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 #include <stdio.h>
9 #include <stdlib.h>
10 #include <unistd.h>
11 #include <time.h>
12 #include <pthread.h>
13 #include <linux/bitmap.h>
14 #include <linux/bitops.h>
15
16 #include "test_util.h"
17 #include "kvm_util.h"
18
19 #define DEBUG printf
20
21 #define VCPU_ID 1
22 /* The memory slot index to track dirty pages */
23 #define TEST_MEM_SLOT_INDEX 1
24 /*
25 * GPA offset of the testing memory slot. Must be bigger than the
26 * default vm mem slot, which is DEFAULT_GUEST_PHY_PAGES.
27 */
28 #define TEST_MEM_OFFSET (1ULL << 30) /* 1G */
29 /* Size of the testing memory slot */
30 #define TEST_MEM_PAGES (1ULL << 18) /* 1G for 4K pages */
31 /* How many pages to dirty for each guest loop */
32 #define TEST_PAGES_PER_LOOP 1024
33 /* How many host loops to run (one KVM_GET_DIRTY_LOG for each loop) */
34 #define TEST_HOST_LOOP_N 32
35 /* Interval for each host loop (ms) */
36 #define TEST_HOST_LOOP_INTERVAL 10
37
38 /*
39 * Guest variables. We use these variables to share data between host
40 * and guest. There are two copies of the variables, one in host memory
41 * (which is unused) and one in guest memory. When the host wants to
42 * access these variables, it needs to call addr_gva2hva() to access the
43 * guest copy.
44 */
45 uint64_t guest_random_array[TEST_PAGES_PER_LOOP];
46 uint64_t guest_iteration;
47 uint64_t guest_page_size;
48
49 /*
50 * Writes to the first byte of a random page within the testing memory
51 * region continuously.
52 */
guest_code(void)53 void guest_code(void)
54 {
55 int i = 0;
56 uint64_t volatile *array = guest_random_array;
57 uint64_t volatile *guest_addr;
58
59 while (true) {
60 for (i = 0; i < TEST_PAGES_PER_LOOP; i++) {
61 /*
62 * Write to the first 8 bytes of a random page
63 * on the testing memory region.
64 */
65 guest_addr = (uint64_t *)
66 (TEST_MEM_OFFSET +
67 (array[i] % TEST_MEM_PAGES) * guest_page_size);
68 *guest_addr = guest_iteration;
69 }
70 /* Tell the host that we need more random numbers */
71 GUEST_SYNC(1);
72 }
73 }
74
75 /*
76 * Host variables. These variables should only be used by the host
77 * rather than the guest.
78 */
79 bool host_quit;
80
81 /* Points to the test VM memory region on which we track dirty logs */
82 void *host_test_mem;
83
84 /* For statistics only */
85 uint64_t host_dirty_count;
86 uint64_t host_clear_count;
87 uint64_t host_track_next_count;
88
89 /*
90 * We use this bitmap to track some pages that should have its dirty
91 * bit set in the _next_ iteration. For example, if we detected the
92 * page value changed to current iteration but at the same time the
93 * page bit is cleared in the latest bitmap, then the system must
94 * report that write in the next get dirty log call.
95 */
96 unsigned long *host_bmap_track;
97
generate_random_array(uint64_t * guest_array,uint64_t size)98 void generate_random_array(uint64_t *guest_array, uint64_t size)
99 {
100 uint64_t i;
101
102 for (i = 0; i < size; i++) {
103 guest_array[i] = random();
104 }
105 }
106
vcpu_worker(void * data)107 void *vcpu_worker(void *data)
108 {
109 int ret;
110 uint64_t loops, *guest_array, pages_count = 0;
111 struct kvm_vm *vm = data;
112 struct kvm_run *run;
113 struct guest_args args;
114
115 run = vcpu_state(vm, VCPU_ID);
116
117 /* Retrieve the guest random array pointer and cache it */
118 guest_array = addr_gva2hva(vm, (vm_vaddr_t)guest_random_array);
119
120 DEBUG("VCPU starts\n");
121
122 generate_random_array(guest_array, TEST_PAGES_PER_LOOP);
123
124 while (!READ_ONCE(host_quit)) {
125 /* Let the guest to dirty these random pages */
126 ret = _vcpu_run(vm, VCPU_ID);
127 guest_args_read(vm, VCPU_ID, &args);
128 if (run->exit_reason == KVM_EXIT_IO &&
129 args.port == GUEST_PORT_SYNC) {
130 pages_count += TEST_PAGES_PER_LOOP;
131 generate_random_array(guest_array, TEST_PAGES_PER_LOOP);
132 } else {
133 TEST_ASSERT(false,
134 "Invalid guest sync status: "
135 "exit_reason=%s\n",
136 exit_reason_str(run->exit_reason));
137 }
138 }
139
140 DEBUG("VCPU exits, dirtied %"PRIu64" pages\n", pages_count);
141
142 return NULL;
143 }
144
vm_dirty_log_verify(unsigned long * bmap,uint64_t iteration)145 void vm_dirty_log_verify(unsigned long *bmap, uint64_t iteration)
146 {
147 uint64_t page;
148 uint64_t volatile *value_ptr;
149
150 for (page = 0; page < TEST_MEM_PAGES; page++) {
151 value_ptr = host_test_mem + page * getpagesize();
152
153 /* If this is a special page that we were tracking... */
154 if (test_and_clear_bit(page, host_bmap_track)) {
155 host_track_next_count++;
156 TEST_ASSERT(test_bit(page, bmap),
157 "Page %"PRIu64" should have its dirty bit "
158 "set in this iteration but it is missing",
159 page);
160 }
161
162 if (test_bit(page, bmap)) {
163 host_dirty_count++;
164 /*
165 * If the bit is set, the value written onto
166 * the corresponding page should be either the
167 * previous iteration number or the current one.
168 */
169 TEST_ASSERT(*value_ptr == iteration ||
170 *value_ptr == iteration - 1,
171 "Set page %"PRIu64" value %"PRIu64
172 " incorrect (iteration=%"PRIu64")",
173 page, *value_ptr, iteration);
174 } else {
175 host_clear_count++;
176 /*
177 * If cleared, the value written can be any
178 * value smaller or equals to the iteration
179 * number. Note that the value can be exactly
180 * (iteration-1) if that write can happen
181 * like this:
182 *
183 * (1) increase loop count to "iteration-1"
184 * (2) write to page P happens (with value
185 * "iteration-1")
186 * (3) get dirty log for "iteration-1"; we'll
187 * see that page P bit is set (dirtied),
188 * and not set the bit in host_bmap_track
189 * (4) increase loop count to "iteration"
190 * (which is current iteration)
191 * (5) get dirty log for current iteration,
192 * we'll see that page P is cleared, with
193 * value "iteration-1".
194 */
195 TEST_ASSERT(*value_ptr <= iteration,
196 "Clear page %"PRIu64" value %"PRIu64
197 " incorrect (iteration=%"PRIu64")",
198 page, *value_ptr, iteration);
199 if (*value_ptr == iteration) {
200 /*
201 * This page is _just_ modified; it
202 * should report its dirtyness in the
203 * next run
204 */
205 set_bit(page, host_bmap_track);
206 }
207 }
208 }
209 }
210
help(char * name)211 void help(char *name)
212 {
213 puts("");
214 printf("usage: %s [-i iterations] [-I interval] [-h]\n", name);
215 puts("");
216 printf(" -i: specify iteration counts (default: %"PRIu64")\n",
217 TEST_HOST_LOOP_N);
218 printf(" -I: specify interval in ms (default: %"PRIu64" ms)\n",
219 TEST_HOST_LOOP_INTERVAL);
220 puts("");
221 exit(0);
222 }
223
main(int argc,char * argv[])224 int main(int argc, char *argv[])
225 {
226 pthread_t vcpu_thread;
227 struct kvm_vm *vm;
228 uint64_t volatile *psize, *iteration;
229 unsigned long *bmap, iterations = TEST_HOST_LOOP_N,
230 interval = TEST_HOST_LOOP_INTERVAL;
231 int opt;
232
233 while ((opt = getopt(argc, argv, "hi:I:")) != -1) {
234 switch (opt) {
235 case 'i':
236 iterations = strtol(optarg, NULL, 10);
237 break;
238 case 'I':
239 interval = strtol(optarg, NULL, 10);
240 break;
241 case 'h':
242 default:
243 help(argv[0]);
244 break;
245 }
246 }
247
248 TEST_ASSERT(iterations > 2, "Iteration must be bigger than zero\n");
249 TEST_ASSERT(interval > 0, "Interval must be bigger than zero");
250
251 DEBUG("Test iterations: %"PRIu64", interval: %"PRIu64" (ms)\n",
252 iterations, interval);
253
254 srandom(time(0));
255
256 bmap = bitmap_alloc(TEST_MEM_PAGES);
257 host_bmap_track = bitmap_alloc(TEST_MEM_PAGES);
258
259 vm = vm_create_default(VCPU_ID, TEST_MEM_PAGES, guest_code);
260
261 /* Add an extra memory slot for testing dirty logging */
262 vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS,
263 TEST_MEM_OFFSET,
264 TEST_MEM_SLOT_INDEX,
265 TEST_MEM_PAGES,
266 KVM_MEM_LOG_DIRTY_PAGES);
267 /* Cache the HVA pointer of the region */
268 host_test_mem = addr_gpa2hva(vm, (vm_paddr_t)TEST_MEM_OFFSET);
269
270 /* Do 1:1 mapping for the dirty track memory slot */
271 virt_map(vm, TEST_MEM_OFFSET, TEST_MEM_OFFSET,
272 TEST_MEM_PAGES * getpagesize(), 0);
273
274 vcpu_set_cpuid(vm, VCPU_ID, kvm_get_supported_cpuid());
275
276 /* Tell the guest about the page size on the system */
277 psize = addr_gva2hva(vm, (vm_vaddr_t)&guest_page_size);
278 *psize = getpagesize();
279
280 /* Start the iterations */
281 iteration = addr_gva2hva(vm, (vm_vaddr_t)&guest_iteration);
282 *iteration = 1;
283
284 /* Start dirtying pages */
285 pthread_create(&vcpu_thread, NULL, vcpu_worker, vm);
286
287 while (*iteration < iterations) {
288 /* Give the vcpu thread some time to dirty some pages */
289 usleep(interval * 1000);
290 kvm_vm_get_dirty_log(vm, TEST_MEM_SLOT_INDEX, bmap);
291 vm_dirty_log_verify(bmap, *iteration);
292 (*iteration)++;
293 }
294
295 /* Tell the vcpu thread to quit */
296 host_quit = true;
297 pthread_join(vcpu_thread, NULL);
298
299 DEBUG("Total bits checked: dirty (%"PRIu64"), clear (%"PRIu64"), "
300 "track_next (%"PRIu64")\n", host_dirty_count, host_clear_count,
301 host_track_next_count);
302
303 free(bmap);
304 free(host_bmap_track);
305 kvm_vm_free(vm);
306
307 return 0;
308 }
309
