1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * arch_timer.c - Tests the arch timer IRQ functionality
4 *
5 * The guest's main thread configures the timer interrupt and waits
6 * for it to fire, with a timeout equal to the timer period.
7 * It asserts that the timeout doesn't exceed the timer period plus
8 * a user configurable error margin(default to 100us)
9 *
10 * On the other hand, upon receipt of an interrupt, the guest's interrupt
11 * handler validates the interrupt by checking if the architectural state
12 * is in compliance with the specifications.
13 *
14 * The test provides command-line options to configure the timer's
15 * period (-p), number of vCPUs (-n), iterations per stage (-i) and timer
16 * interrupt arrival error margin (-e). To stress-test the timer stack
17 * even more, an option to migrate the vCPUs across pCPUs (-m), at a
18 * particular rate, is also provided.
19 *
20 * Copyright (c) 2021, Google LLC.
21 */
22 #include <stdlib.h>
23 #include <pthread.h>
24 #include <linux/sizes.h>
25 #include <linux/bitmap.h>
26 #include <sys/sysinfo.h>
27
28 #include "timer_test.h"
29 #include "ucall_common.h"
30
31 struct test_args test_args = {
32 .nr_vcpus = NR_VCPUS_DEF,
33 .nr_iter = NR_TEST_ITERS_DEF,
34 .timer_period_ms = TIMER_TEST_PERIOD_MS_DEF,
35 .migration_freq_ms = TIMER_TEST_MIGRATION_FREQ_MS,
36 .timer_err_margin_us = TIMER_TEST_ERR_MARGIN_US,
37 .reserved = 1,
38 };
39
40 struct kvm_vcpu *vcpus[KVM_MAX_VCPUS];
41 struct test_vcpu_shared_data vcpu_shared_data[KVM_MAX_VCPUS];
42
43 static pthread_t pt_vcpu_run[KVM_MAX_VCPUS];
44 static unsigned long *vcpu_done_map;
45 static pthread_mutex_t vcpu_done_map_lock;
46
test_vcpu_run(void * arg)47 static void *test_vcpu_run(void *arg)
48 {
49 unsigned int vcpu_idx = (unsigned long)arg;
50 struct ucall uc;
51 struct kvm_vcpu *vcpu = vcpus[vcpu_idx];
52 struct kvm_vm *vm = vcpu->vm;
53 struct test_vcpu_shared_data *shared_data = &vcpu_shared_data[vcpu_idx];
54
55 vcpu_run(vcpu);
56
57 /* Currently, any exit from guest is an indication of completion */
58 pthread_mutex_lock(&vcpu_done_map_lock);
59 __set_bit(vcpu_idx, vcpu_done_map);
60 pthread_mutex_unlock(&vcpu_done_map_lock);
61
62 switch (get_ucall(vcpu, &uc)) {
63 case UCALL_SYNC:
64 case UCALL_DONE:
65 break;
66 case UCALL_ABORT:
67 sync_global_from_guest(vm, *shared_data);
68 fprintf(stderr, "Guest assert failed, vcpu %u; stage; %u; iter: %u\n",
69 vcpu_idx, shared_data->guest_stage, shared_data->nr_iter);
70 REPORT_GUEST_ASSERT(uc);
71 break;
72 default:
73 TEST_FAIL("Unexpected guest exit");
74 }
75
76 pr_info("PASS(vCPU-%d).\n", vcpu_idx);
77
78 return NULL;
79 }
80
test_get_pcpu(void)81 static uint32_t test_get_pcpu(void)
82 {
83 uint32_t pcpu;
84 unsigned int nproc_conf;
85 cpu_set_t online_cpuset;
86
87 nproc_conf = get_nprocs_conf();
88 sched_getaffinity(0, sizeof(cpu_set_t), &online_cpuset);
89
90 /* Randomly find an available pCPU to place a vCPU on */
91 do {
92 pcpu = rand() % nproc_conf;
93 } while (!CPU_ISSET(pcpu, &online_cpuset));
94
95 return pcpu;
96 }
97
test_migrate_vcpu(unsigned int vcpu_idx)98 static int test_migrate_vcpu(unsigned int vcpu_idx)
99 {
100 int ret;
101 cpu_set_t cpuset;
102 uint32_t new_pcpu = test_get_pcpu();
103
104 CPU_ZERO(&cpuset);
105 CPU_SET(new_pcpu, &cpuset);
106
107 pr_debug("Migrating vCPU: %u to pCPU: %u\n", vcpu_idx, new_pcpu);
108
109 ret = pthread_setaffinity_np(pt_vcpu_run[vcpu_idx],
110 sizeof(cpuset), &cpuset);
111
112 /* Allow the error where the vCPU thread is already finished */
113 TEST_ASSERT(ret == 0 || ret == ESRCH,
114 "Failed to migrate the vCPU:%u to pCPU: %u; ret: %d",
115 vcpu_idx, new_pcpu, ret);
116
117 return ret;
118 }
119
test_vcpu_migration(void * arg)120 static void *test_vcpu_migration(void *arg)
121 {
122 unsigned int i, n_done;
123 bool vcpu_done;
124
125 do {
126 usleep(msecs_to_usecs(test_args.migration_freq_ms));
127
128 for (n_done = 0, i = 0; i < test_args.nr_vcpus; i++) {
129 pthread_mutex_lock(&vcpu_done_map_lock);
130 vcpu_done = test_bit(i, vcpu_done_map);
131 pthread_mutex_unlock(&vcpu_done_map_lock);
132
133 if (vcpu_done) {
134 n_done++;
135 continue;
136 }
137
138 test_migrate_vcpu(i);
139 }
140 } while (test_args.nr_vcpus != n_done);
141
142 return NULL;
143 }
144
test_run(struct kvm_vm * vm)145 static void test_run(struct kvm_vm *vm)
146 {
147 pthread_t pt_vcpu_migration;
148 unsigned int i;
149 int ret;
150
151 pthread_mutex_init(&vcpu_done_map_lock, NULL);
152 vcpu_done_map = bitmap_zalloc(test_args.nr_vcpus);
153 TEST_ASSERT(vcpu_done_map, "Failed to allocate vcpu done bitmap");
154
155 for (i = 0; i < (unsigned long)test_args.nr_vcpus; i++) {
156 ret = pthread_create(&pt_vcpu_run[i], NULL, test_vcpu_run,
157 (void *)(unsigned long)i);
158 TEST_ASSERT(!ret, "Failed to create vCPU-%d pthread", i);
159 }
160
161 /* Spawn a thread to control the vCPU migrations */
162 if (test_args.migration_freq_ms) {
163 srand(time(NULL));
164
165 ret = pthread_create(&pt_vcpu_migration, NULL,
166 test_vcpu_migration, NULL);
167 TEST_ASSERT(!ret, "Failed to create the migration pthread");
168 }
169
170
171 for (i = 0; i < test_args.nr_vcpus; i++)
172 pthread_join(pt_vcpu_run[i], NULL);
173
174 if (test_args.migration_freq_ms)
175 pthread_join(pt_vcpu_migration, NULL);
176
177 bitmap_free(vcpu_done_map);
178 }
179
test_print_help(char * name)180 static void test_print_help(char *name)
181 {
182 pr_info("Usage: %s [-h] [-n nr_vcpus] [-i iterations] [-p timer_period_ms]\n"
183 "\t\t [-m migration_freq_ms] [-o counter_offset]\n"
184 "\t\t [-e timer_err_margin_us]\n", name);
185 pr_info("\t-n: Number of vCPUs to configure (default: %u; max: %u)\n",
186 NR_VCPUS_DEF, KVM_MAX_VCPUS);
187 pr_info("\t-i: Number of iterations per stage (default: %u)\n",
188 NR_TEST_ITERS_DEF);
189 pr_info("\t-p: Periodicity (in ms) of the guest timer (default: %u)\n",
190 TIMER_TEST_PERIOD_MS_DEF);
191 pr_info("\t-m: Frequency (in ms) of vCPUs to migrate to different pCPU. 0 to turn off (default: %u)\n",
192 TIMER_TEST_MIGRATION_FREQ_MS);
193 pr_info("\t-o: Counter offset (in counter cycles, default: 0) [aarch64-only]\n");
194 pr_info("\t-e: Interrupt arrival error margin (in us) of the guest timer (default: %u)\n",
195 TIMER_TEST_ERR_MARGIN_US);
196 pr_info("\t-h: print this help screen\n");
197 }
198
parse_args(int argc,char * argv[])199 static bool parse_args(int argc, char *argv[])
200 {
201 int opt;
202
203 while ((opt = getopt(argc, argv, "hn:i:p:m:o:e:")) != -1) {
204 switch (opt) {
205 case 'n':
206 test_args.nr_vcpus = atoi_positive("Number of vCPUs", optarg);
207 if (test_args.nr_vcpus > KVM_MAX_VCPUS) {
208 pr_info("Max allowed vCPUs: %u\n",
209 KVM_MAX_VCPUS);
210 goto err;
211 }
212 break;
213 case 'i':
214 test_args.nr_iter = atoi_positive("Number of iterations", optarg);
215 break;
216 case 'p':
217 test_args.timer_period_ms = atoi_positive("Periodicity", optarg);
218 break;
219 case 'm':
220 test_args.migration_freq_ms = atoi_non_negative("Frequency", optarg);
221 break;
222 case 'e':
223 test_args.timer_err_margin_us = atoi_non_negative("Error Margin", optarg);
224 break;
225 case 'o':
226 test_args.counter_offset = strtol(optarg, NULL, 0);
227 test_args.reserved = 0;
228 break;
229 case 'h':
230 default:
231 goto err;
232 }
233 }
234
235 return true;
236
237 err:
238 test_print_help(argv[0]);
239 return false;
240 }
241
main(int argc,char * argv[])242 int main(int argc, char *argv[])
243 {
244 struct kvm_vm *vm;
245
246 if (!parse_args(argc, argv))
247 exit(KSFT_SKIP);
248
249 __TEST_REQUIRE(!test_args.migration_freq_ms || get_nprocs() >= 2,
250 "At least two physical CPUs needed for vCPU migration");
251
252 vm = test_vm_create();
253 test_run(vm);
254 test_vm_cleanup(vm);
255
256 return 0;
257 }
258