summaryrefslogtreecommitdiff
path: root/tools/testing/selftests/kvm/lib/memstress.c
blob: cf2c739713080f3f55e1383fb5d0a9e65f5d1dc7 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2020, Google LLC.
 */
#define _GNU_SOURCE

#include <inttypes.h>
#include <linux/bitmap.h>

#include "kvm_util.h"
#include "memstress.h"
#include "processor.h"

struct memstress_args memstress_args;

/*
 * Guest virtual memory offset of the testing memory slot.
 * Must not conflict with identity mapped test code.
 */
static uint64_t guest_test_virt_mem = DEFAULT_GUEST_TEST_MEM;

struct vcpu_thread {
	/* The index of the vCPU. */
	int vcpu_idx;

	/* The pthread backing the vCPU. */
	pthread_t thread;

	/* Set to true once the vCPU thread is up and running. */
	bool running;
};

/* The vCPU threads involved in this test. */
static struct vcpu_thread vcpu_threads[KVM_MAX_VCPUS];

/* The function run by each vCPU thread, as provided by the test. */
static void (*vcpu_thread_fn)(struct memstress_vcpu_args *);

/* Set to true once all vCPU threads are up and running. */
static bool all_vcpu_threads_running;

static struct kvm_vcpu *vcpus[KVM_MAX_VCPUS];

/*
 * Continuously write to the first 8 bytes of each page in the
 * specified region.
 */
void memstress_guest_code(uint32_t vcpu_idx)
{
	struct memstress_args *args = &memstress_args;
	struct memstress_vcpu_args *vcpu_args = &args->vcpu_args[vcpu_idx];
	struct guest_random_state rand_state;
	uint64_t gva;
	uint64_t pages;
	uint64_t addr;
	uint64_t page;
	int i;

	rand_state = new_guest_random_state(args->random_seed + vcpu_idx);

	gva = vcpu_args->gva;
	pages = vcpu_args->pages;

	/* Make sure vCPU args data structure is not corrupt. */
	GUEST_ASSERT(vcpu_args->vcpu_idx == vcpu_idx);

	while (true) {
		for (i = 0; i < sizeof(memstress_args); i += args->guest_page_size)
			(void) *((volatile char *)args + i);

		for (i = 0; i < pages; i++) {
			if (args->random_access)
				page = guest_random_u32(&rand_state) % pages;
			else
				page = i;

			addr = gva + (page * args->guest_page_size);

			if (guest_random_u32(&rand_state) % 100 < args->write_percent)
				*(uint64_t *)addr = 0x0123456789ABCDEF;
			else
				READ_ONCE(*(uint64_t *)addr);
		}

		GUEST_SYNC(1);
	}
}

void memstress_setup_vcpus(struct kvm_vm *vm, int nr_vcpus,
			   struct kvm_vcpu *vcpus[],
			   uint64_t vcpu_memory_bytes,
			   bool partition_vcpu_memory_access)
{
	struct memstress_args *args = &memstress_args;
	struct memstress_vcpu_args *vcpu_args;
	int i;

	for (i = 0; i < nr_vcpus; i++) {
		vcpu_args = &args->vcpu_args[i];

		vcpu_args->vcpu = vcpus[i];
		vcpu_args->vcpu_idx = i;

		if (partition_vcpu_memory_access) {
			vcpu_args->gva = guest_test_virt_mem +
					 (i * vcpu_memory_bytes);
			vcpu_args->pages = vcpu_memory_bytes /
					   args->guest_page_size;
			vcpu_args->gpa = args->gpa + (i * vcpu_memory_bytes);
		} else {
			vcpu_args->gva = guest_test_virt_mem;
			vcpu_args->pages = (nr_vcpus * vcpu_memory_bytes) /
					   args->guest_page_size;
			vcpu_args->gpa = args->gpa;
		}

		vcpu_args_set(vcpus[i], 1, i);

		pr_debug("Added VCPU %d with test mem gpa [%lx, %lx)\n",
			 i, vcpu_args->gpa, vcpu_args->gpa +
			 (vcpu_args->pages * args->guest_page_size));
	}
}

struct kvm_vm *memstress_create_vm(enum vm_guest_mode mode, int nr_vcpus,
				   uint64_t vcpu_memory_bytes, int slots,
				   enum vm_mem_backing_src_type backing_src,
				   bool partition_vcpu_memory_access)
{
	struct memstress_args *args = &memstress_args;
	struct kvm_vm *vm;
	uint64_t guest_num_pages, slot0_pages = 0;
	uint64_t backing_src_pagesz = get_backing_src_pagesz(backing_src);
	uint64_t region_end_gfn;
	int i;

	pr_info("Testing guest mode: %s\n", vm_guest_mode_string(mode));

	/* By default vCPUs will write to memory. */
	args->write_percent = 100;

	/*
	 * Snapshot the non-huge page size.  This is used by the guest code to
	 * access/dirty pages at the logging granularity.
	 */
	args->guest_page_size = vm_guest_mode_params[mode].page_size;

	guest_num_pages = vm_adjust_num_guest_pages(mode,
				(nr_vcpus * vcpu_memory_bytes) / args->guest_page_size);

	TEST_ASSERT(vcpu_memory_bytes % getpagesize() == 0,
		    "Guest memory size is not host page size aligned.");
	TEST_ASSERT(vcpu_memory_bytes % args->guest_page_size == 0,
		    "Guest memory size is not guest page size aligned.");
	TEST_ASSERT(guest_num_pages % slots == 0,
		    "Guest memory cannot be evenly divided into %d slots.",
		    slots);

	/*
	 * If using nested, allocate extra pages for the nested page tables and
	 * in-memory data structures.
	 */
	if (args->nested)
		slot0_pages += memstress_nested_pages(nr_vcpus);

	/*
	 * Pass guest_num_pages to populate the page tables for test memory.
	 * The memory is also added to memslot 0, but that's a benign side
	 * effect as KVM allows aliasing HVAs in meslots.
	 */
	vm = __vm_create_with_vcpus(VM_SHAPE(mode), nr_vcpus,
				    slot0_pages + guest_num_pages,
				    memstress_guest_code, vcpus);

	args->vm = vm;

	/* Put the test region at the top guest physical memory. */
	region_end_gfn = vm->max_gfn + 1;

#ifdef __x86_64__
	/*
	 * When running vCPUs in L2, restrict the test region to 48 bits to
	 * avoid needing 5-level page tables to identity map L2.
	 */
	if (args->nested)
		region_end_gfn = min(region_end_gfn, (1UL << 48) / args->guest_page_size);
#endif
	/*
	 * If there should be more memory in the guest test region than there
	 * can be pages in the guest, it will definitely cause problems.
	 */
	TEST_ASSERT(guest_num_pages < region_end_gfn,
		    "Requested more guest memory than address space allows.\n"
		    "    guest pages: %" PRIx64 " max gfn: %" PRIx64
		    " nr_vcpus: %d wss: %" PRIx64 "]",
		    guest_num_pages, region_end_gfn - 1, nr_vcpus, vcpu_memory_bytes);

	args->gpa = (region_end_gfn - guest_num_pages - 1) * args->guest_page_size;
	args->gpa = align_down(args->gpa, backing_src_pagesz);
#ifdef __s390x__
	/* Align to 1M (segment size) */
	args->gpa = align_down(args->gpa, 1 << 20);
#endif
	args->size = guest_num_pages * args->guest_page_size;
	pr_info("guest physical test memory: [0x%lx, 0x%lx)\n",
		args->gpa, args->gpa + args->size);

	/* Add extra memory slots for testing */
	for (i = 0; i < slots; i++) {
		uint64_t region_pages = guest_num_pages / slots;
		vm_paddr_t region_start = args->gpa + region_pages * args->guest_page_size * i;

		vm_userspace_mem_region_add(vm, backing_src, region_start,
					    MEMSTRESS_MEM_SLOT_INDEX + i,
					    region_pages, 0);
	}

	/* Do mapping for the demand paging memory slot */
	virt_map(vm, guest_test_virt_mem, args->gpa, guest_num_pages);

	memstress_setup_vcpus(vm, nr_vcpus, vcpus, vcpu_memory_bytes,
			      partition_vcpu_memory_access);

	if (args->nested) {
		pr_info("Configuring vCPUs to run in L2 (nested).\n");
		memstress_setup_nested(vm, nr_vcpus, vcpus);
	}

	/* Export the shared variables to the guest. */
	sync_global_to_guest(vm, memstress_args);

	return vm;
}

void memstress_destroy_vm(struct kvm_vm *vm)
{
	kvm_vm_free(vm);
}

void memstress_set_write_percent(struct kvm_vm *vm, uint32_t write_percent)
{
	memstress_args.write_percent = write_percent;
	sync_global_to_guest(vm, memstress_args.write_percent);
}

void memstress_set_random_seed(struct kvm_vm *vm, uint32_t random_seed)
{
	memstress_args.random_seed = random_seed;
	sync_global_to_guest(vm, memstress_args.random_seed);
}

void memstress_set_random_access(struct kvm_vm *vm, bool random_access)
{
	memstress_args.random_access = random_access;
	sync_global_to_guest(vm, memstress_args.random_access);
}

uint64_t __weak memstress_nested_pages(int nr_vcpus)
{
	return 0;
}

void __weak memstress_setup_nested(struct kvm_vm *vm, int nr_vcpus, struct kvm_vcpu **vcpus)
{
	pr_info("%s() not support on this architecture, skipping.\n", __func__);
	exit(KSFT_SKIP);
}

static void *vcpu_thread_main(void *data)
{
	struct vcpu_thread *vcpu = data;
	int vcpu_idx = vcpu->vcpu_idx;

	if (memstress_args.pin_vcpus)
		kvm_pin_this_task_to_pcpu(memstress_args.vcpu_to_pcpu[vcpu_idx]);

	WRITE_ONCE(vcpu->running, true);

	/*
	 * Wait for all vCPU threads to be up and running before calling the test-
	 * provided vCPU thread function. This prevents thread creation (which
	 * requires taking the mmap_sem in write mode) from interfering with the
	 * guest faulting in its memory.
	 */
	while (!READ_ONCE(all_vcpu_threads_running))
		;

	vcpu_thread_fn(&memstress_args.vcpu_args[vcpu_idx]);

	return NULL;
}

void memstress_start_vcpu_threads(int nr_vcpus,
				  void (*vcpu_fn)(struct memstress_vcpu_args *))
{
	int i;

	vcpu_thread_fn = vcpu_fn;
	WRITE_ONCE(all_vcpu_threads_running, false);
	WRITE_ONCE(memstress_args.stop_vcpus, false);

	for (i = 0; i < nr_vcpus; i++) {
		struct vcpu_thread *vcpu = &vcpu_threads[i];

		vcpu->vcpu_idx = i;
		WRITE_ONCE(vcpu->running, false);

		pthread_create(&vcpu->thread, NULL, vcpu_thread_main, vcpu);
	}

	for (i = 0; i < nr_vcpus; i++) {
		while (!READ_ONCE(vcpu_threads[i].running))
			;
	}

	WRITE_ONCE(all_vcpu_threads_running, true);
}

void memstress_join_vcpu_threads(int nr_vcpus)
{
	int i;

	WRITE_ONCE(memstress_args.stop_vcpus, true);

	for (i = 0; i < nr_vcpus; i++)
		pthread_join(vcpu_threads[i].thread, NULL);
}

static void toggle_dirty_logging(struct kvm_vm *vm, int slots, bool enable)
{
	int i;

	for (i = 0; i < slots; i++) {
		int slot = MEMSTRESS_MEM_SLOT_INDEX + i;
		int flags = enable ? KVM_MEM_LOG_DIRTY_PAGES : 0;

		vm_mem_region_set_flags(vm, slot, flags);
	}
}

void memstress_enable_dirty_logging(struct kvm_vm *vm, int slots)
{
	toggle_dirty_logging(vm, slots, true);
}

void memstress_disable_dirty_logging(struct kvm_vm *vm, int slots)
{
	toggle_dirty_logging(vm, slots, false);
}

void memstress_get_dirty_log(struct kvm_vm *vm, unsigned long *bitmaps[], int slots)
{
	int i;

	for (i = 0; i < slots; i++) {
		int slot = MEMSTRESS_MEM_SLOT_INDEX + i;

		kvm_vm_get_dirty_log(vm, slot, bitmaps[i]);
	}
}

void memstress_clear_dirty_log(struct kvm_vm *vm, unsigned long *bitmaps[],
			       int slots, uint64_t pages_per_slot)
{
	int i;

	for (i = 0; i < slots; i++) {
		int slot = MEMSTRESS_MEM_SLOT_INDEX + i;

		kvm_vm_clear_dirty_log(vm, slot, bitmaps[i], 0, pages_per_slot);
	}
}

unsigned long **memstress_alloc_bitmaps(int slots, uint64_t pages_per_slot)
{
	unsigned long **bitmaps;
	int i;

	bitmaps = malloc(slots * sizeof(bitmaps[0]));
	TEST_ASSERT(bitmaps, "Failed to allocate bitmaps array.");

	for (i = 0; i < slots; i++) {
		bitmaps[i] = bitmap_zalloc(pages_per_slot);
		TEST_ASSERT(bitmaps[i], "Failed to allocate slot bitmap.");
	}

	return bitmaps;
}

void memstress_free_bitmaps(unsigned long *bitmaps[], int slots)
{
	int i;

	for (i = 0; i < slots; i++)
		free(bitmaps[i]);

	free(bitmaps);
}