1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * KVM page table test
4 *
5 * Copyright (C) 2021, Huawei, Inc.
6 *
7 * Make sure that THP has been enabled or enough HUGETLB pages with specific
8 * page size have been pre-allocated on your system, if you are planning to
9 * use hugepages to back the guest memory for testing.
10 */
11
12 #define _GNU_SOURCE /* for program_invocation_name */
13
14 #include <stdio.h>
15 #include <stdlib.h>
16 #include <time.h>
17 #include <pthread.h>
18 #include <semaphore.h>
19
20 #include "test_util.h"
21 #include "kvm_util.h"
22 #include "processor.h"
23 #include "guest_modes.h"
24
25 #define TEST_MEM_SLOT_INDEX 1
26
27 /* Default size(1GB) of the memory for testing */
28 #define DEFAULT_TEST_MEM_SIZE (1 << 30)
29
30 /* Default guest test virtual memory offset */
31 #define DEFAULT_GUEST_TEST_MEM 0xc0000000
32
33 /* Different guest memory accessing stages */
34 enum test_stage {
35 KVM_BEFORE_MAPPINGS,
36 KVM_CREATE_MAPPINGS,
37 KVM_UPDATE_MAPPINGS,
38 KVM_ADJUST_MAPPINGS,
39 NUM_TEST_STAGES,
40 };
41
42 static const char * const test_stage_string[] = {
43 "KVM_BEFORE_MAPPINGS",
44 "KVM_CREATE_MAPPINGS",
45 "KVM_UPDATE_MAPPINGS",
46 "KVM_ADJUST_MAPPINGS",
47 };
48
49 struct vcpu_args {
50 int vcpu_id;
51 bool vcpu_write;
52 };
53
54 struct test_args {
55 struct kvm_vm *vm;
56 uint64_t guest_test_virt_mem;
57 uint64_t host_page_size;
58 uint64_t host_num_pages;
59 uint64_t large_page_size;
60 uint64_t large_num_pages;
61 uint64_t host_pages_per_lpage;
62 enum vm_mem_backing_src_type src_type;
63 struct vcpu_args vcpu_args[KVM_MAX_VCPUS];
64 };
65
66 /*
67 * Guest variables. Use addr_gva2hva() if these variables need
68 * to be changed in host.
69 */
70 static enum test_stage guest_test_stage;
71
72 /* Host variables */
73 static uint32_t nr_vcpus = 1;
74 static struct test_args test_args;
75 static enum test_stage *current_stage;
76 static bool host_quit;
77
78 /* Whether the test stage is updated, or completed */
79 static sem_t test_stage_updated;
80 static sem_t test_stage_completed;
81
82 /*
83 * Guest physical memory offset of the testing memory slot.
84 * This will be set to the topmost valid physical address minus
85 * the test memory size.
86 */
87 static uint64_t guest_test_phys_mem;
88
89 /*
90 * Guest virtual memory offset of the testing memory slot.
91 * Must not conflict with identity mapped test code.
92 */
93 static uint64_t guest_test_virt_mem = DEFAULT_GUEST_TEST_MEM;
94
guest_code(int vcpu_id)95 static void guest_code(int vcpu_id)
96 {
97 struct test_args *p = &test_args;
98 struct vcpu_args *vcpu_args = &p->vcpu_args[vcpu_id];
99 enum test_stage *current_stage = &guest_test_stage;
100 uint64_t addr;
101 int i, j;
102
103 /* Make sure vCPU args data structure is not corrupt */
104 GUEST_ASSERT(vcpu_args->vcpu_id == vcpu_id);
105
106 while (true) {
107 addr = p->guest_test_virt_mem;
108
109 switch (READ_ONCE(*current_stage)) {
110 /*
111 * All vCPU threads will be started in this stage,
112 * where guest code of each vCPU will do nothing.
113 */
114 case KVM_BEFORE_MAPPINGS:
115 break;
116
117 /*
118 * Before dirty logging, vCPUs concurrently access the first
119 * 8 bytes of each page (host page/large page) within the same
120 * memory region with different accessing types (read/write).
121 * Then KVM will create normal page mappings or huge block
122 * mappings for them.
123 */
124 case KVM_CREATE_MAPPINGS:
125 for (i = 0; i < p->large_num_pages; i++) {
126 if (vcpu_args->vcpu_write)
127 *(uint64_t *)addr = 0x0123456789ABCDEF;
128 else
129 READ_ONCE(*(uint64_t *)addr);
130
131 addr += p->large_page_size;
132 }
133 break;
134
135 /*
136 * During dirty logging, KVM will only update attributes of the
137 * normal page mappings from RO to RW if memory backing src type
138 * is anonymous. In other cases, KVM will split the huge block
139 * mappings into normal page mappings if memory backing src type
140 * is THP or HUGETLB.
141 */
142 case KVM_UPDATE_MAPPINGS:
143 if (p->src_type == VM_MEM_SRC_ANONYMOUS) {
144 for (i = 0; i < p->host_num_pages; i++) {
145 *(uint64_t *)addr = 0x0123456789ABCDEF;
146 addr += p->host_page_size;
147 }
148 break;
149 }
150
151 for (i = 0; i < p->large_num_pages; i++) {
152 /*
153 * Write to the first host page in each large
154 * page region, and triger break of large pages.
155 */
156 *(uint64_t *)addr = 0x0123456789ABCDEF;
157
158 /*
159 * Access the middle host pages in each large
160 * page region. Since dirty logging is enabled,
161 * this will create new mappings at the smallest
162 * granularity.
163 */
164 addr += p->large_page_size / 2;
165 for (j = 0; j < p->host_pages_per_lpage / 2; j++) {
166 READ_ONCE(*(uint64_t *)addr);
167 addr += p->host_page_size;
168 }
169 }
170 break;
171
172 /*
173 * After dirty logging is stopped, vCPUs concurrently read
174 * from every single host page. Then KVM will coalesce the
175 * split page mappings back to block mappings. And a TLB
176 * conflict abort could occur here if TLB entries of the
177 * page mappings are not fully invalidated.
178 */
179 case KVM_ADJUST_MAPPINGS:
180 for (i = 0; i < p->host_num_pages; i++) {
181 READ_ONCE(*(uint64_t *)addr);
182 addr += p->host_page_size;
183 }
184 break;
185
186 default:
187 GUEST_ASSERT(0);
188 }
189
190 GUEST_SYNC(1);
191 }
192 }
193
vcpu_worker(void * data)194 static void *vcpu_worker(void *data)
195 {
196 int ret;
197 struct vcpu_args *vcpu_args = data;
198 struct kvm_vm *vm = test_args.vm;
199 int vcpu_id = vcpu_args->vcpu_id;
200 struct kvm_run *run;
201 struct timespec start;
202 struct timespec ts_diff;
203 enum test_stage stage;
204
205 vcpu_args_set(vm, vcpu_id, 1, vcpu_id);
206 run = vcpu_state(vm, vcpu_id);
207
208 while (!READ_ONCE(host_quit)) {
209 ret = sem_wait(&test_stage_updated);
210 TEST_ASSERT(ret == 0, "Error in sem_wait");
211
212 if (READ_ONCE(host_quit))
213 return NULL;
214
215 clock_gettime(CLOCK_MONOTONIC_RAW, &start);
216 ret = _vcpu_run(vm, vcpu_id);
217 ts_diff = timespec_elapsed(start);
218
219 TEST_ASSERT(ret == 0, "vcpu_run failed: %d\n", ret);
220 TEST_ASSERT(get_ucall(vm, vcpu_id, NULL) == UCALL_SYNC,
221 "Invalid guest sync status: exit_reason=%s\n",
222 exit_reason_str(run->exit_reason));
223
224 pr_debug("Got sync event from vCPU %d\n", vcpu_id);
225 stage = READ_ONCE(*current_stage);
226
227 /*
228 * Here we can know the execution time of every
229 * single vcpu running in different test stages.
230 */
231 pr_debug("vCPU %d has completed stage %s\n"
232 "execution time is: %ld.%.9lds\n\n",
233 vcpu_id, test_stage_string[stage],
234 ts_diff.tv_sec, ts_diff.tv_nsec);
235
236 ret = sem_post(&test_stage_completed);
237 TEST_ASSERT(ret == 0, "Error in sem_post");
238 }
239
240 return NULL;
241 }
242
243 struct test_params {
244 uint64_t phys_offset;
245 uint64_t test_mem_size;
246 enum vm_mem_backing_src_type src_type;
247 };
248
pre_init_before_test(enum vm_guest_mode mode,void * arg)249 static struct kvm_vm *pre_init_before_test(enum vm_guest_mode mode, void *arg)
250 {
251 int ret;
252 struct test_params *p = arg;
253 struct vcpu_args *vcpu_args;
254 enum vm_mem_backing_src_type src_type = p->src_type;
255 uint64_t large_page_size = get_backing_src_pagesz(src_type);
256 uint64_t guest_page_size = vm_guest_mode_params[mode].page_size;
257 uint64_t host_page_size = getpagesize();
258 uint64_t test_mem_size = p->test_mem_size;
259 uint64_t guest_num_pages;
260 uint64_t alignment;
261 void *host_test_mem;
262 struct kvm_vm *vm;
263 int vcpu_id;
264
265 /* Align up the test memory size */
266 alignment = max(large_page_size, guest_page_size);
267 test_mem_size = (test_mem_size + alignment - 1) & ~(alignment - 1);
268
269 /* Create a VM with enough guest pages */
270 guest_num_pages = test_mem_size / guest_page_size;
271 vm = vm_create_with_vcpus(mode, nr_vcpus, DEFAULT_GUEST_PHY_PAGES,
272 guest_num_pages, 0, guest_code, NULL);
273
274 /* Align down GPA of the testing memslot */
275 if (!p->phys_offset)
276 guest_test_phys_mem = (vm_get_max_gfn(vm) - guest_num_pages) *
277 guest_page_size;
278 else
279 guest_test_phys_mem = p->phys_offset;
280 #ifdef __s390x__
281 alignment = max(0x100000, alignment);
282 #endif
283 guest_test_phys_mem = align_down(guest_test_phys_mem, alignment);
284
285 /* Set up the shared data structure test_args */
286 test_args.vm = vm;
287 test_args.guest_test_virt_mem = guest_test_virt_mem;
288 test_args.host_page_size = host_page_size;
289 test_args.host_num_pages = test_mem_size / host_page_size;
290 test_args.large_page_size = large_page_size;
291 test_args.large_num_pages = test_mem_size / large_page_size;
292 test_args.host_pages_per_lpage = large_page_size / host_page_size;
293 test_args.src_type = src_type;
294
295 for (vcpu_id = 0; vcpu_id < KVM_MAX_VCPUS; vcpu_id++) {
296 vcpu_args = &test_args.vcpu_args[vcpu_id];
297 vcpu_args->vcpu_id = vcpu_id;
298 vcpu_args->vcpu_write = !(vcpu_id % 2);
299 }
300
301 /* Add an extra memory slot with specified backing src type */
302 vm_userspace_mem_region_add(vm, src_type, guest_test_phys_mem,
303 TEST_MEM_SLOT_INDEX, guest_num_pages, 0);
304
305 /* Do mapping(GVA->GPA) for the testing memory slot */
306 virt_map(vm, guest_test_virt_mem, guest_test_phys_mem, guest_num_pages);
307
308 /* Cache the HVA pointer of the region */
309 host_test_mem = addr_gpa2hva(vm, (vm_paddr_t)guest_test_phys_mem);
310
311 /* Export shared structure test_args to guest */
312 ucall_init(vm, NULL);
313 sync_global_to_guest(vm, test_args);
314
315 ret = sem_init(&test_stage_updated, 0, 0);
316 TEST_ASSERT(ret == 0, "Error in sem_init");
317
318 ret = sem_init(&test_stage_completed, 0, 0);
319 TEST_ASSERT(ret == 0, "Error in sem_init");
320
321 current_stage = addr_gva2hva(vm, (vm_vaddr_t)(&guest_test_stage));
322 *current_stage = NUM_TEST_STAGES;
323
324 pr_info("Testing guest mode: %s\n", vm_guest_mode_string(mode));
325 pr_info("Testing memory backing src type: %s\n",
326 vm_mem_backing_src_alias(src_type)->name);
327 pr_info("Testing memory backing src granularity: 0x%lx\n",
328 large_page_size);
329 pr_info("Testing memory size(aligned): 0x%lx\n", test_mem_size);
330 pr_info("Guest physical test memory offset: 0x%lx\n",
331 guest_test_phys_mem);
332 pr_info("Host virtual test memory offset: 0x%lx\n",
333 (uint64_t)host_test_mem);
334 pr_info("Number of testing vCPUs: %d\n", nr_vcpus);
335
336 return vm;
337 }
338
vcpus_complete_new_stage(enum test_stage stage)339 static void vcpus_complete_new_stage(enum test_stage stage)
340 {
341 int ret;
342 int vcpus;
343
344 /* Wake up all the vcpus to run new test stage */
345 for (vcpus = 0; vcpus < nr_vcpus; vcpus++) {
346 ret = sem_post(&test_stage_updated);
347 TEST_ASSERT(ret == 0, "Error in sem_post");
348 }
349 pr_debug("All vcpus have been notified to continue\n");
350
351 /* Wait for all the vcpus to complete new test stage */
352 for (vcpus = 0; vcpus < nr_vcpus; vcpus++) {
353 ret = sem_wait(&test_stage_completed);
354 TEST_ASSERT(ret == 0, "Error in sem_wait");
355
356 pr_debug("%d vcpus have completed stage %s\n",
357 vcpus + 1, test_stage_string[stage]);
358 }
359
360 pr_debug("All vcpus have completed stage %s\n",
361 test_stage_string[stage]);
362 }
363
run_test(enum vm_guest_mode mode,void * arg)364 static void run_test(enum vm_guest_mode mode, void *arg)
365 {
366 int ret;
367 pthread_t *vcpu_threads;
368 struct kvm_vm *vm;
369 int vcpu_id;
370 struct timespec start;
371 struct timespec ts_diff;
372
373 /* Create VM with vCPUs and make some pre-initialization */
374 vm = pre_init_before_test(mode, arg);
375
376 vcpu_threads = malloc(nr_vcpus * sizeof(*vcpu_threads));
377 TEST_ASSERT(vcpu_threads, "Memory allocation failed");
378
379 host_quit = false;
380 *current_stage = KVM_BEFORE_MAPPINGS;
381
382 for (vcpu_id = 0; vcpu_id < nr_vcpus; vcpu_id++) {
383 pthread_create(&vcpu_threads[vcpu_id], NULL, vcpu_worker,
384 &test_args.vcpu_args[vcpu_id]);
385 }
386
387 vcpus_complete_new_stage(*current_stage);
388 pr_info("Started all vCPUs successfully\n");
389
390 /* Test the stage of KVM creating mappings */
391 *current_stage = KVM_CREATE_MAPPINGS;
392
393 clock_gettime(CLOCK_MONOTONIC_RAW, &start);
394 vcpus_complete_new_stage(*current_stage);
395 ts_diff = timespec_elapsed(start);
396
397 pr_info("KVM_CREATE_MAPPINGS: total execution time: %ld.%.9lds\n\n",
398 ts_diff.tv_sec, ts_diff.tv_nsec);
399
400 /* Test the stage of KVM updating mappings */
401 vm_mem_region_set_flags(vm, TEST_MEM_SLOT_INDEX,
402 KVM_MEM_LOG_DIRTY_PAGES);
403
404 *current_stage = KVM_UPDATE_MAPPINGS;
405
406 clock_gettime(CLOCK_MONOTONIC_RAW, &start);
407 vcpus_complete_new_stage(*current_stage);
408 ts_diff = timespec_elapsed(start);
409
410 pr_info("KVM_UPDATE_MAPPINGS: total execution time: %ld.%.9lds\n\n",
411 ts_diff.tv_sec, ts_diff.tv_nsec);
412
413 /* Test the stage of KVM adjusting mappings */
414 vm_mem_region_set_flags(vm, TEST_MEM_SLOT_INDEX, 0);
415
416 *current_stage = KVM_ADJUST_MAPPINGS;
417
418 clock_gettime(CLOCK_MONOTONIC_RAW, &start);
419 vcpus_complete_new_stage(*current_stage);
420 ts_diff = timespec_elapsed(start);
421
422 pr_info("KVM_ADJUST_MAPPINGS: total execution time: %ld.%.9lds\n\n",
423 ts_diff.tv_sec, ts_diff.tv_nsec);
424
425 /* Tell the vcpu thread to quit */
426 host_quit = true;
427 for (vcpu_id = 0; vcpu_id < nr_vcpus; vcpu_id++) {
428 ret = sem_post(&test_stage_updated);
429 TEST_ASSERT(ret == 0, "Error in sem_post");
430 }
431
432 for (vcpu_id = 0; vcpu_id < nr_vcpus; vcpu_id++)
433 pthread_join(vcpu_threads[vcpu_id], NULL);
434
435 ret = sem_destroy(&test_stage_updated);
436 TEST_ASSERT(ret == 0, "Error in sem_destroy");
437
438 ret = sem_destroy(&test_stage_completed);
439 TEST_ASSERT(ret == 0, "Error in sem_destroy");
440
441 free(vcpu_threads);
442 ucall_uninit(vm);
443 kvm_vm_free(vm);
444 }
445
help(char * name)446 static void help(char *name)
447 {
448 puts("");
449 printf("usage: %s [-h] [-p offset] [-m mode] "
450 "[-b mem-size] [-v vcpus] [-s mem-type]\n", name);
451 puts("");
452 printf(" -p: specify guest physical test memory offset\n"
453 " Warning: a low offset can conflict with the loaded test code.\n");
454 guest_modes_help();
455 printf(" -b: specify size of the memory region for testing. e.g. 10M or 3G.\n"
456 " (default: 1G)\n");
457 printf(" -v: specify the number of vCPUs to run\n"
458 " (default: 1)\n");
459 backing_src_help("-s");
460 puts("");
461 }
462
main(int argc,char * argv[])463 int main(int argc, char *argv[])
464 {
465 int max_vcpus = kvm_check_cap(KVM_CAP_MAX_VCPUS);
466 struct test_params p = {
467 .test_mem_size = DEFAULT_TEST_MEM_SIZE,
468 .src_type = DEFAULT_VM_MEM_SRC,
469 };
470 int opt;
471
472 guest_modes_append_default();
473
474 while ((opt = getopt(argc, argv, "hp:m:b:v:s:")) != -1) {
475 switch (opt) {
476 case 'p':
477 p.phys_offset = strtoull(optarg, NULL, 0);
478 break;
479 case 'm':
480 guest_modes_cmdline(optarg);
481 break;
482 case 'b':
483 p.test_mem_size = parse_size(optarg);
484 break;
485 case 'v':
486 nr_vcpus = atoi(optarg);
487 TEST_ASSERT(nr_vcpus > 0 && nr_vcpus <= max_vcpus,
488 "Invalid number of vcpus, must be between 1 and %d", max_vcpus);
489 break;
490 case 's':
491 p.src_type = parse_backing_src_type(optarg);
492 break;
493 case 'h':
494 default:
495 help(argv[0]);
496 exit(0);
497 }
498 }
499
500 for_each_guest_mode(run_test, &p);
501
502 return 0;
503 }
504