argc, argv))
467 		exit(KSFT_SKIP);
468 
469 	if (test_args.migration_freq_ms && get_nprocs() < 2) {
470 		print_skip("At least two physical CPUs needed for vCPU migration");
471 		exit(KSFT_SKIP);
472 	}
473 
474 	vm = test_vm_create();
475 	test_run(vm);
476 	kvm_vm_free(vm);
477 
478 	return 0;
479 }
480