1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * KVM dirty page logging performance test
4  *
5  * Based on dirty_log_test.c
6  *
7  * Copyright (C) 2018, Red Hat, Inc.
8  * Copyright (C) 2020, Google, Inc.
9  */
10 
11 #include <stdio.h>
12 #include <stdlib.h>
13 #include <time.h>
14 #include <pthread.h>
15 #include <linux/bitmap.h>
16 
17 #include "kvm_util.h"
18 #include "test_util.h"
19 #include "memstress.h"
20 #include "guest_modes.h"
21 
22 #ifdef __aarch64__
23 #include "aarch64/vgic.h"
24 
25 #define GICD_BASE_GPA			0x8000000ULL
26 #define GICR_BASE_GPA			0x80A0000ULL
27 
28 static int gic_fd;
29 
arch_setup_vm(struct kvm_vm * vm,unsigned int nr_vcpus)30 static void arch_setup_vm(struct kvm_vm *vm, unsigned int nr_vcpus)
31 {
32 	/*
33 	 * The test can still run even if hardware does not support GICv3, as it
34 	 * is only an optimization to reduce guest exits.
35 	 */
36 	gic_fd = vgic_v3_setup(vm, nr_vcpus, 64, GICD_BASE_GPA, GICR_BASE_GPA);
37 }
38 
arch_cleanup_vm(struct kvm_vm * vm)39 static void arch_cleanup_vm(struct kvm_vm *vm)
40 {
41 	if (gic_fd > 0)
42 		close(gic_fd);
43 }
44 
45 #else /* __aarch64__ */
46 
arch_setup_vm(struct kvm_vm * vm,unsigned int nr_vcpus)47 static void arch_setup_vm(struct kvm_vm *vm, unsigned int nr_vcpus)
48 {
49 }
50 
arch_cleanup_vm(struct kvm_vm * vm)51 static void arch_cleanup_vm(struct kvm_vm *vm)
52 {
53 }
54 
55 #endif
56 
57 /* How many host loops to run by default (one KVM_GET_DIRTY_LOG for each loop)*/
58 #define TEST_HOST_LOOP_N		2UL
59 
60 static int nr_vcpus = 1;
61 static uint64_t guest_percpu_mem_size = DEFAULT_PER_VCPU_MEM_SIZE;
62 static bool run_vcpus_while_disabling_dirty_logging;
63 
64 /* Host variables */
65 static u64 dirty_log_manual_caps;
66 static bool host_quit;
67 static int iteration;
68 static int vcpu_last_completed_iteration[KVM_MAX_VCPUS];
69 
vcpu_worker(struct memstress_vcpu_args * vcpu_args)70 static void vcpu_worker(struct memstress_vcpu_args *vcpu_args)
71 {
72 	struct kvm_vcpu *vcpu = vcpu_args->vcpu;
73 	int vcpu_idx = vcpu_args->vcpu_idx;
74 	uint64_t pages_count = 0;
75 	struct kvm_run *run;
76 	struct timespec start;
77 	struct timespec ts_diff;
78 	struct timespec total = (struct timespec){0};
79 	struct timespec avg;
80 	int ret;
81 
82 	run = vcpu->run;
83 
84 	while (!READ_ONCE(host_quit)) {
85 		int current_iteration = READ_ONCE(iteration);
86 
87 		clock_gettime(CLOCK_MONOTONIC, &start);
88 		ret = _vcpu_run(vcpu);
89 		ts_diff = timespec_elapsed(start);
90 
91 		TEST_ASSERT(ret == 0, "vcpu_run failed: %d\n", ret);
92 		TEST_ASSERT(get_ucall(vcpu, NULL) == UCALL_SYNC,
93 			    "Invalid guest sync status: exit_reason=%s\n",
94 			    exit_reason_str(run->exit_reason));
95 
96 		pr_debug("Got sync event from vCPU %d\n", vcpu_idx);
97 		vcpu_last_completed_iteration[vcpu_idx] = current_iteration;
98 		pr_debug("vCPU %d updated last completed iteration to %d\n",
99 			 vcpu_idx, vcpu_last_completed_iteration[vcpu_idx]);
100 
101 		if (current_iteration) {
102 			pages_count += vcpu_args->pages;
103 			total = timespec_add(total, ts_diff);
104 			pr_debug("vCPU %d iteration %d dirty memory time: %ld.%.9lds\n",
105 				vcpu_idx, current_iteration, ts_diff.tv_sec,
106 				ts_diff.tv_nsec);
107 		} else {
108 			pr_debug("vCPU %d iteration %d populate memory time: %ld.%.9lds\n",
109 				vcpu_idx, current_iteration, ts_diff.tv_sec,
110 				ts_diff.tv_nsec);
111 		}
112 
113 		/*
114 		 * Keep running the guest while dirty logging is being disabled
115 		 * (iteration is negative) so that vCPUs are accessing memory
116 		 * for the entire duration of zapping collapsible SPTEs.
117 		 */
118 		while (current_iteration == READ_ONCE(iteration) &&
119 		       READ_ONCE(iteration) >= 0 && !READ_ONCE(host_quit)) {}
120 	}
121 
122 	avg = timespec_div(total, vcpu_last_completed_iteration[vcpu_idx]);
123 	pr_debug("\nvCPU %d dirtied 0x%lx pages over %d iterations in %ld.%.9lds. (Avg %ld.%.9lds/iteration)\n",
124 		vcpu_idx, pages_count, vcpu_last_completed_iteration[vcpu_idx],
125 		total.tv_sec, total.tv_nsec, avg.tv_sec, avg.tv_nsec);
126 }
127 
128 struct test_params {
129 	unsigned long iterations;
130 	uint64_t phys_offset;
131 	bool partition_vcpu_memory_access;
132 	enum vm_mem_backing_src_type backing_src;
133 	int slots;
134 	uint32_t write_percent;
135 	uint32_t random_seed;
136 	bool random_access;
137 };
138 
run_test(enum vm_guest_mode mode,void * arg)139 static void run_test(enum vm_guest_mode mode, void *arg)
140 {
141 	struct test_params *p = arg;
142 	struct kvm_vm *vm;
143 	unsigned long **bitmaps;
144 	uint64_t guest_num_pages;
145 	uint64_t host_num_pages;
146 	uint64_t pages_per_slot;
147 	struct timespec start;
148 	struct timespec ts_diff;
149 	struct timespec get_dirty_log_total = (struct timespec){0};
150 	struct timespec vcpu_dirty_total = (struct timespec){0};
151 	struct timespec avg;
152 	struct timespec clear_dirty_log_total = (struct timespec){0};
153 	int i;
154 
155 	vm = memstress_create_vm(mode, nr_vcpus, guest_percpu_mem_size,
156 				 p->slots, p->backing_src,
157 				 p->partition_vcpu_memory_access);
158 
159 	pr_info("Random seed: %u\n", p->random_seed);
160 	memstress_set_random_seed(vm, p->random_seed);
161 	memstress_set_write_percent(vm, p->write_percent);
162 
163 	guest_num_pages = (nr_vcpus * guest_percpu_mem_size) >> vm->page_shift;
164 	guest_num_pages = vm_adjust_num_guest_pages(mode, guest_num_pages);
165 	host_num_pages = vm_num_host_pages(mode, guest_num_pages);
166 	pages_per_slot = host_num_pages / p->slots;
167 
168 	bitmaps = memstress_alloc_bitmaps(p->slots, pages_per_slot);
169 
170 	if (dirty_log_manual_caps)
171 		vm_enable_cap(vm, KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2,
172 			      dirty_log_manual_caps);
173 
174 	arch_setup_vm(vm, nr_vcpus);
175 
176 	/* Start the iterations */
177 	iteration = 0;
178 	host_quit = false;
179 
180 	clock_gettime(CLOCK_MONOTONIC, &start);
181 	for (i = 0; i < nr_vcpus; i++)
182 		vcpu_last_completed_iteration[i] = -1;
183 
184 	/*
185 	 * Use 100% writes during the population phase to ensure all
186 	 * memory is actually populated and not just mapped to the zero
187 	 * page. The prevents expensive copy-on-write faults from
188 	 * occurring during the dirty memory iterations below, which
189 	 * would pollute the performance results.
190 	 */
191 	memstress_set_write_percent(vm, 100);
192 	memstress_set_random_access(vm, false);
193 	memstress_start_vcpu_threads(nr_vcpus, vcpu_worker);
194 
195 	/* Allow the vCPUs to populate memory */
196 	pr_debug("Starting iteration %d - Populating\n", iteration);
197 	for (i = 0; i < nr_vcpus; i++) {
198 		while (READ_ONCE(vcpu_last_completed_iteration[i]) !=
199 		       iteration)
200 			;
201 	}
202 
203 	ts_diff = timespec_elapsed(start);
204 	pr_info("Populate memory time: %ld.%.9lds\n",
205 		ts_diff.tv_sec, ts_diff.tv_nsec);
206 
207 	/* Enable dirty logging */
208 	clock_gettime(CLOCK_MONOTONIC, &start);
209 	memstress_enable_dirty_logging(vm, p->slots);
210 	ts_diff = timespec_elapsed(start);
211 	pr_info("Enabling dirty logging time: %ld.%.9lds\n\n",
212 		ts_diff.tv_sec, ts_diff.tv_nsec);
213 
214 	memstress_set_write_percent(vm, p->write_percent);
215 	memstress_set_random_access(vm, p->random_access);
216 
217 	while (iteration < p->iterations) {
218 		/*
219 		 * Incrementing the iteration number will start the vCPUs
220 		 * dirtying memory again.
221 		 */
222 		clock_gettime(CLOCK_MONOTONIC, &start);
223 		iteration++;
224 
225 		pr_debug("Starting iteration %d\n", iteration);
226 		for (i = 0; i < nr_vcpus; i++) {
227 			while (READ_ONCE(vcpu_last_completed_iteration[i])
228 			       != iteration)
229 				;
230 		}
231 
232 		ts_diff = timespec_elapsed(start);
233 		vcpu_dirty_total = timespec_add(vcpu_dirty_total, ts_diff);
234 		pr_info("Iteration %d dirty memory time: %ld.%.9lds\n",
235 			iteration, ts_diff.tv_sec, ts_diff.tv_nsec);
236 
237 		clock_gettime(CLOCK_MONOTONIC, &start);
238 		memstress_get_dirty_log(vm, bitmaps, p->slots);
239 		ts_diff = timespec_elapsed(start);
240 		get_dirty_log_total = timespec_add(get_dirty_log_total,
241 						   ts_diff);
242 		pr_info("Iteration %d get dirty log time: %ld.%.9lds\n",
243 			iteration, ts_diff.tv_sec, ts_diff.tv_nsec);
244 
245 		if (dirty_log_manual_caps) {
246 			clock_gettime(CLOCK_MONOTONIC, &start);
247 			memstress_clear_dirty_log(vm, bitmaps, p->slots,
248 						  pages_per_slot);
249 			ts_diff = timespec_elapsed(start);
250 			clear_dirty_log_total = timespec_add(clear_dirty_log_total,
251 							     ts_diff);
252 			pr_info("Iteration %d clear dirty log time: %ld.%.9lds\n",
253 				iteration, ts_diff.tv_sec, ts_diff.tv_nsec);
254 		}
255 	}
256 
257 	/*
258 	 * Run vCPUs while dirty logging is being disabled to stress disabling
259 	 * in terms of both performance and correctness.  Opt-in via command
260 	 * line as this significantly increases time to disable dirty logging.
261 	 */
262 	if (run_vcpus_while_disabling_dirty_logging)
263 		WRITE_ONCE(iteration, -1);
264 
265 	/* Disable dirty logging */
266 	clock_gettime(CLOCK_MONOTONIC, &start);
267 	memstress_disable_dirty_logging(vm, p->slots);
268 	ts_diff = timespec_elapsed(start);
269 	pr_info("Disabling dirty logging time: %ld.%.9lds\n",
270 		ts_diff.tv_sec, ts_diff.tv_nsec);
271 
272 	/*
273 	 * Tell the vCPU threads to quit.  No need to manually check that vCPUs
274 	 * have stopped running after disabling dirty logging, the join will
275 	 * wait for them to exit.
276 	 */
277 	host_quit = true;
278 	memstress_join_vcpu_threads(nr_vcpus);
279 
280 	avg = timespec_div(get_dirty_log_total, p->iterations);
281 	pr_info("Get dirty log over %lu iterations took %ld.%.9lds. (Avg %ld.%.9lds/iteration)\n",
282 		p->iterations, get_dirty_log_total.tv_sec,
283 		get_dirty_log_total.tv_nsec, avg.tv_sec, avg.tv_nsec);
284 
285 	if (dirty_log_manual_caps) {
286 		avg = timespec_div(clear_dirty_log_total, p->iterations);
287 		pr_info("Clear dirty log over %lu iterations took %ld.%.9lds. (Avg %ld.%.9lds/iteration)\n",
288 			p->iterations, clear_dirty_log_total.tv_sec,
289 			clear_dirty_log_total.tv_nsec, avg.tv_sec, avg.tv_nsec);
290 	}
291 
292 	memstress_free_bitmaps(bitmaps, p->slots);
293 	arch_cleanup_vm(vm);
294 	memstress_destroy_vm(vm);
295 }
296 
help(char * name)297 static void help(char *name)
298 {
299 	puts("");
300 	printf("usage: %s [-h] [-a] [-i iterations] [-p offset] [-g] "
301 	       "[-m mode] [-n] [-b vcpu bytes] [-v vcpus] [-o] [-r random seed ] [-s mem type]"
302 	       "[-x memslots] [-w percentage] [-c physical cpus to run test on]\n", name);
303 	puts("");
304 	printf(" -a: access memory randomly rather than in order.\n");
305 	printf(" -i: specify iteration counts (default: %"PRIu64")\n",
306 	       TEST_HOST_LOOP_N);
307 	printf(" -g: Do not enable KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2. This\n"
308 	       "     makes KVM_GET_DIRTY_LOG clear the dirty log (i.e.\n"
309 	       "     KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE is not enabled)\n"
310 	       "     and writes will be tracked as soon as dirty logging is\n"
311 	       "     enabled on the memslot (i.e. KVM_DIRTY_LOG_INITIALLY_SET\n"
312 	       "     is not enabled).\n");
313 	printf(" -p: specify guest physical test memory offset\n"
314 	       "     Warning: a low offset can conflict with the loaded test code.\n");
315 	guest_modes_help();
316 	printf(" -n: Run the vCPUs in nested mode (L2)\n");
317 	printf(" -e: Run vCPUs while dirty logging is being disabled.  This\n"
318 	       "     can significantly increase runtime, especially if there\n"
319 	       "     isn't a dedicated pCPU for the main thread.\n");
320 	printf(" -b: specify the size of the memory region which should be\n"
321 	       "     dirtied by each vCPU. e.g. 10M or 3G.\n"
322 	       "     (default: 1G)\n");
323 	printf(" -v: specify the number of vCPUs to run.\n");
324 	printf(" -o: Overlap guest memory accesses instead of partitioning\n"
325 	       "     them into a separate region of memory for each vCPU.\n");
326 	printf(" -r: specify the starting random seed.\n");
327 	backing_src_help("-s");
328 	printf(" -x: Split the memory region into this number of memslots.\n"
329 	       "     (default: 1)\n");
330 	printf(" -w: specify the percentage of pages which should be written to\n"
331 	       "     as an integer from 0-100 inclusive. This is probabilistic,\n"
332 	       "     so -w X means each page has an X%% chance of writing\n"
333 	       "     and a (100-X)%% chance of reading.\n"
334 	       "     (default: 100 i.e. all pages are written to.)\n");
335 	kvm_print_vcpu_pinning_help();
336 	puts("");
337 	exit(0);
338 }
339 
main(int argc,char * argv[])340 int main(int argc, char *argv[])
341 {
342 	int max_vcpus = kvm_check_cap(KVM_CAP_MAX_VCPUS);
343 	const char *pcpu_list = NULL;
344 	struct test_params p = {
345 		.iterations = TEST_HOST_LOOP_N,
346 		.partition_vcpu_memory_access = true,
347 		.backing_src = DEFAULT_VM_MEM_SRC,
348 		.slots = 1,
349 		.random_seed = 1,
350 		.write_percent = 100,
351 	};
352 	int opt;
353 
354 	dirty_log_manual_caps =
355 		kvm_check_cap(KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2);
356 	dirty_log_manual_caps &= (KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE |
357 				  KVM_DIRTY_LOG_INITIALLY_SET);
358 
359 	guest_modes_append_default();
360 
361 	while ((opt = getopt(argc, argv, "ab:c:eghi:m:nop:r:s:v:x:w:")) != -1) {
362 		switch (opt) {
363 		case 'a':
364 			p.random_access = true;
365 			break;
366 		case 'b':
367 			guest_percpu_mem_size = parse_size(optarg);
368 			break;
369 		case 'c':
370 			pcpu_list = optarg;
371 			break;
372 		case 'e':
373 			/* 'e' is for evil. */
374 			run_vcpus_while_disabling_dirty_logging = true;
375 			break;
376 		case 'g':
377 			dirty_log_manual_caps = 0;
378 			break;
379 		case 'h':
380 			help(argv[0]);
381 			break;
382 		case 'i':
383 			p.iterations = atoi_positive("Number of iterations", optarg);
384 			break;
385 		case 'm':
386 			guest_modes_cmdline(optarg);
387 			break;
388 		case 'n':
389 			memstress_args.nested = true;
390 			break;
391 		case 'o':
392 			p.partition_vcpu_memory_access = false;
393 			break;
394 		case 'p':
395 			p.phys_offset = strtoull(optarg, NULL, 0);
396 			break;
397 		case 'r':
398 			p.random_seed = atoi_positive("Random seed", optarg);
399 			break;
400 		case 's':
401 			p.backing_src = parse_backing_src_type(optarg);
402 			break;
403 		case 'v':
404 			nr_vcpus = atoi_positive("Number of vCPUs", optarg);
405 			TEST_ASSERT(nr_vcpus <= max_vcpus,
406 				    "Invalid number of vcpus, must be between 1 and %d", max_vcpus);
407 			break;
408 		case 'w':
409 			p.write_percent = atoi_non_negative("Write percentage", optarg);
410 			TEST_ASSERT(p.write_percent <= 100,
411 				    "Write percentage must be between 0 and 100");
412 			break;
413 		case 'x':
414 			p.slots = atoi_positive("Number of slots", optarg);
415 			break;
416 		default:
417 			help(argv[0]);
418 			break;
419 		}
420 	}
421 
422 	if (pcpu_list) {
423 		kvm_parse_vcpu_pinning(pcpu_list, memstress_args.vcpu_to_pcpu,
424 				       nr_vcpus);
425 		memstress_args.pin_vcpus = true;
426 	}
427 
428 	TEST_ASSERT(p.iterations >= 2, "The test should have at least two iterations");
429 
430 	pr_info("Test iterations: %"PRIu64"\n",	p.iterations);
431 
432 	for_each_guest_mode(run_test, &p);
433 
434 	return 0;
435 }
436