1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * KVM demand paging test
4 * Adapted from dirty_log_test.c
5 *
6 * Copyright (C) 2018, Red Hat, Inc.
7 * Copyright (C) 2019, Google, Inc.
8 */
9
10 #define _GNU_SOURCE /* for program_invocation_name */
11
12 #include <stdio.h>
13 #include <stdlib.h>
14 #include <sys/syscall.h>
15 #include <unistd.h>
16 #include <asm/unistd.h>
17 #include <time.h>
18 #include <poll.h>
19 #include <pthread.h>
20 #include <linux/bitmap.h>
21 #include <linux/bitops.h>
22 #include <linux/userfaultfd.h>
23
24 #include "perf_test_util.h"
25 #include "processor.h"
26 #include "test_util.h"
27
28 #ifdef __NR_userfaultfd
29
30 #ifdef PRINT_PER_PAGE_UPDATES
31 #define PER_PAGE_DEBUG(...) printf(__VA_ARGS__)
32 #else
33 #define PER_PAGE_DEBUG(...) _no_printf(__VA_ARGS__)
34 #endif
35
36 #ifdef PRINT_PER_VCPU_UPDATES
37 #define PER_VCPU_DEBUG(...) printf(__VA_ARGS__)
38 #else
39 #define PER_VCPU_DEBUG(...) _no_printf(__VA_ARGS__)
40 #endif
41
42 static char *guest_data_prototype;
43
vcpu_worker(void * data)44 static void *vcpu_worker(void *data)
45 {
46 int ret;
47 struct vcpu_args *vcpu_args = (struct vcpu_args *)data;
48 int vcpu_id = vcpu_args->vcpu_id;
49 struct kvm_vm *vm = perf_test_args.vm;
50 struct kvm_run *run;
51 struct timespec start;
52 struct timespec ts_diff;
53
54 vcpu_args_set(vm, vcpu_id, 1, vcpu_id);
55 run = vcpu_state(vm, vcpu_id);
56
57 clock_gettime(CLOCK_MONOTONIC, &start);
58
59 /* Let the guest access its memory */
60 ret = _vcpu_run(vm, vcpu_id);
61 TEST_ASSERT(ret == 0, "vcpu_run failed: %d\n", ret);
62 if (get_ucall(vm, vcpu_id, NULL) != UCALL_SYNC) {
63 TEST_ASSERT(false,
64 "Invalid guest sync status: exit_reason=%s\n",
65 exit_reason_str(run->exit_reason));
66 }
67
68 ts_diff = timespec_diff_now(start);
69 PER_VCPU_DEBUG("vCPU %d execution time: %ld.%.9lds\n", vcpu_id,
70 ts_diff.tv_sec, ts_diff.tv_nsec);
71
72 return NULL;
73 }
74
handle_uffd_page_request(int uffd,uint64_t addr)75 static int handle_uffd_page_request(int uffd, uint64_t addr)
76 {
77 pid_t tid;
78 struct timespec start;
79 struct timespec ts_diff;
80 struct uffdio_copy copy;
81 int r;
82
83 tid = syscall(__NR_gettid);
84
85 copy.src = (uint64_t)guest_data_prototype;
86 copy.dst = addr;
87 copy.len = perf_test_args.host_page_size;
88 copy.mode = 0;
89
90 clock_gettime(CLOCK_MONOTONIC, &start);
91
92 r = ioctl(uffd, UFFDIO_COPY, ©);
93 if (r == -1) {
94 pr_info("Failed Paged in 0x%lx from thread %d with errno: %d\n",
95 addr, tid, errno);
96 return r;
97 }
98
99 ts_diff = timespec_diff_now(start);
100
101 PER_PAGE_DEBUG("UFFDIO_COPY %d \t%ld ns\n", tid,
102 timespec_to_ns(ts_diff));
103 PER_PAGE_DEBUG("Paged in %ld bytes at 0x%lx from thread %d\n",
104 perf_test_args.host_page_size, addr, tid);
105
106 return 0;
107 }
108
109 bool quit_uffd_thread;
110
111 struct uffd_handler_args {
112 int uffd;
113 int pipefd;
114 useconds_t delay;
115 };
116
uffd_handler_thread_fn(void * arg)117 static void *uffd_handler_thread_fn(void *arg)
118 {
119 struct uffd_handler_args *uffd_args = (struct uffd_handler_args *)arg;
120 int uffd = uffd_args->uffd;
121 int pipefd = uffd_args->pipefd;
122 useconds_t delay = uffd_args->delay;
123 int64_t pages = 0;
124 struct timespec start;
125 struct timespec ts_diff;
126
127 clock_gettime(CLOCK_MONOTONIC, &start);
128 while (!quit_uffd_thread) {
129 struct uffd_msg msg;
130 struct pollfd pollfd[2];
131 char tmp_chr;
132 int r;
133 uint64_t addr;
134
135 pollfd[0].fd = uffd;
136 pollfd[0].events = POLLIN;
137 pollfd[1].fd = pipefd;
138 pollfd[1].events = POLLIN;
139
140 r = poll(pollfd, 2, -1);
141 switch (r) {
142 case -1:
143 pr_info("poll err");
144 continue;
145 case 0:
146 continue;
147 case 1:
148 break;
149 default:
150 pr_info("Polling uffd returned %d", r);
151 return NULL;
152 }
153
154 if (pollfd[0].revents & POLLERR) {
155 pr_info("uffd revents has POLLERR");
156 return NULL;
157 }
158
159 if (pollfd[1].revents & POLLIN) {
160 r = read(pollfd[1].fd, &tmp_chr, 1);
161 TEST_ASSERT(r == 1,
162 "Error reading pipefd in UFFD thread\n");
163 return NULL;
164 }
165
166 if (!pollfd[0].revents & POLLIN)
167 continue;
168
169 r = read(uffd, &msg, sizeof(msg));
170 if (r == -1) {
171 if (errno == EAGAIN)
172 continue;
173 pr_info("Read of uffd gor errno %d", errno);
174 return NULL;
175 }
176
177 if (r != sizeof(msg)) {
178 pr_info("Read on uffd returned unexpected size: %d bytes", r);
179 return NULL;
180 }
181
182 if (!(msg.event & UFFD_EVENT_PAGEFAULT))
183 continue;
184
185 if (delay)
186 usleep(delay);
187 addr = msg.arg.pagefault.address;
188 r = handle_uffd_page_request(uffd, addr);
189 if (r < 0)
190 return NULL;
191 pages++;
192 }
193
194 ts_diff = timespec_diff_now(start);
195 PER_VCPU_DEBUG("userfaulted %ld pages over %ld.%.9lds. (%f/sec)\n",
196 pages, ts_diff.tv_sec, ts_diff.tv_nsec,
197 pages / ((double)ts_diff.tv_sec + (double)ts_diff.tv_nsec / 100000000.0));
198
199 return NULL;
200 }
201
setup_demand_paging(struct kvm_vm * vm,pthread_t * uffd_handler_thread,int pipefd,useconds_t uffd_delay,struct uffd_handler_args * uffd_args,void * hva,uint64_t len)202 static int setup_demand_paging(struct kvm_vm *vm,
203 pthread_t *uffd_handler_thread, int pipefd,
204 useconds_t uffd_delay,
205 struct uffd_handler_args *uffd_args,
206 void *hva, uint64_t len)
207 {
208 int uffd;
209 struct uffdio_api uffdio_api;
210 struct uffdio_register uffdio_register;
211
212 uffd = syscall(__NR_userfaultfd, O_CLOEXEC | O_NONBLOCK);
213 if (uffd == -1) {
214 pr_info("uffd creation failed\n");
215 return -1;
216 }
217
218 uffdio_api.api = UFFD_API;
219 uffdio_api.features = 0;
220 if (ioctl(uffd, UFFDIO_API, &uffdio_api) == -1) {
221 pr_info("ioctl uffdio_api failed\n");
222 return -1;
223 }
224
225 uffdio_register.range.start = (uint64_t)hva;
226 uffdio_register.range.len = len;
227 uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
228 if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register) == -1) {
229 pr_info("ioctl uffdio_register failed\n");
230 return -1;
231 }
232
233 if ((uffdio_register.ioctls & UFFD_API_RANGE_IOCTLS) !=
234 UFFD_API_RANGE_IOCTLS) {
235 pr_info("unexpected userfaultfd ioctl set\n");
236 return -1;
237 }
238
239 uffd_args->uffd = uffd;
240 uffd_args->pipefd = pipefd;
241 uffd_args->delay = uffd_delay;
242 pthread_create(uffd_handler_thread, NULL, uffd_handler_thread_fn,
243 uffd_args);
244
245 PER_VCPU_DEBUG("Created uffd thread for HVA range [%p, %p)\n",
246 hva, hva + len);
247
248 return 0;
249 }
250
run_test(enum vm_guest_mode mode,bool use_uffd,useconds_t uffd_delay)251 static void run_test(enum vm_guest_mode mode, bool use_uffd,
252 useconds_t uffd_delay)
253 {
254 pthread_t *vcpu_threads;
255 pthread_t *uffd_handler_threads = NULL;
256 struct uffd_handler_args *uffd_args = NULL;
257 struct timespec start;
258 struct timespec ts_diff;
259 int *pipefds = NULL;
260 struct kvm_vm *vm;
261 int vcpu_id;
262 int r;
263
264 vm = create_vm(mode, nr_vcpus, guest_percpu_mem_size);
265
266 perf_test_args.wr_fract = 1;
267
268 guest_data_prototype = malloc(perf_test_args.host_page_size);
269 TEST_ASSERT(guest_data_prototype,
270 "Failed to allocate buffer for guest data pattern");
271 memset(guest_data_prototype, 0xAB, perf_test_args.host_page_size);
272
273 vcpu_threads = malloc(nr_vcpus * sizeof(*vcpu_threads));
274 TEST_ASSERT(vcpu_threads, "Memory allocation failed");
275
276 add_vcpus(vm, nr_vcpus, guest_percpu_mem_size);
277
278 if (use_uffd) {
279 uffd_handler_threads =
280 malloc(nr_vcpus * sizeof(*uffd_handler_threads));
281 TEST_ASSERT(uffd_handler_threads, "Memory allocation failed");
282
283 uffd_args = malloc(nr_vcpus * sizeof(*uffd_args));
284 TEST_ASSERT(uffd_args, "Memory allocation failed");
285
286 pipefds = malloc(sizeof(int) * nr_vcpus * 2);
287 TEST_ASSERT(pipefds, "Unable to allocate memory for pipefd");
288
289 for (vcpu_id = 0; vcpu_id < nr_vcpus; vcpu_id++) {
290 vm_paddr_t vcpu_gpa;
291 void *vcpu_hva;
292
293 vcpu_gpa = guest_test_phys_mem + (vcpu_id * guest_percpu_mem_size);
294 PER_VCPU_DEBUG("Added VCPU %d with test mem gpa [%lx, %lx)\n",
295 vcpu_id, vcpu_gpa, vcpu_gpa + guest_percpu_mem_size);
296
297 /* Cache the HVA pointer of the region */
298 vcpu_hva = addr_gpa2hva(vm, vcpu_gpa);
299
300 /*
301 * Set up user fault fd to handle demand paging
302 * requests.
303 */
304 r = pipe2(&pipefds[vcpu_id * 2],
305 O_CLOEXEC | O_NONBLOCK);
306 TEST_ASSERT(!r, "Failed to set up pipefd");
307
308 r = setup_demand_paging(vm,
309 &uffd_handler_threads[vcpu_id],
310 pipefds[vcpu_id * 2],
311 uffd_delay, &uffd_args[vcpu_id],
312 vcpu_hva, guest_percpu_mem_size);
313 if (r < 0)
314 exit(-r);
315 }
316 }
317
318 /* Export the shared variables to the guest */
319 sync_global_to_guest(vm, perf_test_args);
320
321 pr_info("Finished creating vCPUs and starting uffd threads\n");
322
323 clock_gettime(CLOCK_MONOTONIC, &start);
324
325 for (vcpu_id = 0; vcpu_id < nr_vcpus; vcpu_id++) {
326 pthread_create(&vcpu_threads[vcpu_id], NULL, vcpu_worker,
327 &perf_test_args.vcpu_args[vcpu_id]);
328 }
329
330 pr_info("Started all vCPUs\n");
331
332 /* Wait for the vcpu threads to quit */
333 for (vcpu_id = 0; vcpu_id < nr_vcpus; vcpu_id++) {
334 pthread_join(vcpu_threads[vcpu_id], NULL);
335 PER_VCPU_DEBUG("Joined thread for vCPU %d\n", vcpu_id);
336 }
337
338 ts_diff = timespec_diff_now(start);
339
340 pr_info("All vCPU threads joined\n");
341
342 if (use_uffd) {
343 char c;
344
345 /* Tell the user fault fd handler threads to quit */
346 for (vcpu_id = 0; vcpu_id < nr_vcpus; vcpu_id++) {
347 r = write(pipefds[vcpu_id * 2 + 1], &c, 1);
348 TEST_ASSERT(r == 1, "Unable to write to pipefd");
349
350 pthread_join(uffd_handler_threads[vcpu_id], NULL);
351 }
352 }
353
354 pr_info("Total guest execution time: %ld.%.9lds\n",
355 ts_diff.tv_sec, ts_diff.tv_nsec);
356 pr_info("Overall demand paging rate: %f pgs/sec\n",
357 perf_test_args.vcpu_args[0].pages * nr_vcpus /
358 ((double)ts_diff.tv_sec + (double)ts_diff.tv_nsec / 100000000.0));
359
360 ucall_uninit(vm);
361 kvm_vm_free(vm);
362
363 free(guest_data_prototype);
364 free(vcpu_threads);
365 if (use_uffd) {
366 free(uffd_handler_threads);
367 free(uffd_args);
368 free(pipefds);
369 }
370 }
371
372 struct guest_mode {
373 bool supported;
374 bool enabled;
375 };
376 static struct guest_mode guest_modes[NUM_VM_MODES];
377
378 #define guest_mode_init(mode, supported, enabled) ({ \
379 guest_modes[mode] = (struct guest_mode){ supported, enabled }; \
380 })
381
help(char * name)382 static void help(char *name)
383 {
384 int i;
385
386 puts("");
387 printf("usage: %s [-h] [-m mode] [-u] [-d uffd_delay_usec]\n"
388 " [-b memory] [-v vcpus]\n", name);
389 printf(" -m: specify the guest mode ID to test\n"
390 " (default: test all supported modes)\n"
391 " This option may be used multiple times.\n"
392 " Guest mode IDs:\n");
393 for (i = 0; i < NUM_VM_MODES; ++i) {
394 printf(" %d: %s%s\n", i, vm_guest_mode_string(i),
395 guest_modes[i].supported ? " (supported)" : "");
396 }
397 printf(" -u: use User Fault FD to handle vCPU page\n"
398 " faults.\n");
399 printf(" -d: add a delay in usec to the User Fault\n"
400 " FD handler to simulate demand paging\n"
401 " overheads. Ignored without -u.\n");
402 printf(" -b: specify the size of the memory region which should be\n"
403 " demand paged by each vCPU. e.g. 10M or 3G.\n"
404 " Default: 1G\n");
405 printf(" -v: specify the number of vCPUs to run.\n");
406 puts("");
407 exit(0);
408 }
409
main(int argc,char * argv[])410 int main(int argc, char *argv[])
411 {
412 int max_vcpus = kvm_check_cap(KVM_CAP_MAX_VCPUS);
413 bool mode_selected = false;
414 unsigned int mode;
415 int opt, i;
416 bool use_uffd = false;
417 useconds_t uffd_delay = 0;
418
419 #ifdef __x86_64__
420 guest_mode_init(VM_MODE_PXXV48_4K, true, true);
421 #endif
422 #ifdef __aarch64__
423 guest_mode_init(VM_MODE_P40V48_4K, true, true);
424 guest_mode_init(VM_MODE_P40V48_64K, true, true);
425 {
426 unsigned int limit = kvm_check_cap(KVM_CAP_ARM_VM_IPA_SIZE);
427
428 if (limit >= 52)
429 guest_mode_init(VM_MODE_P52V48_64K, true, true);
430 if (limit >= 48) {
431 guest_mode_init(VM_MODE_P48V48_4K, true, true);
432 guest_mode_init(VM_MODE_P48V48_64K, true, true);
433 }
434 }
435 #endif
436 #ifdef __s390x__
437 guest_mode_init(VM_MODE_P40V48_4K, true, true);
438 #endif
439
440 while ((opt = getopt(argc, argv, "hm:ud:b:v:")) != -1) {
441 switch (opt) {
442 case 'm':
443 if (!mode_selected) {
444 for (i = 0; i < NUM_VM_MODES; ++i)
445 guest_modes[i].enabled = false;
446 mode_selected = true;
447 }
448 mode = strtoul(optarg, NULL, 10);
449 TEST_ASSERT(mode < NUM_VM_MODES,
450 "Guest mode ID %d too big", mode);
451 guest_modes[mode].enabled = true;
452 break;
453 case 'u':
454 use_uffd = true;
455 break;
456 case 'd':
457 uffd_delay = strtoul(optarg, NULL, 0);
458 TEST_ASSERT(uffd_delay >= 0,
459 "A negative UFFD delay is not supported.");
460 break;
461 case 'b':
462 guest_percpu_mem_size = parse_size(optarg);
463 break;
464 case 'v':
465 nr_vcpus = atoi(optarg);
466 TEST_ASSERT(nr_vcpus > 0 && nr_vcpus <= max_vcpus,
467 "Invalid number of vcpus, must be between 1 and %d", max_vcpus);
468 break;
469 case 'h':
470 default:
471 help(argv[0]);
472 break;
473 }
474 }
475
476 for (i = 0; i < NUM_VM_MODES; ++i) {
477 if (!guest_modes[i].enabled)
478 continue;
479 TEST_ASSERT(guest_modes[i].supported,
480 "Guest mode ID %d (%s) not supported.",
481 i, vm_guest_mode_string(i));
482 run_test(i, use_uffd, uffd_delay);
483 }
484
485 return 0;
486 }
487
488 #else /* __NR_userfaultfd */
489
490 #warning "missing __NR_userfaultfd definition"
491
main(void)492 int main(void)
493 {
494 print_skip("__NR_userfaultfd must be present for userfaultfd test");
495 return KSFT_SKIP;
496 }
497
498 #endif /* __NR_userfaultfd */
499