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
28static int gic_fd;
29
30static 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
39static void arch_cleanup_vm(struct kvm_vm *vm)
40{
41	if (gic_fd > 0)
42		close(gic_fd);
43}
44
45#else /* __aarch64__ */
46
47static void arch_setup_vm(struct kvm_vm *vm, unsigned int nr_vcpus)
48{
49}
50
51static 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
60static int nr_vcpus = 1;
61static uint64_t guest_percpu_mem_size = DEFAULT_PER_VCPU_MEM_SIZE;
62static bool run_vcpus_while_disabling_dirty_logging;
63
64/* Host variables */
65static u64 dirty_log_manual_caps;
66static bool host_quit;
67static int iteration;
68static int vcpu_last_completed_iteration[KVM_MAX_VCPUS];
69
70static 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", ret);
92		TEST_ASSERT(get_ucall(vcpu, NULL) == UCALL_SYNC,
93			    "Invalid guest sync status: exit_reason=%s",
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
128struct 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
139static 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
297static 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
340int 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