1// SPDX-License-Identifier: GPL-2.0
2/*
3 * KVM dirty page logging test
4 *
5 * Copyright (C) 2018, Red Hat, Inc.
6 */
7
8#define _GNU_SOURCE /* for program_invocation_name */
9
10#include <stdio.h>
11#include <stdlib.h>
12#include <pthread.h>
13#include <semaphore.h>
14#include <sys/types.h>
15#include <signal.h>
16#include <errno.h>
17#include <linux/bitmap.h>
18#include <linux/bitops.h>
19#include <linux/atomic.h>
20#include <asm/barrier.h>
21
22#include "kvm_util.h"
23#include "test_util.h"
24#include "guest_modes.h"
25#include "processor.h"
26
27#define DIRTY_MEM_BITS 30 /* 1G */
28#define PAGE_SHIFT_4K 12
29
30/* The memory slot index to track dirty pages */
31#define TEST_MEM_SLOT_INDEX 1
32
33/* Default guest test virtual memory offset */
34#define DEFAULT_GUEST_TEST_MEM 0xc0000000
35
36/* How many pages to dirty for each guest loop */
37#define TEST_PAGES_PER_LOOP 1024
38
39/* How many host loops to run (one KVM_GET_DIRTY_LOG for each loop) */
40#define TEST_HOST_LOOP_N 32UL
41
42/* Interval for each host loop (ms) */
43#define TEST_HOST_LOOP_INTERVAL 10UL
44
45/* Dirty bitmaps are always little endian, so we need to swap on big endian */
46#if defined(__s390x__)
47# define BITOP_LE_SWIZZLE ((BITS_PER_LONG-1) & ~0x7)
48# define test_bit_le(nr, addr) \
49 test_bit((nr) ^ BITOP_LE_SWIZZLE, addr)
50# define __set_bit_le(nr, addr) \
51 __set_bit((nr) ^ BITOP_LE_SWIZZLE, addr)
52# define __clear_bit_le(nr, addr) \
53 __clear_bit((nr) ^ BITOP_LE_SWIZZLE, addr)
54# define __test_and_set_bit_le(nr, addr) \
55 __test_and_set_bit((nr) ^ BITOP_LE_SWIZZLE, addr)
56# define __test_and_clear_bit_le(nr, addr) \
57 __test_and_clear_bit((nr) ^ BITOP_LE_SWIZZLE, addr)
58#else
59# define test_bit_le test_bit
60# define __set_bit_le __set_bit
61# define __clear_bit_le __clear_bit
62# define __test_and_set_bit_le __test_and_set_bit
63# define __test_and_clear_bit_le __test_and_clear_bit
64#endif
65
66#define TEST_DIRTY_RING_COUNT 65536
67
68#define SIG_IPI SIGUSR1
69
70/*
71 * Guest/Host shared variables. Ensure addr_gva2hva() and/or
72 * sync_global_to/from_guest() are used when accessing from
73 * the host. READ/WRITE_ONCE() should also be used with anything
74 * that may change.
75 */
76static uint64_t host_page_size;
77static uint64_t guest_page_size;
78static uint64_t guest_num_pages;
79static uint64_t random_array[TEST_PAGES_PER_LOOP];
80static uint64_t iteration;
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 */
87static 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 */
93static uint64_t guest_test_virt_mem = DEFAULT_GUEST_TEST_MEM;
94
95/*
96 * Continuously write to the first 8 bytes of a random pages within
97 * the testing memory region.
98 */
99static void guest_code(void)
100{
101 uint64_t addr;
102 int i;
103
104 /*
105 * On s390x, all pages of a 1M segment are initially marked as dirty
106 * when a page of the segment is written to for the very first time.
107 * To compensate this specialty in this test, we need to touch all
108 * pages during the first iteration.
109 */
110 for (i = 0; i < guest_num_pages; i++) {
111 addr = guest_test_virt_mem + i * guest_page_size;
112 *(uint64_t *)addr = READ_ONCE(iteration);
113 }
114
115 while (true) {
116 for (i = 0; i < TEST_PAGES_PER_LOOP; i++) {
117 addr = guest_test_virt_mem;
118 addr += (READ_ONCE(random_array[i]) % guest_num_pages)
119 * guest_page_size;
120 addr = align_down(addr, host_page_size);
121 *(uint64_t *)addr = READ_ONCE(iteration);
122 }
123
124 /* Tell the host that we need more random numbers */
125 GUEST_SYNC(1);
126 }
127}
128
129/* Host variables */
130static bool host_quit;
131
132/* Points to the test VM memory region on which we track dirty logs */
133static void *host_test_mem;
134static uint64_t host_num_pages;
135
136/* For statistics only */
137static uint64_t host_dirty_count;
138static uint64_t host_clear_count;
139static uint64_t host_track_next_count;
140
141/* Whether dirty ring reset is requested, or finished */
142static sem_t sem_vcpu_stop;
143static sem_t sem_vcpu_cont;
144/*
145 * This is only set by main thread, and only cleared by vcpu thread. It is
146 * used to request vcpu thread to stop at the next GUEST_SYNC, since GUEST_SYNC
147 * is the only place that we'll guarantee both "dirty bit" and "dirty data"
148 * will match. E.g., SIG_IPI won't guarantee that if the vcpu is interrupted
149 * after setting dirty bit but before the data is written.
150 */
151static atomic_t vcpu_sync_stop_requested;
152/*
153 * This is updated by the vcpu thread to tell the host whether it's a
154 * ring-full event. It should only be read until a sem_wait() of
155 * sem_vcpu_stop and before vcpu continues to run.
156 */
157static bool dirty_ring_vcpu_ring_full;
158/*
159 * This is only used for verifying the dirty pages. Dirty ring has a very
160 * tricky case when the ring just got full, kvm will do userspace exit due to
161 * ring full. When that happens, the very last PFN is set but actually the
162 * data is not changed (the guest WRITE is not really applied yet), because
163 * we found that the dirty ring is full, refused to continue the vcpu, and
164 * recorded the dirty gfn with the old contents.
165 *
166 * For this specific case, it's safe to skip checking this pfn for this
167 * bit, because it's a redundant bit, and when the write happens later the bit
168 * will be set again. We use this variable to always keep track of the latest
169 * dirty gfn we've collected, so that if a mismatch of data found later in the
170 * verifying process, we let it pass.
171 */
172static uint64_t dirty_ring_last_page;
173
174enum log_mode_t {
175 /* Only use KVM_GET_DIRTY_LOG for logging */
176 LOG_MODE_DIRTY_LOG = 0,
177
178 /* Use both KVM_[GET|CLEAR]_DIRTY_LOG for logging */
179 LOG_MODE_CLEAR_LOG = 1,
180
181 /* Use dirty ring for logging */
182 LOG_MODE_DIRTY_RING = 2,
183
184 LOG_MODE_NUM,
185
186 /* Run all supported modes */
187 LOG_MODE_ALL = LOG_MODE_NUM,
188};
189
190/* Mode of logging to test. Default is to run all supported modes */
191static enum log_mode_t host_log_mode_option = LOG_MODE_ALL;
192/* Logging mode for current run */
193static enum log_mode_t host_log_mode;
194static pthread_t vcpu_thread;
195static uint32_t test_dirty_ring_count = TEST_DIRTY_RING_COUNT;
196
197static void vcpu_kick(void)
198{
199 pthread_kill(vcpu_thread, SIG_IPI);
200}
201
202/*
203 * In our test we do signal tricks, let's use a better version of
204 * sem_wait to avoid signal interrupts
205 */
206static void sem_wait_until(sem_t *sem)
207{
208 int ret;
209
210 do
211 ret = sem_wait(sem);
212 while (ret == -1 && errno == EINTR);
213}
214
215static bool clear_log_supported(void)
216{
217 return kvm_has_cap(KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2);
218}
219
220static void clear_log_create_vm_done(struct kvm_vm *vm)
221{
222 u64 manual_caps;
223
224 manual_caps = kvm_check_cap(KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2);
225 TEST_ASSERT(manual_caps, "MANUAL_CAPS is zero!");
226 manual_caps &= (KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE |
227 KVM_DIRTY_LOG_INITIALLY_SET);
228 vm_enable_cap(vm, KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2, manual_caps);
229}
230
231static void dirty_log_collect_dirty_pages(struct kvm_vcpu *vcpu, int slot,
232 void *bitmap, uint32_t num_pages,
233 uint32_t *unused)
234{
235 kvm_vm_get_dirty_log(vcpu->vm, slot, bitmap);
236}
237
238static void clear_log_collect_dirty_pages(struct kvm_vcpu *vcpu, int slot,
239 void *bitmap, uint32_t num_pages,
240 uint32_t *unused)
241{
242 kvm_vm_get_dirty_log(vcpu->vm, slot, bitmap);
243 kvm_vm_clear_dirty_log(vcpu->vm, slot, bitmap, 0, num_pages);
244}
245
246/* Should only be called after a GUEST_SYNC */
247static void vcpu_handle_sync_stop(void)
248{
249 if (atomic_read(v: &vcpu_sync_stop_requested)) {
250 /* It means main thread is sleeping waiting */
251 atomic_set(v: &vcpu_sync_stop_requested, i: false);
252 sem_post(&sem_vcpu_stop);
253 sem_wait_until(&sem_vcpu_cont);
254 }
255}
256
257static void default_after_vcpu_run(struct kvm_vcpu *vcpu, int ret, int err)
258{
259 struct kvm_run *run = vcpu->run;
260
261 TEST_ASSERT(ret == 0 || (ret == -1 && err == EINTR),
262 "vcpu run failed: errno=%d", err);
263
264 TEST_ASSERT(get_ucall(vcpu, NULL) == UCALL_SYNC,
265 "Invalid guest sync status: exit_reason=%s",
266 exit_reason_str(run->exit_reason));
267
268 vcpu_handle_sync_stop();
269}
270
271static bool dirty_ring_supported(void)
272{
273 return (kvm_has_cap(KVM_CAP_DIRTY_LOG_RING) ||
274 kvm_has_cap(KVM_CAP_DIRTY_LOG_RING_ACQ_REL));
275}
276
277static void dirty_ring_create_vm_done(struct kvm_vm *vm)
278{
279 uint64_t pages;
280 uint32_t limit;
281
282 /*
283 * We rely on vcpu exit due to full dirty ring state. Adjust
284 * the ring buffer size to ensure we're able to reach the
285 * full dirty ring state.
286 */
287 pages = (1ul << (DIRTY_MEM_BITS - vm->page_shift)) + 3;
288 pages = vm_adjust_num_guest_pages(vm->mode, pages);
289 if (vm->page_size < getpagesize())
290 pages = vm_num_host_pages(vm->mode, pages);
291
292 limit = 1 << (31 - __builtin_clz(pages));
293 test_dirty_ring_count = 1 << (31 - __builtin_clz(test_dirty_ring_count));
294 test_dirty_ring_count = min(limit, test_dirty_ring_count);
295 pr_info("dirty ring count: 0x%x\n", test_dirty_ring_count);
296
297 /*
298 * Switch to dirty ring mode after VM creation but before any
299 * of the vcpu creation.
300 */
301 vm_enable_dirty_ring(vm, test_dirty_ring_count *
302 sizeof(struct kvm_dirty_gfn));
303}
304
305static inline bool dirty_gfn_is_dirtied(struct kvm_dirty_gfn *gfn)
306{
307 return smp_load_acquire(&gfn->flags) == KVM_DIRTY_GFN_F_DIRTY;
308}
309
310static inline void dirty_gfn_set_collected(struct kvm_dirty_gfn *gfn)
311{
312 smp_store_release(&gfn->flags, KVM_DIRTY_GFN_F_RESET);
313}
314
315static uint32_t dirty_ring_collect_one(struct kvm_dirty_gfn *dirty_gfns,
316 int slot, void *bitmap,
317 uint32_t num_pages, uint32_t *fetch_index)
318{
319 struct kvm_dirty_gfn *cur;
320 uint32_t count = 0;
321
322 while (true) {
323 cur = &dirty_gfns[*fetch_index % test_dirty_ring_count];
324 if (!dirty_gfn_is_dirtied(gfn: cur))
325 break;
326 TEST_ASSERT(cur->slot == slot, "Slot number didn't match: "
327 "%u != %u", cur->slot, slot);
328 TEST_ASSERT(cur->offset < num_pages, "Offset overflow: "
329 "0x%llx >= 0x%x", cur->offset, num_pages);
330 //pr_info("fetch 0x%x page %llu\n", *fetch_index, cur->offset);
331 __set_bit_le(cur->offset, bitmap);
332 dirty_ring_last_page = cur->offset;
333 dirty_gfn_set_collected(gfn: cur);
334 (*fetch_index)++;
335 count++;
336 }
337
338 return count;
339}
340
341static void dirty_ring_wait_vcpu(void)
342{
343 /* This makes sure that hardware PML cache flushed */
344 vcpu_kick();
345 sem_wait_until(&sem_vcpu_stop);
346}
347
348static void dirty_ring_continue_vcpu(void)
349{
350 pr_info("Notifying vcpu to continue\n");
351 sem_post(&sem_vcpu_cont);
352}
353
354static void dirty_ring_collect_dirty_pages(struct kvm_vcpu *vcpu, int slot,
355 void *bitmap, uint32_t num_pages,
356 uint32_t *ring_buf_idx)
357{
358 uint32_t count = 0, cleared;
359 bool continued_vcpu = false;
360
361 dirty_ring_wait_vcpu();
362
363 if (!dirty_ring_vcpu_ring_full) {
364 /*
365 * This is not a ring-full event, it's safe to allow
366 * vcpu to continue
367 */
368 dirty_ring_continue_vcpu();
369 continued_vcpu = true;
370 }
371
372 /* Only have one vcpu */
373 count = dirty_ring_collect_one(dirty_gfns: vcpu_map_dirty_ring(vcpu),
374 slot, bitmap, num_pages,
375 fetch_index: ring_buf_idx);
376
377 cleared = kvm_vm_reset_dirty_ring(vcpu->vm);
378
379 /*
380 * Cleared pages should be the same as collected, as KVM is supposed to
381 * clear only the entries that have been harvested.
382 */
383 TEST_ASSERT(cleared == count, "Reset dirty pages (%u) mismatch "
384 "with collected (%u)", cleared, count);
385
386 if (!continued_vcpu) {
387 TEST_ASSERT(dirty_ring_vcpu_ring_full,
388 "Didn't continue vcpu even without ring full");
389 dirty_ring_continue_vcpu();
390 }
391
392 pr_info("Iteration %ld collected %u pages\n", iteration, count);
393}
394
395static void dirty_ring_after_vcpu_run(struct kvm_vcpu *vcpu, int ret, int err)
396{
397 struct kvm_run *run = vcpu->run;
398
399 /* A ucall-sync or ring-full event is allowed */
400 if (get_ucall(vcpu, NULL) == UCALL_SYNC) {
401 /* We should allow this to continue */
402 ;
403 } else if (run->exit_reason == KVM_EXIT_DIRTY_RING_FULL ||
404 (ret == -1 && err == EINTR)) {
405 /* Update the flag first before pause */
406 WRITE_ONCE(dirty_ring_vcpu_ring_full,
407 run->exit_reason == KVM_EXIT_DIRTY_RING_FULL);
408 sem_post(&sem_vcpu_stop);
409 pr_info("vcpu stops because %s...\n",
410 dirty_ring_vcpu_ring_full ?
411 "dirty ring is full" : "vcpu is kicked out");
412 sem_wait_until(&sem_vcpu_cont);
413 pr_info("vcpu continues now.\n");
414 } else {
415 TEST_ASSERT(false, "Invalid guest sync status: "
416 "exit_reason=%s",
417 exit_reason_str(run->exit_reason));
418 }
419}
420
421struct log_mode {
422 const char *name;
423 /* Return true if this mode is supported, otherwise false */
424 bool (*supported)(void);
425 /* Hook when the vm creation is done (before vcpu creation) */
426 void (*create_vm_done)(struct kvm_vm *vm);
427 /* Hook to collect the dirty pages into the bitmap provided */
428 void (*collect_dirty_pages) (struct kvm_vcpu *vcpu, int slot,
429 void *bitmap, uint32_t num_pages,
430 uint32_t *ring_buf_idx);
431 /* Hook to call when after each vcpu run */
432 void (*after_vcpu_run)(struct kvm_vcpu *vcpu, int ret, int err);
433} log_modes[LOG_MODE_NUM] = {
434 {
435 .name = "dirty-log",
436 .collect_dirty_pages = dirty_log_collect_dirty_pages,
437 .after_vcpu_run = default_after_vcpu_run,
438 },
439 {
440 .name = "clear-log",
441 .supported = clear_log_supported,
442 .create_vm_done = clear_log_create_vm_done,
443 .collect_dirty_pages = clear_log_collect_dirty_pages,
444 .after_vcpu_run = default_after_vcpu_run,
445 },
446 {
447 .name = "dirty-ring",
448 .supported = dirty_ring_supported,
449 .create_vm_done = dirty_ring_create_vm_done,
450 .collect_dirty_pages = dirty_ring_collect_dirty_pages,
451 .after_vcpu_run = dirty_ring_after_vcpu_run,
452 },
453};
454
455/*
456 * We use this bitmap to track some pages that should have its dirty
457 * bit set in the _next_ iteration. For example, if we detected the
458 * page value changed to current iteration but at the same time the
459 * page bit is cleared in the latest bitmap, then the system must
460 * report that write in the next get dirty log call.
461 */
462static unsigned long *host_bmap_track;
463
464static void log_modes_dump(void)
465{
466 int i;
467
468 printf("all");
469 for (i = 0; i < LOG_MODE_NUM; i++)
470 printf(", %s", log_modes[i].name);
471 printf("\n");
472}
473
474static bool log_mode_supported(void)
475{
476 struct log_mode *mode = &log_modes[host_log_mode];
477
478 if (mode->supported)
479 return mode->supported();
480
481 return true;
482}
483
484static void log_mode_create_vm_done(struct kvm_vm *vm)
485{
486 struct log_mode *mode = &log_modes[host_log_mode];
487
488 if (mode->create_vm_done)
489 mode->create_vm_done(vm);
490}
491
492static void log_mode_collect_dirty_pages(struct kvm_vcpu *vcpu, int slot,
493 void *bitmap, uint32_t num_pages,
494 uint32_t *ring_buf_idx)
495{
496 struct log_mode *mode = &log_modes[host_log_mode];
497
498 TEST_ASSERT(mode->collect_dirty_pages != NULL,
499 "collect_dirty_pages() is required for any log mode!");
500 mode->collect_dirty_pages(vcpu, slot, bitmap, num_pages, ring_buf_idx);
501}
502
503static void log_mode_after_vcpu_run(struct kvm_vcpu *vcpu, int ret, int err)
504{
505 struct log_mode *mode = &log_modes[host_log_mode];
506
507 if (mode->after_vcpu_run)
508 mode->after_vcpu_run(vcpu, ret, err);
509}
510
511static void generate_random_array(uint64_t *guest_array, uint64_t size)
512{
513 uint64_t i;
514
515 for (i = 0; i < size; i++)
516 guest_array[i] = random();
517}
518
519static void *vcpu_worker(void *data)
520{
521 int ret;
522 struct kvm_vcpu *vcpu = data;
523 struct kvm_vm *vm = vcpu->vm;
524 uint64_t *guest_array;
525 uint64_t pages_count = 0;
526 struct kvm_signal_mask *sigmask = alloca(offsetof(struct kvm_signal_mask, sigset)
527 + sizeof(sigset_t));
528 sigset_t *sigset = (sigset_t *) &sigmask->sigset;
529
530 /*
531 * SIG_IPI is unblocked atomically while in KVM_RUN. It causes the
532 * ioctl to return with -EINTR, but it is still pending and we need
533 * to accept it with the sigwait.
534 */
535 sigmask->len = 8;
536 pthread_sigmask(0, NULL, sigset);
537 sigdelset(sigset, SIG_IPI);
538 vcpu_ioctl(vcpu, KVM_SET_SIGNAL_MASK, sigmask);
539
540 sigemptyset(sigset);
541 sigaddset(sigset, SIG_IPI);
542
543 guest_array = addr_gva2hva(vm, (vm_vaddr_t)random_array);
544
545 while (!READ_ONCE(host_quit)) {
546 /* Clear any existing kick signals */
547 generate_random_array(guest_array, TEST_PAGES_PER_LOOP);
548 pages_count += TEST_PAGES_PER_LOOP;
549 /* Let the guest dirty the random pages */
550 ret = __vcpu_run(vcpu);
551 if (ret == -1 && errno == EINTR) {
552 int sig = -1;
553 sigwait(sigset, &sig);
554 assert(sig == SIG_IPI);
555 }
556 log_mode_after_vcpu_run(vcpu, ret, errno);
557 }
558
559 pr_info("Dirtied %"PRIu64" pages\n", pages_count);
560
561 return NULL;
562}
563
564static void vm_dirty_log_verify(enum vm_guest_mode mode, unsigned long *bmap)
565{
566 uint64_t step = vm_num_host_pages(mode, 1);
567 uint64_t page;
568 uint64_t *value_ptr;
569 uint64_t min_iter = 0;
570
571 for (page = 0; page < host_num_pages; page += step) {
572 value_ptr = host_test_mem + page * host_page_size;
573
574 /* If this is a special page that we were tracking... */
575 if (__test_and_clear_bit_le(page, host_bmap_track)) {
576 host_track_next_count++;
577 TEST_ASSERT(test_bit_le(page, bmap),
578 "Page %"PRIu64" should have its dirty bit "
579 "set in this iteration but it is missing",
580 page);
581 }
582
583 if (__test_and_clear_bit_le(page, bmap)) {
584 bool matched;
585
586 host_dirty_count++;
587
588 /*
589 * If the bit is set, the value written onto
590 * the corresponding page should be either the
591 * previous iteration number or the current one.
592 */
593 matched = (*value_ptr == iteration ||
594 *value_ptr == iteration - 1);
595
596 if (host_log_mode == LOG_MODE_DIRTY_RING && !matched) {
597 if (*value_ptr == iteration - 2 && min_iter <= iteration - 2) {
598 /*
599 * Short answer: this case is special
600 * only for dirty ring test where the
601 * page is the last page before a kvm
602 * dirty ring full in iteration N-2.
603 *
604 * Long answer: Assuming ring size R,
605 * one possible condition is:
606 *
607 * main thr vcpu thr
608 * -------- --------
609 * iter=1
610 * write 1 to page 0~(R-1)
611 * full, vmexit
612 * collect 0~(R-1)
613 * kick vcpu
614 * write 1 to (R-1)~(2R-2)
615 * full, vmexit
616 * iter=2
617 * collect (R-1)~(2R-2)
618 * kick vcpu
619 * write 1 to (2R-2)
620 * (NOTE!!! "1" cached in cpu reg)
621 * write 2 to (2R-1)~(3R-3)
622 * full, vmexit
623 * iter=3
624 * collect (2R-2)~(3R-3)
625 * (here if we read value on page
626 * "2R-2" is 1, while iter=3!!!)
627 *
628 * This however can only happen once per iteration.
629 */
630 min_iter = iteration - 1;
631 continue;
632 } else if (page == dirty_ring_last_page) {
633 /*
634 * Please refer to comments in
635 * dirty_ring_last_page.
636 */
637 continue;
638 }
639 }
640
641 TEST_ASSERT(matched,
642 "Set page %"PRIu64" value %"PRIu64
643 " incorrect (iteration=%"PRIu64")",
644 page, *value_ptr, iteration);
645 } else {
646 host_clear_count++;
647 /*
648 * If cleared, the value written can be any
649 * value smaller or equals to the iteration
650 * number. Note that the value can be exactly
651 * (iteration-1) if that write can happen
652 * like this:
653 *
654 * (1) increase loop count to "iteration-1"
655 * (2) write to page P happens (with value
656 * "iteration-1")
657 * (3) get dirty log for "iteration-1"; we'll
658 * see that page P bit is set (dirtied),
659 * and not set the bit in host_bmap_track
660 * (4) increase loop count to "iteration"
661 * (which is current iteration)
662 * (5) get dirty log for current iteration,
663 * we'll see that page P is cleared, with
664 * value "iteration-1".
665 */
666 TEST_ASSERT(*value_ptr <= iteration,
667 "Clear page %"PRIu64" value %"PRIu64
668 " incorrect (iteration=%"PRIu64")",
669 page, *value_ptr, iteration);
670 if (*value_ptr == iteration) {
671 /*
672 * This page is _just_ modified; it
673 * should report its dirtyness in the
674 * next run
675 */
676 __set_bit_le(page, host_bmap_track);
677 }
678 }
679 }
680}
681
682static struct kvm_vm *create_vm(enum vm_guest_mode mode, struct kvm_vcpu **vcpu,
683 uint64_t extra_mem_pages, void *guest_code)
684{
685 struct kvm_vm *vm;
686
687 pr_info("Testing guest mode: %s\n", vm_guest_mode_string(mode));
688
689 vm = __vm_create(VM_SHAPE(mode), 1, extra_mem_pages);
690
691 log_mode_create_vm_done(vm);
692 *vcpu = vm_vcpu_add(vm, 0, guest_code);
693 return vm;
694}
695
696struct test_params {
697 unsigned long iterations;
698 unsigned long interval;
699 uint64_t phys_offset;
700};
701
702static void run_test(enum vm_guest_mode mode, void *arg)
703{
704 struct test_params *p = arg;
705 struct kvm_vcpu *vcpu;
706 struct kvm_vm *vm;
707 unsigned long *bmap;
708 uint32_t ring_buf_idx = 0;
709 int sem_val;
710
711 if (!log_mode_supported()) {
712 print_skip("Log mode '%s' not supported",
713 log_modes[host_log_mode].name);
714 return;
715 }
716
717 /*
718 * We reserve page table for 2 times of extra dirty mem which
719 * will definitely cover the original (1G+) test range. Here
720 * we do the calculation with 4K page size which is the
721 * smallest so the page number will be enough for all archs
722 * (e.g., 64K page size guest will need even less memory for
723 * page tables).
724 */
725 vm = create_vm(mode: mode, vcpu: &vcpu,
726 extra_mem_pages: 2ul << (DIRTY_MEM_BITS - PAGE_SHIFT_4K), guest_code);
727
728 guest_page_size = vm->page_size;
729 /*
730 * A little more than 1G of guest page sized pages. Cover the
731 * case where the size is not aligned to 64 pages.
732 */
733 guest_num_pages = (1ul << (DIRTY_MEM_BITS - vm->page_shift)) + 3;
734 guest_num_pages = vm_adjust_num_guest_pages(mode, guest_num_pages);
735
736 host_page_size = getpagesize();
737 host_num_pages = vm_num_host_pages(mode, guest_num_pages);
738
739 if (!p->phys_offset) {
740 guest_test_phys_mem = (vm->max_gfn - guest_num_pages) *
741 guest_page_size;
742 guest_test_phys_mem = align_down(guest_test_phys_mem, host_page_size);
743 } else {
744 guest_test_phys_mem = p->phys_offset;
745 }
746
747#ifdef __s390x__
748 /* Align to 1M (segment size) */
749 guest_test_phys_mem = align_down(guest_test_phys_mem, 1 << 20);
750#endif
751
752 pr_info("guest physical test memory offset: 0x%lx\n", guest_test_phys_mem);
753
754 bmap = bitmap_zalloc(host_num_pages);
755 host_bmap_track = bitmap_zalloc(host_num_pages);
756
757 /* Add an extra memory slot for testing dirty logging */
758 vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS,
759 guest_test_phys_mem,
760 TEST_MEM_SLOT_INDEX,
761 guest_num_pages,
762 KVM_MEM_LOG_DIRTY_PAGES);
763
764 /* Do mapping for the dirty track memory slot */
765 virt_map(vm, guest_test_virt_mem, guest_test_phys_mem, guest_num_pages);
766
767 /* Cache the HVA pointer of the region */
768 host_test_mem = addr_gpa2hva(vm, (vm_paddr_t)guest_test_phys_mem);
769
770 /* Export the shared variables to the guest */
771 sync_global_to_guest(vm, host_page_size);
772 sync_global_to_guest(vm, guest_page_size);
773 sync_global_to_guest(vm, guest_test_virt_mem);
774 sync_global_to_guest(vm, guest_num_pages);
775
776 /* Start the iterations */
777 iteration = 1;
778 sync_global_to_guest(vm, iteration);
779 WRITE_ONCE(host_quit, false);
780 host_dirty_count = 0;
781 host_clear_count = 0;
782 host_track_next_count = 0;
783 WRITE_ONCE(dirty_ring_vcpu_ring_full, false);
784
785 /*
786 * Ensure the previous iteration didn't leave a dangling semaphore, i.e.
787 * that the main task and vCPU worker were synchronized and completed
788 * verification of all iterations.
789 */
790 sem_getvalue(&sem_vcpu_stop, &sem_val);
791 TEST_ASSERT_EQ(sem_val, 0);
792 sem_getvalue(&sem_vcpu_cont, &sem_val);
793 TEST_ASSERT_EQ(sem_val, 0);
794
795 pthread_create(&vcpu_thread, NULL, vcpu_worker, vcpu);
796
797 while (iteration < p->iterations) {
798 /* Give the vcpu thread some time to dirty some pages */
799 usleep(p->interval * 1000);
800 log_mode_collect_dirty_pages(vcpu, TEST_MEM_SLOT_INDEX,
801 bitmap: bmap, num_pages: host_num_pages,
802 ring_buf_idx: &ring_buf_idx);
803
804 /*
805 * See vcpu_sync_stop_requested definition for details on why
806 * we need to stop vcpu when verify data.
807 */
808 atomic_set(v: &vcpu_sync_stop_requested, i: true);
809 sem_wait_until(&sem_vcpu_stop);
810 /*
811 * NOTE: for dirty ring, it's possible that we didn't stop at
812 * GUEST_SYNC but instead we stopped because ring is full;
813 * that's okay too because ring full means we're only missing
814 * the flush of the last page, and since we handle the last
815 * page specially verification will succeed anyway.
816 */
817 assert(host_log_mode == LOG_MODE_DIRTY_RING ||
818 atomic_read(v: &vcpu_sync_stop_requested) == false);
819 vm_dirty_log_verify(mode: mode, bmap);
820
821 /*
822 * Set host_quit before sem_vcpu_cont in the final iteration to
823 * ensure that the vCPU worker doesn't resume the guest. As
824 * above, the dirty ring test may stop and wait even when not
825 * explicitly request to do so, i.e. would hang waiting for a
826 * "continue" if it's allowed to resume the guest.
827 */
828 if (++iteration == p->iterations)
829 WRITE_ONCE(host_quit, true);
830
831 sem_post(&sem_vcpu_cont);
832 sync_global_to_guest(vm, iteration);
833 }
834
835 pthread_join(vcpu_thread, NULL);
836
837 pr_info("Total bits checked: dirty (%"PRIu64"), clear (%"PRIu64"), "
838 "track_next (%"PRIu64")\n", host_dirty_count, host_clear_count,
839 host_track_next_count);
840
841 free(bmap);
842 free(host_bmap_track);
843 kvm_vm_free(vm);
844}
845
846static void help(char *name)
847{
848 puts("");
849 printf("usage: %s [-h] [-i iterations] [-I interval] "
850 "[-p offset] [-m mode]\n", name);
851 puts("");
852 printf(" -c: hint to dirty ring size, in number of entries\n");
853 printf(" (only useful for dirty-ring test; default: %"PRIu32")\n",
854 TEST_DIRTY_RING_COUNT);
855 printf(" -i: specify iteration counts (default: %"PRIu64")\n",
856 TEST_HOST_LOOP_N);
857 printf(" -I: specify interval in ms (default: %"PRIu64" ms)\n",
858 TEST_HOST_LOOP_INTERVAL);
859 printf(" -p: specify guest physical test memory offset\n"
860 " Warning: a low offset can conflict with the loaded test code.\n");
861 printf(" -M: specify the host logging mode "
862 "(default: run all log modes). Supported modes: \n\t");
863 log_modes_dump();
864 guest_modes_help();
865 puts("");
866 exit(0);
867}
868
869int main(int argc, char *argv[])
870{
871 struct test_params p = {
872 .iterations = TEST_HOST_LOOP_N,
873 .interval = TEST_HOST_LOOP_INTERVAL,
874 };
875 int opt, i;
876 sigset_t sigset;
877
878 sem_init(&sem_vcpu_stop, 0, 0);
879 sem_init(&sem_vcpu_cont, 0, 0);
880
881 guest_modes_append_default();
882
883 while ((opt = getopt(argc, argv, "c:hi:I:p:m:M:")) != -1) {
884 switch (opt) {
885 case 'c':
886 test_dirty_ring_count = strtol(optarg, NULL, 10);
887 break;
888 case 'i':
889 p.iterations = strtol(optarg, NULL, 10);
890 break;
891 case 'I':
892 p.interval = strtol(optarg, NULL, 10);
893 break;
894 case 'p':
895 p.phys_offset = strtoull(optarg, NULL, 0);
896 break;
897 case 'm':
898 guest_modes_cmdline(optarg);
899 break;
900 case 'M':
901 if (!strcmp(optarg, "all")) {
902 host_log_mode_option = LOG_MODE_ALL;
903 break;
904 }
905 for (i = 0; i < LOG_MODE_NUM; i++) {
906 if (!strcmp(optarg, log_modes[i].name)) {
907 pr_info("Setting log mode to: '%s'\n",
908 optarg);
909 host_log_mode_option = i;
910 break;
911 }
912 }
913 if (i == LOG_MODE_NUM) {
914 printf("Log mode '%s' invalid. Please choose "
915 "from: ", optarg);
916 log_modes_dump();
917 exit(1);
918 }
919 break;
920 case 'h':
921 default:
922 help(name: argv[0]);
923 break;
924 }
925 }
926
927 TEST_ASSERT(p.iterations > 2, "Iterations must be greater than two");
928 TEST_ASSERT(p.interval > 0, "Interval must be greater than zero");
929
930 pr_info("Test iterations: %"PRIu64", interval: %"PRIu64" (ms)\n",
931 p.iterations, p.interval);
932
933 srandom(time(0));
934
935 /* Ensure that vCPU threads start with SIG_IPI blocked. */
936 sigemptyset(&sigset);
937 sigaddset(&sigset, SIG_IPI);
938 pthread_sigmask(SIG_BLOCK, &sigset, NULL);
939
940 if (host_log_mode_option == LOG_MODE_ALL) {
941 /* Run each log mode */
942 for (i = 0; i < LOG_MODE_NUM; i++) {
943 pr_info("Testing Log Mode '%s'\n", log_modes[i].name);
944 host_log_mode = i;
945 for_each_guest_mode(run_test, &p);
946 }
947 } else {
948 host_log_mode = host_log_mode_option;
949 for_each_guest_mode(run_test, &p);
950 }
951
952 return 0;
953}
954

source code of linux/tools/testing/selftests/kvm/dirty_log_test.c