summaryrefslogtreecommitdiff
path: root/tools/testing/selftests/kvm/lib/perf_test_util.c
blob: 9618b37c66f7ebee6c613e1b95e1ffa28382f8a2 (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
// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2020, Google LLC.
 */
#include <inttypes.h>

#include "kvm_util.h"
#include "perf_test_util.h"
#include "processor.h"

struct perf_test_args perf_test_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 perf_test_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 perf_test_guest_code(uint32_t vcpu_idx)
{
	struct perf_test_args *pta = &perf_test_args;
	struct perf_test_vcpu_args *vcpu_args = &pta->vcpu_args[vcpu_idx];
	uint64_t gva;
	uint64_t pages;
	int i;

	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 < pages; i++) {
			uint64_t addr = gva + (i * pta->guest_page_size);

			if (i % pta->wr_fract == 0)
				*(uint64_t *)addr = 0x0123456789ABCDEF;
			else
				READ_ONCE(*(uint64_t *)addr);
		}

		GUEST_SYNC(1);
	}
}

void perf_test_setup_vcpus(struct kvm_vm *vm, int nr_vcpus,
			   struct kvm_vcpu *vcpus[],
			   uint64_t vcpu_memory_bytes,
			   bool partition_vcpu_memory_access)
{
	struct perf_test_args *pta = &perf_test_args;
	struct perf_test_vcpu_args *vcpu_args;
	int i;

	for (i = 0; i < nr_vcpus; i++) {
		vcpu_args = &pta->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 /
					   pta->guest_page_size;
			vcpu_args->gpa = pta->gpa + (i * vcpu_memory_bytes);
		} else {
			vcpu_args->gva = guest_test_virt_mem;
			vcpu_args->pages = (nr_vcpus * vcpu_memory_bytes) /
					   pta->guest_page_size;
			vcpu_args->gpa = pta->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 * pta->guest_page_size));
	}
}

struct kvm_vm *perf_test_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 perf_test_args *pta = &perf_test_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. */
	pta->wr_fract = 1;

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

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

	TEST_ASSERT(vcpu_memory_bytes % getpagesize() == 0,
		    "Guest memory size is not host page size aligned.");
	TEST_ASSERT(vcpu_memory_bytes % pta->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 (pta->nested)
		slot0_pages += perf_test_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(mode, nr_vcpus, slot0_pages + guest_num_pages,
				    perf_test_guest_code, vcpus);

	pta->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 (pta->nested)
		region_end_gfn = min(region_end_gfn, (1UL << 48) / pta->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 "]\n",
		    guest_num_pages, region_end_gfn - 1, nr_vcpus, vcpu_memory_bytes);

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

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

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

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

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

	ucall_init(vm, NULL);

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

	return vm;
}

void perf_test_destroy_vm(struct kvm_vm *vm)
{
	ucall_uninit(vm);
	kvm_vm_free(vm);
}

void perf_test_set_wr_fract(struct kvm_vm *vm, int wr_fract)
{
	perf_test_args.wr_fract = wr_fract;
	sync_global_to_guest(vm, perf_test_args);
}

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

void __weak perf_test_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;

	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(&perf_test_args.vcpu_args[vcpu->vcpu_idx]);

	return NULL;
}

void perf_test_start_vcpu_threads(int nr_vcpus,
				  void (*vcpu_fn)(struct perf_test_vcpu_args *))
{
	int i;

	vcpu_thread_fn = vcpu_fn;
	WRITE_ONCE(all_vcpu_threads_running, 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 perf_test_join_vcpu_threads(int nr_vcpus)
{
	int i;

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