1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * KVM dirty page logging test
4 *
5 * Copyright (C) 2018, Red Hat, Inc.
6 */
7 #include <stdio.h>
8 #include <stdlib.h>
9 #include <pthread.h>
10 #include <semaphore.h>
11 #include <sys/types.h>
12 #include <signal.h>
13 #include <errno.h>
14 #include <linux/bitmap.h>
15 #include <linux/bitops.h>
16 #include <linux/atomic.h>
17 #include <asm/barrier.h>
18
19 #include "kvm_util.h"
20 #include "test_util.h"
21 #include "guest_modes.h"
22 #include "processor.h"
23 #include "ucall_common.h"
24
25 #define DIRTY_MEM_BITS 30 /* 1G */
26 #define PAGE_SHIFT_4K 12
27
28 /* The memory slot index to track dirty pages */
29 #define TEST_MEM_SLOT_INDEX 1
30
31 /* Default guest test virtual memory offset */
32 #define DEFAULT_GUEST_TEST_MEM 0xc0000000
33
34 /* How many pages to dirty for each guest loop */
35 #define TEST_PAGES_PER_LOOP 1024
36
37 /* How many host loops to run (one KVM_GET_DIRTY_LOG for each loop) */
38 #define TEST_HOST_LOOP_N 32UL
39
40 /* Interval for each host loop (ms) */
41 #define TEST_HOST_LOOP_INTERVAL 10UL
42
43 /* Dirty bitmaps are always little endian, so we need to swap on big endian */
44 #if defined(__s390x__)
45 # define BITOP_LE_SWIZZLE ((BITS_PER_LONG-1) & ~0x7)
46 # define test_bit_le(nr, addr) \
47 test_bit((nr) ^ BITOP_LE_SWIZZLE, addr)
48 # define __set_bit_le(nr, addr) \
49 __set_bit((nr) ^ BITOP_LE_SWIZZLE, addr)
50 # define __clear_bit_le(nr, addr) \
51 __clear_bit((nr) ^ BITOP_LE_SWIZZLE, addr)
52 # define __test_and_set_bit_le(nr, addr) \
53 __test_and_set_bit((nr) ^ BITOP_LE_SWIZZLE, addr)
54 # define __test_and_clear_bit_le(nr, addr) \
55 __test_and_clear_bit((nr) ^ BITOP_LE_SWIZZLE, addr)
56 #else
57 # define test_bit_le test_bit
58 # define __set_bit_le __set_bit
59 # define __clear_bit_le __clear_bit
60 # define __test_and_set_bit_le __test_and_set_bit
61 # define __test_and_clear_bit_le __test_and_clear_bit
62 #endif
63
64 #define TEST_DIRTY_RING_COUNT 65536
65
66 #define SIG_IPI SIGUSR1
67
68 /*
69 * Guest/Host shared variables. Ensure addr_gva2hva() and/or
70 * sync_global_to/from_guest() are used when accessing from
71 * the host. READ/WRITE_ONCE() should also be used with anything
72 * that may change.
73 */
74 static uint64_t host_page_size;
75 static uint64_t guest_page_size;
76 static uint64_t guest_num_pages;
77 static uint64_t iteration;
78
79 /*
80 * Guest physical memory offset of the testing memory slot.
81 * This will be set to the topmost valid physical address minus
82 * the test memory size.
83 */
84 static uint64_t guest_test_phys_mem;
85
86 /*
87 * Guest virtual memory offset of the testing memory slot.
88 * Must not conflict with identity mapped test code.
89 */
90 static uint64_t guest_test_virt_mem = DEFAULT_GUEST_TEST_MEM;
91
92 /*
93 * Continuously write to the first 8 bytes of a random pages within
94 * the testing memory region.
95 */
guest_code(void)96 static void guest_code(void)
97 {
98 uint64_t addr;
99 int i;
100
101 /*
102 * On s390x, all pages of a 1M segment are initially marked as dirty
103 * when a page of the segment is written to for the very first time.
104 * To compensate this specialty in this test, we need to touch all
105 * pages during the first iteration.
106 */
107 for (i = 0; i < guest_num_pages; i++) {
108 addr = guest_test_virt_mem + i * guest_page_size;
109 vcpu_arch_put_guest(*(uint64_t *)addr, READ_ONCE(iteration));
110 }
111
112 while (true) {
113 for (i = 0; i < TEST_PAGES_PER_LOOP; i++) {
114 addr = guest_test_virt_mem;
115 addr += (guest_random_u64(&guest_rng) % guest_num_pages)
116 * guest_page_size;
117 addr = align_down(addr, host_page_size);
118
119 vcpu_arch_put_guest(*(uint64_t *)addr, READ_ONCE(iteration));
120 }
121
122 GUEST_SYNC(1);
123 }
124 }
125
126 /* Host variables */
127 static bool host_quit;
128
129 /* Points to the test VM memory region on which we track dirty logs */
130 static void *host_test_mem;
131 static uint64_t host_num_pages;
132
133 /* For statistics only */
134 static uint64_t host_dirty_count;
135 static uint64_t host_clear_count;
136 static uint64_t host_track_next_count;
137
138 /* Whether dirty ring reset is requested, or finished */
139 static sem_t sem_vcpu_stop;
140 static sem_t sem_vcpu_cont;
141 /*
142 * This is only set by main thread, and only cleared by vcpu thread. It is
143 * used to request vcpu thread to stop at the next GUEST_SYNC, since GUEST_SYNC
144 * is the only place that we'll guarantee both "dirty bit" and "dirty data"
145 * will match. E.g., SIG_IPI won't guarantee that if the vcpu is interrupted
146 * after setting dirty bit but before the data is written.
147 */
148 static atomic_t vcpu_sync_stop_requested;
149 /*
150 * This is updated by the vcpu thread to tell the host whether it's a
151 * ring-full event. It should only be read until a sem_wait() of
152 * sem_vcpu_stop and before vcpu continues to run.
153 */
154 static bool dirty_ring_vcpu_ring_full;
155 /*
156 * This is only used for verifying the dirty pages. Dirty ring has a very
157 * tricky case when the ring just got full, kvm will do userspace exit due to
158 * ring full. When that happens, the very last PFN is set but actually the
159 * data is not changed (the guest WRITE is not really applied yet), because
160 * we found that the dirty ring is full, refused to continue the vcpu, and
161 * recorded the dirty gfn with the old contents.
162 *
163 * For this specific case, it's safe to skip checking this pfn for this
164 * bit, because it's a redundant bit, and when the write happens later the bit
165 * will be set again. We use this variable to always keep track of the latest
166 * dirty gfn we've collected, so that if a mismatch of data found later in the
167 * verifying process, we let it pass.
168 */
169 static uint64_t dirty_ring_last_page;
170
171 enum log_mode_t {
172 /* Only use KVM_GET_DIRTY_LOG for logging */
173 LOG_MODE_DIRTY_LOG = 0,
174
175 /* Use both KVM_[GET|CLEAR]_DIRTY_LOG for logging */
176 LOG_MODE_CLEAR_LOG = 1,
177
178 /* Use dirty ring for logging */
179 LOG_MODE_DIRTY_RING = 2,
180
181 LOG_MODE_NUM,
182
183 /* Run all supported modes */
184 LOG_MODE_ALL = LOG_MODE_NUM,
185 };
186
187 /* Mode of logging to test. Default is to run all supported modes */
188 static enum log_mode_t host_log_mode_option = LOG_MODE_ALL;
189 /* Logging mode for current run */
190 static enum log_mode_t host_log_mode;
191 static pthread_t vcpu_thread;
192 static uint32_t test_dirty_ring_count = TEST_DIRTY_RING_COUNT;
193
vcpu_kick(void)194 static void vcpu_kick(void)
195 {
196 pthread_kill(vcpu_thread, SIG_IPI);
197 }
198
199 /*
200 * In our test we do signal tricks, let's use a better version of
201 * sem_wait to avoid signal interrupts
202 */
sem_wait_until(sem_t * sem)203 static void sem_wait_until(sem_t *sem)
204 {
205 int ret;
206
207 do
208 ret = sem_wait(sem);
209 while (ret == -1 && errno == EINTR);
210 }
211
clear_log_supported(void)212 static bool clear_log_supported(void)
213 {
214 return kvm_has_cap(KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2);
215 }
216
clear_log_create_vm_done(struct kvm_vm * vm)217 static void clear_log_create_vm_done(struct kvm_vm *vm)
218 {
219 u64 manual_caps;
220
221 manual_caps = kvm_check_cap(KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2);
222 TEST_ASSERT(manual_caps, "MANUAL_CAPS is zero!");
223 manual_caps &= (KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE |
224 KVM_DIRTY_LOG_INITIALLY_SET);
225 vm_enable_cap(vm, KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2, manual_caps);
226 }
227
dirty_log_collect_dirty_pages(struct kvm_vcpu * vcpu,int slot,void * bitmap,uint32_t num_pages,uint32_t * unused)228 static void dirty_log_collect_dirty_pages(struct kvm_vcpu *vcpu, int slot,
229 void *bitmap, uint32_t num_pages,
230 uint32_t *unused)
231 {
232 kvm_vm_get_dirty_log(vcpu->vm, slot, bitmap);
233 }
234
clear_log_collect_dirty_pages(struct kvm_vcpu * vcpu,int slot,void * bitmap,uint32_t num_pages,uint32_t * unused)235 static void clear_log_collect_dirty_pages(struct kvm_vcpu *vcpu, int slot,
236 void *bitmap, uint32_t num_pages,
237 uint32_t *unused)
238 {
239 kvm_vm_get_dirty_log(vcpu->vm, slot, bitmap);
240 kvm_vm_clear_dirty_log(vcpu->vm, slot, bitmap, 0, num_pages);
241 }
242
243 /* Should only be called after a GUEST_SYNC */
vcpu_handle_sync_stop(void)244 static void vcpu_handle_sync_stop(void)
245 {
246 if (atomic_read(&vcpu_sync_stop_requested)) {
247 /* It means main thread is sleeping waiting */
248 atomic_set(&vcpu_sync_stop_requested, false);
249 sem_post(&sem_vcpu_stop);
250 sem_wait_until(&sem_vcpu_cont);
251 }
252 }
253
default_after_vcpu_run(struct kvm_vcpu * vcpu,int ret,int err)254 static void default_after_vcpu_run(struct kvm_vcpu *vcpu, int ret, int err)
255 {
256 struct kvm_run *run = vcpu->run;
257
258 TEST_ASSERT(ret == 0 || (ret == -1 && err == EINTR),
259 "vcpu run failed: errno=%d", err);
260
261 TEST_ASSERT(get_ucall(vcpu, NULL) == UCALL_SYNC,
262 "Invalid guest sync status: exit_reason=%s",
263 exit_reason_str(run->exit_reason));
264
265 vcpu_handle_sync_stop();
266 }
267
dirty_ring_supported(void)268 static bool dirty_ring_supported(void)
269 {
270 return (kvm_has_cap(KVM_CAP_DIRTY_LOG_RING) ||
271 kvm_has_cap(KVM_CAP_DIRTY_LOG_RING_ACQ_REL));
272 }
273
dirty_ring_create_vm_done(struct kvm_vm * vm)274 static void dirty_ring_create_vm_done(struct kvm_vm *vm)
275 {
276 uint64_t pages;
277 uint32_t limit;
278
279 /*
280 * We rely on vcpu exit due to full dirty ring state. Adjust
281 * the ring buffer size to ensure we're able to reach the
282 * full dirty ring state.
283 */
284 pages = (1ul << (DIRTY_MEM_BITS - vm->page_shift)) + 3;
285 pages = vm_adjust_num_guest_pages(vm->mode, pages);
286 if (vm->page_size < getpagesize())
287 pages = vm_num_host_pages(vm->mode, pages);
288
289 limit = 1 << (31 - __builtin_clz(pages));
290 test_dirty_ring_count = 1 << (31 - __builtin_clz(test_dirty_ring_count));
291 test_dirty_ring_count = min(limit, test_dirty_ring_count);
292 pr_info("dirty ring count: 0x%x\n", test_dirty_ring_count);
293
294 /*
295 * Switch to dirty ring mode after VM creation but before any
296 * of the vcpu creation.
297 */
298 vm_enable_dirty_ring(vm, test_dirty_ring_count *
299 sizeof(struct kvm_dirty_gfn));
300 }
301
dirty_gfn_is_dirtied(struct kvm_dirty_gfn * gfn)302 static inline bool dirty_gfn_is_dirtied(struct kvm_dirty_gfn *gfn)
303 {
304 return smp_load_acquire(&gfn->flags) == KVM_DIRTY_GFN_F_DIRTY;
305 }
306
dirty_gfn_set_collected(struct kvm_dirty_gfn * gfn)307 static inline void dirty_gfn_set_collected(struct kvm_dirty_gfn *gfn)
308 {
309 smp_store_release(&gfn->flags, KVM_DIRTY_GFN_F_RESET);
310 }
311
dirty_ring_collect_one(struct kvm_dirty_gfn * dirty_gfns,int slot,void * bitmap,uint32_t num_pages,uint32_t * fetch_index)312 static uint32_t dirty_ring_collect_one(struct kvm_dirty_gfn *dirty_gfns,
313 int slot, void *bitmap,
314 uint32_t num_pages, uint32_t *fetch_index)
315 {
316 struct kvm_dirty_gfn *cur;
317 uint32_t count = 0;
318
319 while (true) {
320 cur = &dirty_gfns[*fetch_index % test_dirty_ring_count];
321 if (!dirty_gfn_is_dirtied(cur))
322 break;
323 TEST_ASSERT(cur->slot == slot, "Slot number didn't match: "
324 "%u != %u", cur->slot, slot);
325 TEST_ASSERT(cur->offset < num_pages, "Offset overflow: "
326 "0x%llx >= 0x%x", cur->offset, num_pages);
327 //pr_info("fetch 0x%x page %llu\n", *fetch_index, cur->offset);
328 __set_bit_le(cur->offset, bitmap);
329 dirty_ring_last_page = cur->offset;
330 dirty_gfn_set_collected(cur);
331 (*fetch_index)++;
332 count++;
333 }
334
335 return count;
336 }
337
dirty_ring_wait_vcpu(void)338 static void dirty_ring_wait_vcpu(void)
339 {
340 /* This makes sure that hardware PML cache flushed */
341 vcpu_kick();
342 sem_wait_until(&sem_vcpu_stop);
343 }
344
dirty_ring_continue_vcpu(void)345 static void dirty_ring_continue_vcpu(void)
346 {
347 pr_info("Notifying vcpu to continue\n");
348 sem_post(&sem_vcpu_cont);
349 }
350
dirty_ring_collect_dirty_pages(struct kvm_vcpu * vcpu,int slot,void * bitmap,uint32_t num_pages,uint32_t * ring_buf_idx)351 static void dirty_ring_collect_dirty_pages(struct kvm_vcpu *vcpu, int slot,
352 void *bitmap, uint32_t num_pages,
353 uint32_t *ring_buf_idx)
354 {
355 uint32_t count = 0, cleared;
356 bool continued_vcpu = false;
357
358 dirty_ring_wait_vcpu();
359
360 if (!dirty_ring_vcpu_ring_full) {
361 /*
362 * This is not a ring-full event, it's safe to allow
363 * vcpu to continue
364 */
365 dirty_ring_continue_vcpu();
366 continued_vcpu = true;
367 }
368
369 /* Only have one vcpu */
370 count = dirty_ring_collect_one(vcpu_map_dirty_ring(vcpu),
371 slot, bitmap, num_pages,
372 ring_buf_idx);
373
374 cleared = kvm_vm_reset_dirty_ring(vcpu->vm);
375
376 /*
377 * Cleared pages should be the same as collected, as KVM is supposed to
378 * clear only the entries that have been harvested.
379 */
380 TEST_ASSERT(cleared == count, "Reset dirty pages (%u) mismatch "
381 "with collected (%u)", cleared, count);
382
383 if (!continued_vcpu) {
384 TEST_ASSERT(dirty_ring_vcpu_ring_full,
385 "Didn't continue vcpu even without ring full");
386 dirty_ring_continue_vcpu();
387 }
388
389 pr_info("Iteration %ld collected %u pages\n", iteration, count);
390 }
391
dirty_ring_after_vcpu_run(struct kvm_vcpu * vcpu,int ret,int err)392 static void dirty_ring_after_vcpu_run(struct kvm_vcpu *vcpu, int ret, int err)
393 {
394 struct kvm_run *run = vcpu->run;
395
396 /* A ucall-sync or ring-full event is allowed */
397 if (get_ucall(vcpu, NULL) == UCALL_SYNC) {
398 /* We should allow this to continue */
399 ;
400 } else if (run->exit_reason == KVM_EXIT_DIRTY_RING_FULL ||
401 (ret == -1 && err == EINTR)) {
402 /* Update the flag first before pause */
403 WRITE_ONCE(dirty_ring_vcpu_ring_full,
404 run->exit_reason == KVM_EXIT_DIRTY_RING_FULL);
405 sem_post(&sem_vcpu_stop);
406 pr_info("vcpu stops because %s...\n",
407 dirty_ring_vcpu_ring_full ?
408 "dirty ring is full" : "vcpu is kicked out");
409 sem_wait_until(&sem_vcpu_cont);
410 pr_info("vcpu continues now.\n");
411 } else {
412 TEST_ASSERT(false, "Invalid guest sync status: "
413 "exit_reason=%s",
414 exit_reason_str(run->exit_reason));
415 }
416 }
417
418 struct log_mode {
419 const char *name;
420 /* Return true if this mode is supported, otherwise false */
421 bool (*supported)(void);
422 /* Hook when the vm creation is done (before vcpu creation) */
423 void (*create_vm_done)(struct kvm_vm *vm);
424 /* Hook to collect the dirty pages into the bitmap provided */
425 void (*collect_dirty_pages) (struct kvm_vcpu *vcpu, int slot,
426 void *bitmap, uint32_t num_pages,
427 uint32_t *ring_buf_idx);
428 /* Hook to call when after each vcpu run */
429 void (*after_vcpu_run)(struct kvm_vcpu *vcpu, int ret, int err);
430 } log_modes[LOG_MODE_NUM] = {
431 {
432 .name = "dirty-log",
433 .collect_dirty_pages = dirty_log_collect_dirty_pages,
434 .after_vcpu_run = default_after_vcpu_run,
435 },
436 {
437 .name = "clear-log",
438 .supported = clear_log_supported,
439 .create_vm_done = clear_log_create_vm_done,
440 .collect_dirty_pages = clear_log_collect_dirty_pages,
441 .after_vcpu_run = default_after_vcpu_run,
442 },
443 {
444 .name = "dirty-ring",
445 .supported = dirty_ring_supported,
446 .create_vm_done = dirty_ring_create_vm_done,
447 .collect_dirty_pages = dirty_ring_collect_dirty_pages,
448 .after_vcpu_run = dirty_ring_after_vcpu_run,
449 },
450 };
451
452 /*
453 * We use this bitmap to track some pages that should have its dirty
454 * bit set in the _next_ iteration. For example, if we detected the
455 * page value changed to current iteration but at the same time the
456 * page bit is cleared in the latest bitmap, then the system must
457 * report that write in the next get dirty log call.
458 */
459 static unsigned long *host_bmap_track;
460
log_modes_dump(void)461 static void log_modes_dump(void)
462 {
463 int i;
464
465 printf("all");
466 for (i = 0; i < LOG_MODE_NUM; i++)
467 printf(", %s", log_modes[i].name);
468 printf("\n");
469 }
470
log_mode_supported(void)471 static bool log_mode_supported(void)
472 {
473 struct log_mode *mode = &log_modes[host_log_mode];
474
475 if (mode->supported)
476 return mode->supported();
477
478 return true;
479 }
480
log_mode_create_vm_done(struct kvm_vm * vm)481 static void log_mode_create_vm_done(struct kvm_vm *vm)
482 {
483 struct log_mode *mode = &log_modes[host_log_mode];
484
485 if (mode->create_vm_done)
486 mode->create_vm_done(vm);
487 }
488
log_mode_collect_dirty_pages(struct kvm_vcpu * vcpu,int slot,void * bitmap,uint32_t num_pages,uint32_t * ring_buf_idx)489 static void log_mode_collect_dirty_pages(struct kvm_vcpu *vcpu, int slot,
490 void *bitmap, uint32_t num_pages,
491 uint32_t *ring_buf_idx)
492 {
493 struct log_mode *mode = &log_modes[host_log_mode];
494
495 TEST_ASSERT(mode->collect_dirty_pages != NULL,
496 "collect_dirty_pages() is required for any log mode!");
497 mode->collect_dirty_pages(vcpu, slot, bitmap, num_pages, ring_buf_idx);
498 }
499
log_mode_after_vcpu_run(struct kvm_vcpu * vcpu,int ret,int err)500 static void log_mode_after_vcpu_run(struct kvm_vcpu *vcpu, int ret, int err)
501 {
502 struct log_mode *mode = &log_modes[host_log_mode];
503
504 if (mode->after_vcpu_run)
505 mode->after_vcpu_run(vcpu, ret, err);
506 }
507
vcpu_worker(void * data)508 static void *vcpu_worker(void *data)
509 {
510 int ret;
511 struct kvm_vcpu *vcpu = data;
512 uint64_t pages_count = 0;
513 struct kvm_signal_mask *sigmask = alloca(offsetof(struct kvm_signal_mask, sigset)
514 + sizeof(sigset_t));
515 sigset_t *sigset = (sigset_t *) &sigmask->sigset;
516
517 /*
518 * SIG_IPI is unblocked atomically while in KVM_RUN. It causes the
519 * ioctl to return with -EINTR, but it is still pending and we need
520 * to accept it with the sigwait.
521 */
522 sigmask->len = 8;
523 pthread_sigmask(0, NULL, sigset);
524 sigdelset(sigset, SIG_IPI);
525 vcpu_ioctl(vcpu, KVM_SET_SIGNAL_MASK, sigmask);
526
527 sigemptyset(sigset);
528 sigaddset(sigset, SIG_IPI);
529
530 while (!READ_ONCE(host_quit)) {
531 /* Clear any existing kick signals */
532 pages_count += TEST_PAGES_PER_LOOP;
533 /* Let the guest dirty the random pages */
534 ret = __vcpu_run(vcpu);
535 if (ret == -1 && errno == EINTR) {
536 int sig = -1;
537 sigwait(sigset, &sig);
538 assert(sig == SIG_IPI);
539 }
540 log_mode_after_vcpu_run(vcpu, ret, errno);
541 }
542
543 pr_info("Dirtied %"PRIu64" pages\n", pages_count);
544
545 return NULL;
546 }
547
vm_dirty_log_verify(enum vm_guest_mode mode,unsigned long * bmap)548 static void vm_dirty_log_verify(enum vm_guest_mode mode, unsigned long *bmap)
549 {
550 uint64_t step = vm_num_host_pages(mode, 1);
551 uint64_t page;
552 uint64_t *value_ptr;
553 uint64_t min_iter = 0;
554
555 for (page = 0; page < host_num_pages; page += step) {
556 value_ptr = host_test_mem + page * host_page_size;
557
558 /* If this is a special page that we were tracking... */
559 if (__test_and_clear_bit_le(page, host_bmap_track)) {
560 host_track_next_count++;
561 TEST_ASSERT(test_bit_le(page, bmap),
562 "Page %"PRIu64" should have its dirty bit "
563 "set in this iteration but it is missing",
564 page);
565 }
566
567 if (__test_and_clear_bit_le(page, bmap)) {
568 bool matched;
569
570 host_dirty_count++;
571
572 /*
573 * If the bit is set, the value written onto
574 * the corresponding page should be either the
575 * previous iteration number or the current one.
576 */
577 matched = (*value_ptr == iteration ||
578 *value_ptr == iteration - 1);
579
580 if (host_log_mode == LOG_MODE_DIRTY_RING && !matched) {
581 if (*value_ptr == iteration - 2 && min_iter <= iteration - 2) {
582 /*
583 * Short answer: this case is special
584 * only for dirty ring test where the
585 * page is the last page before a kvm
586 * dirty ring full in iteration N-2.
587 *
588 * Long answer: Assuming ring size R,
589 * one possible condition is:
590 *
591 * main thr vcpu thr
592 * -------- --------
593 * iter=1
594 * write 1 to page 0~(R-1)
595 * full, vmexit
596 * collect 0~(R-1)
597 * kick vcpu
598 * write 1 to (R-1)~(2R-2)
599 * full, vmexit
600 * iter=2
601 * collect (R-1)~(2R-2)
602 * kick vcpu
603 * write 1 to (2R-2)
604 * (NOTE!!! "1" cached in cpu reg)
605 * write 2 to (2R-1)~(3R-3)
606 * full, vmexit
607 * iter=3
608 * collect (2R-2)~(3R-3)
609 * (here if we read value on page
610 * "2R-2" is 1, while iter=3!!!)
611 *
612 * This however can only happen once per iteration.
613 */
614 min_iter = iteration - 1;
615 continue;
616 } else if (page == dirty_ring_last_page) {
617 /*
618 * Please refer to comments in
619 * dirty_ring_last_page.
620 */
621 continue;
622 }
623 }
624
625 TEST_ASSERT(matched,
626 "Set page %"PRIu64" value %"PRIu64
627 " incorrect (iteration=%"PRIu64")",
628 page, *value_ptr, iteration);
629 } else {
630 host_clear_count++;
631 /*
632 * If cleared, the value written can be any
633 * value smaller or equals to the iteration
634 * number. Note that the value can be exactly
635 * (iteration-1) if that write can happen
636 * like this:
637 *
638 * (1) increase loop count to "iteration-1"
639 * (2) write to page P happens (with value
640 * "iteration-1")
641 * (3) get dirty log for "iteration-1"; we'll
642 * see that page P bit is set (dirtied),
643 * and not set the bit in host_bmap_track
644 * (4) increase loop count to "iteration"
645 * (which is current iteration)
646 * (5) get dirty log for current iteration,
647 * we'll see that page P is cleared, with
648 * value "iteration-1".
649 */
650 TEST_ASSERT(*value_ptr <= iteration,
651 "Clear page %"PRIu64" value %"PRIu64
652 " incorrect (iteration=%"PRIu64")",
653 page, *value_ptr, iteration);
654 if (*value_ptr == iteration) {
655 /*
656 * This page is _just_ modified; it
657 * should report its dirtyness in the
658 * next run
659 */
660 __set_bit_le(page, host_bmap_track);
661 }
662 }
663 }
664 }
665
create_vm(enum vm_guest_mode mode,struct kvm_vcpu ** vcpu,uint64_t extra_mem_pages,void * guest_code)666 static struct kvm_vm *create_vm(enum vm_guest_mode mode, struct kvm_vcpu **vcpu,
667 uint64_t extra_mem_pages, void *guest_code)
668 {
669 struct kvm_vm *vm;
670
671 pr_info("Testing guest mode: %s\n", vm_guest_mode_string(mode));
672
673 vm = __vm_create(VM_SHAPE(mode), 1, extra_mem_pages);
674
675 log_mode_create_vm_done(vm);
676 *vcpu = vm_vcpu_add(vm, 0, guest_code);
677 return vm;
678 }
679
680 struct test_params {
681 unsigned long iterations;
682 unsigned long interval;
683 uint64_t phys_offset;
684 };
685
run_test(enum vm_guest_mode mode,void * arg)686 static void run_test(enum vm_guest_mode mode, void *arg)
687 {
688 struct test_params *p = arg;
689 struct kvm_vcpu *vcpu;
690 struct kvm_vm *vm;
691 unsigned long *bmap;
692 uint32_t ring_buf_idx = 0;
693 int sem_val;
694
695 if (!log_mode_supported()) {
696 print_skip("Log mode '%s' not supported",
697 log_modes[host_log_mode].name);
698 return;
699 }
700
701 /*
702 * We reserve page table for 2 times of extra dirty mem which
703 * will definitely cover the original (1G+) test range. Here
704 * we do the calculation with 4K page size which is the
705 * smallest so the page number will be enough for all archs
706 * (e.g., 64K page size guest will need even less memory for
707 * page tables).
708 */
709 vm = create_vm(mode, &vcpu,
710 2ul << (DIRTY_MEM_BITS - PAGE_SHIFT_4K), guest_code);
711
712 guest_page_size = vm->page_size;
713 /*
714 * A little more than 1G of guest page sized pages. Cover the
715 * case where the size is not aligned to 64 pages.
716 */
717 guest_num_pages = (1ul << (DIRTY_MEM_BITS - vm->page_shift)) + 3;
718 guest_num_pages = vm_adjust_num_guest_pages(mode, guest_num_pages);
719
720 host_page_size = getpagesize();
721 host_num_pages = vm_num_host_pages(mode, guest_num_pages);
722
723 if (!p->phys_offset) {
724 guest_test_phys_mem = (vm->max_gfn - guest_num_pages) *
725 guest_page_size;
726 guest_test_phys_mem = align_down(guest_test_phys_mem, host_page_size);
727 } else {
728 guest_test_phys_mem = p->phys_offset;
729 }
730
731 #ifdef __s390x__
732 /* Align to 1M (segment size) */
733 guest_test_phys_mem = align_down(guest_test_phys_mem, 1 << 20);
734 #endif
735
736 pr_info("guest physical test memory offset: 0x%lx\n", guest_test_phys_mem);
737
738 bmap = bitmap_zalloc(host_num_pages);
739 host_bmap_track = bitmap_zalloc(host_num_pages);
740
741 /* Add an extra memory slot for testing dirty logging */
742 vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS,
743 guest_test_phys_mem,
744 TEST_MEM_SLOT_INDEX,
745 guest_num_pages,
746 KVM_MEM_LOG_DIRTY_PAGES);
747
748 /* Do mapping for the dirty track memory slot */
749 virt_map(vm, guest_test_virt_mem, guest_test_phys_mem, guest_num_pages);
750
751 /* Cache the HVA pointer of the region */
752 host_test_mem = addr_gpa2hva(vm, (vm_paddr_t)guest_test_phys_mem);
753
754 /* Export the shared variables to the guest */
755 sync_global_to_guest(vm, host_page_size);
756 sync_global_to_guest(vm, guest_page_size);
757 sync_global_to_guest(vm, guest_test_virt_mem);
758 sync_global_to_guest(vm, guest_num_pages);
759
760 /* Start the iterations */
761 iteration = 1;
762 sync_global_to_guest(vm, iteration);
763 WRITE_ONCE(host_quit, false);
764 host_dirty_count = 0;
765 host_clear_count = 0;
766 host_track_next_count = 0;
767 WRITE_ONCE(dirty_ring_vcpu_ring_full, false);
768
769 /*
770 * Ensure the previous iteration didn't leave a dangling semaphore, i.e.
771 * that the main task and vCPU worker were synchronized and completed
772 * verification of all iterations.
773 */
774 sem_getvalue(&sem_vcpu_stop, &sem_val);
775 TEST_ASSERT_EQ(sem_val, 0);
776 sem_getvalue(&sem_vcpu_cont, &sem_val);
777 TEST_ASSERT_EQ(sem_val, 0);
778
779 pthread_create(&vcpu_thread, NULL, vcpu_worker, vcpu);
780
781 while (iteration < p->iterations) {
782 /* Give the vcpu thread some time to dirty some pages */
783 usleep(p->interval * 1000);
784 log_mode_collect_dirty_pages(vcpu, TEST_MEM_SLOT_INDEX,
785 bmap, host_num_pages,
786 &ring_buf_idx);
787
788 /*
789 * See vcpu_sync_stop_requested definition for details on why
790 * we need to stop vcpu when verify data.
791 */
792 atomic_set(&vcpu_sync_stop_requested, true);
793 sem_wait_until(&sem_vcpu_stop);
794 /*
795 * NOTE: for dirty ring, it's possible that we didn't stop at
796 * GUEST_SYNC but instead we stopped because ring is full;
797 * that's okay too because ring full means we're only missing
798 * the flush of the last page, and since we handle the last
799 * page specially verification will succeed anyway.
800 */
801 assert(host_log_mode == LOG_MODE_DIRTY_RING ||
802 atomic_read(&vcpu_sync_stop_requested) == false);
803 vm_dirty_log_verify(mode, bmap);
804
805 /*
806 * Set host_quit before sem_vcpu_cont in the final iteration to
807 * ensure that the vCPU worker doesn't resume the guest. As
808 * above, the dirty ring test may stop and wait even when not
809 * explicitly request to do so, i.e. would hang waiting for a
810 * "continue" if it's allowed to resume the guest.
811 */
812 if (++iteration == p->iterations)
813 WRITE_ONCE(host_quit, true);
814
815 sem_post(&sem_vcpu_cont);
816 sync_global_to_guest(vm, iteration);
817 }
818
819 pthread_join(vcpu_thread, NULL);
820
821 pr_info("Total bits checked: dirty (%"PRIu64"), clear (%"PRIu64"), "
822 "track_next (%"PRIu64")\n", host_dirty_count, host_clear_count,
823 host_track_next_count);
824
825 free(bmap);
826 free(host_bmap_track);
827 kvm_vm_free(vm);
828 }
829
help(char * name)830 static void help(char *name)
831 {
832 puts("");
833 printf("usage: %s [-h] [-i iterations] [-I interval] "
834 "[-p offset] [-m mode]\n", name);
835 puts("");
836 printf(" -c: hint to dirty ring size, in number of entries\n");
837 printf(" (only useful for dirty-ring test; default: %"PRIu32")\n",
838 TEST_DIRTY_RING_COUNT);
839 printf(" -i: specify iteration counts (default: %"PRIu64")\n",
840 TEST_HOST_LOOP_N);
841 printf(" -I: specify interval in ms (default: %"PRIu64" ms)\n",
842 TEST_HOST_LOOP_INTERVAL);
843 printf(" -p: specify guest physical test memory offset\n"
844 " Warning: a low offset can conflict with the loaded test code.\n");
845 printf(" -M: specify the host logging mode "
846 "(default: run all log modes). Supported modes: \n\t");
847 log_modes_dump();
848 guest_modes_help();
849 puts("");
850 exit(0);
851 }
852
main(int argc,char * argv[])853 int main(int argc, char *argv[])
854 {
855 struct test_params p = {
856 .iterations = TEST_HOST_LOOP_N,
857 .interval = TEST_HOST_LOOP_INTERVAL,
858 };
859 int opt, i;
860 sigset_t sigset;
861
862 sem_init(&sem_vcpu_stop, 0, 0);
863 sem_init(&sem_vcpu_cont, 0, 0);
864
865 guest_modes_append_default();
866
867 while ((opt = getopt(argc, argv, "c:hi:I:p:m:M:")) != -1) {
868 switch (opt) {
869 case 'c':
870 test_dirty_ring_count = strtol(optarg, NULL, 10);
871 break;
872 case 'i':
873 p.iterations = strtol(optarg, NULL, 10);
874 break;
875 case 'I':
876 p.interval = strtol(optarg, NULL, 10);
877 break;
878 case 'p':
879 p.phys_offset = strtoull(optarg, NULL, 0);
880 break;
881 case 'm':
882 guest_modes_cmdline(optarg);
883 break;
884 case 'M':
885 if (!strcmp(optarg, "all")) {
886 host_log_mode_option = LOG_MODE_ALL;
887 break;
888 }
889 for (i = 0; i < LOG_MODE_NUM; i++) {
890 if (!strcmp(optarg, log_modes[i].name)) {
891 pr_info("Setting log mode to: '%s'\n",
892 optarg);
893 host_log_mode_option = i;
894 break;
895 }
896 }
897 if (i == LOG_MODE_NUM) {
898 printf("Log mode '%s' invalid. Please choose "
899 "from: ", optarg);
900 log_modes_dump();
901 exit(1);
902 }
903 break;
904 case 'h':
905 default:
906 help(argv[0]);
907 break;
908 }
909 }
910
911 TEST_ASSERT(p.iterations > 2, "Iterations must be greater than two");
912 TEST_ASSERT(p.interval > 0, "Interval must be greater than zero");
913
914 pr_info("Test iterations: %"PRIu64", interval: %"PRIu64" (ms)\n",
915 p.iterations, p.interval);
916
917 srandom(time(0));
918
919 /* Ensure that vCPU threads start with SIG_IPI blocked. */
920 sigemptyset(&sigset);
921 sigaddset(&sigset, SIG_IPI);
922 pthread_sigmask(SIG_BLOCK, &sigset, NULL);
923
924 if (host_log_mode_option == LOG_MODE_ALL) {
925 /* Run each log mode */
926 for (i = 0; i < LOG_MODE_NUM; i++) {
927 pr_info("Testing Log Mode '%s'\n", log_modes[i].name);
928 host_log_mode = i;
929 for_each_guest_mode(run_test, &p);
930 }
931 } else {
932 host_log_mode = host_log_mode_option;
933 for_each_guest_mode(run_test, &p);
934 }
935
936 return 0;
937 }
938