1 // SPDX-License-Identifier: GPL-2.0
2 #include <stdio.h>
3 #include <stdlib.h>
4 #include <pthread.h>
5 #include <semaphore.h>
6 #include <sys/types.h>
7 #include <signal.h>
8 #include <errno.h>
9 #include <linux/bitmap.h>
10 #include <linux/bitops.h>
11 #include <linux/atomic.h>
12 #include <linux/sizes.h>
13
14 #include "kvm_util.h"
15 #include "test_util.h"
16 #include "guest_modes.h"
17 #include "processor.h"
18
19 static void guest_code(uint64_t start_gpa, uint64_t end_gpa, uint64_t stride)
20 {
21 uint64_t gpa;
22
23 for (;;) {
24 for (gpa = start_gpa; gpa < end_gpa; gpa += stride)
25 *((volatile uint64_t *)gpa) = gpa;
26 GUEST_SYNC(0);
27 }
28 }
29
30 struct vcpu_info {
31 struct kvm_vcpu *vcpu;
32 uint64_t start_gpa;
33 uint64_t end_gpa;
34 };
35
36 static int nr_vcpus;
37 static atomic_t rendezvous;
38
39 static void rendezvous_with_boss(void)
40 {
41 int orig = atomic_read(&rendezvous);
42
43 if (orig > 0) {
44 atomic_dec_and_test(&rendezvous);
45 while (atomic_read(&rendezvous) > 0)
46 cpu_relax();
47 } else {
48 atomic_inc(&rendezvous);
49 while (atomic_read(&rendezvous) < 0)
50 cpu_relax();
51 }
52 }
53
54 static void run_vcpu(struct kvm_vcpu *vcpu)
55 {
56 vcpu_run(vcpu);
57 TEST_ASSERT_EQ(get_ucall(vcpu, NULL), UCALL_SYNC);
58 }
59
60 static void *vcpu_worker(void *data)
61 {
62 struct vcpu_info *info = data;
63 struct kvm_vcpu *vcpu = info->vcpu;
64 struct kvm_vm *vm = vcpu->vm;
65 struct kvm_sregs sregs;
66
67 vcpu_args_set(vcpu, 3, info->start_gpa, info->end_gpa, vm->page_size);
68
69 rendezvous_with_boss();
70
71 run_vcpu(vcpu);
72 rendezvous_with_boss();
73 vcpu_sregs_get(vcpu, &sregs);
74 #ifdef __x86_64__
75 /* Toggle CR0.WP to trigger a MMU context reset. */
76 sregs.cr0 ^= X86_CR0_WP;
77 #endif
78 vcpu_sregs_set(vcpu, &sregs);
79 rendezvous_with_boss();
80
81 run_vcpu(vcpu);
82 rendezvous_with_boss();
83
84 return NULL;
85 }
86
87 static pthread_t *spawn_workers(struct kvm_vm *vm, struct kvm_vcpu **vcpus,
88 uint64_t start_gpa, uint64_t end_gpa)
89 {
90 struct vcpu_info *info;
91 uint64_t gpa, nr_bytes;
92 pthread_t *threads;
93 int i;
94
95 threads = malloc(nr_vcpus * sizeof(*threads));
96 TEST_ASSERT(threads, "Failed to allocate vCPU threads");
97
98 info = malloc(nr_vcpus * sizeof(*info));
99 TEST_ASSERT(info, "Failed to allocate vCPU gpa ranges");
100
101 nr_bytes = ((end_gpa - start_gpa) / nr_vcpus) &
102 ~((uint64_t)vm->page_size - 1);
103 TEST_ASSERT(nr_bytes, "C'mon, no way you have %d CPUs", nr_vcpus);
104
105 for (i = 0, gpa = start_gpa; i < nr_vcpus; i++, gpa += nr_bytes) {
106 info[i].vcpu = vcpus[i];
107 info[i].start_gpa = gpa;
108 info[i].end_gpa = gpa + nr_bytes;
109 pthread_create(&threads[i], NULL, vcpu_worker, &info[i]);
110 }
111 return threads;
112 }
113
114 static void rendezvous_with_vcpus(struct timespec *time, const char *name)
115 {
116 int i, rendezvoused;
117
118 pr_info("Waiting for vCPUs to finish %s...\n", name);
119
120 rendezvoused = atomic_read(&rendezvous);
121 for (i = 0; abs(rendezvoused) != 1; i++) {
122 usleep(100);
123 if (!(i & 0x3f))
124 pr_info("\r%d vCPUs haven't rendezvoused...",
125 abs(rendezvoused) - 1);
126 rendezvoused = atomic_read(&rendezvous);
127 }
128
129 clock_gettime(CLOCK_MONOTONIC, time);
130
131 /* Release the vCPUs after getting the time of the previous action. */
132 pr_info("\rAll vCPUs finished %s, releasing...\n", name);
133 if (rendezvoused > 0)
134 atomic_set(&rendezvous, -nr_vcpus - 1);
135 else
136 atomic_set(&rendezvous, nr_vcpus + 1);
137 }
138
139 static void calc_default_nr_vcpus(void)
140 {
141 cpu_set_t possible_mask;
142 int r;
143
144 r = sched_getaffinity(0, sizeof(possible_mask), &possible_mask);
145 TEST_ASSERT(!r, "sched_getaffinity failed, errno = %d (%s)",
146 errno, strerror(errno));
147
148 nr_vcpus = CPU_COUNT(&possible_mask) * 3/4;
149 TEST_ASSERT(nr_vcpus > 0, "Uh, no CPUs?");
150 }
151
152 int main(int argc, char *argv[])
153 {
154 /*
155 * Skip the first 4gb and slot0. slot0 maps <1gb and is used to back
156 * the guest's code, stack, and page tables. Because selftests creates
157 * an IRQCHIP, a.k.a. a local APIC, KVM creates an internal memslot
158 * just below the 4gb boundary. This test could create memory at
159 * 1gb-3gb,but it's simpler to skip straight to 4gb.
160 */
161 const uint64_t start_gpa = SZ_4G;
162 const int first_slot = 1;
163
164 struct timespec time_start, time_run1, time_reset, time_run2;
165 uint64_t max_gpa, gpa, slot_size, max_mem, i;
166 int max_slots, slot, opt, fd;
167 bool hugepages = false;
168 struct kvm_vcpu **vcpus;
169 pthread_t *threads;
170 struct kvm_vm *vm;
171 void *mem;
172
173 /*
174 * Default to 2gb so that maxing out systems with MAXPHADDR=46, which
175 * are quite common for x86, requires changing only max_mem (KVM allows
176 * 32k memslots, 32k * 2gb == ~64tb of guest memory).
177 */
178 slot_size = SZ_2G;
179
180 max_slots = kvm_check_cap(KVM_CAP_NR_MEMSLOTS);
181 TEST_ASSERT(max_slots > first_slot, "KVM is broken");
182
183 /* All KVM MMUs should be able to survive a 128gb guest. */
184 max_mem = 128ull * SZ_1G;
185
186 calc_default_nr_vcpus();
187
188 while ((opt = getopt(argc, argv, "c:h:m:s:H")) != -1) {
189 switch (opt) {
190 case 'c':
191 nr_vcpus = atoi_positive("Number of vCPUs", optarg);
192 break;
193 case 'm':
194 max_mem = 1ull * atoi_positive("Memory size", optarg) * SZ_1G;
195 break;
196 case 's':
197 slot_size = 1ull * atoi_positive("Slot size", optarg) * SZ_1G;
198 break;
199 case 'H':
200 hugepages = true;
201 break;
202 case 'h':
203 default:
204 printf("usage: %s [-c nr_vcpus] [-m max_mem_in_gb] [-s slot_size_in_gb] [-H]\n", argv[0]);
205 exit(1);
206 }
207 }
208
209 vcpus = malloc(nr_vcpus * sizeof(*vcpus));
210 TEST_ASSERT(vcpus, "Failed to allocate vCPU array");
211
212 vm = vm_create_with_vcpus(nr_vcpus, guest_code, vcpus);
213
214 max_gpa = vm->max_gfn << vm->page_shift;
215 TEST_ASSERT(max_gpa > (4 * slot_size), "MAXPHYADDR <4gb ");
216
217 fd = kvm_memfd_alloc(slot_size, hugepages);
218 mem = mmap(NULL, slot_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
219 TEST_ASSERT(mem != MAP_FAILED, "mmap() failed");
220
221 TEST_ASSERT(!madvise(mem, slot_size, MADV_NOHUGEPAGE), "madvise() failed");
222
223 /* Pre-fault the memory to avoid taking mmap_sem on guest page faults. */
224 for (i = 0; i < slot_size; i += vm->page_size)
225 ((uint8_t *)mem)[i] = 0xaa;
226
227 gpa = 0;
228 for (slot = first_slot; slot < max_slots; slot++) {
229 gpa = start_gpa + ((slot - first_slot) * slot_size);
230 if (gpa + slot_size > max_gpa)
231 break;
232
233 if ((gpa - start_gpa) >= max_mem)
234 break;
235
236 vm_set_user_memory_region(vm, slot, 0, gpa, slot_size, mem);
237
238 #ifdef __x86_64__
239 /* Identity map memory in the guest using 1gb pages. */
240 for (i = 0; i < slot_size; i += SZ_1G)
241 __virt_pg_map(vm, gpa + i, gpa + i, PG_LEVEL_1G);
242 #else
243 for (i = 0; i < slot_size; i += vm->page_size)
244 virt_pg_map(vm, gpa + i, gpa + i);
245 #endif
246 }
247
248 atomic_set(&rendezvous, nr_vcpus + 1);
249 threads = spawn_workers(vm, vcpus, start_gpa, gpa);
250
251 free(vcpus);
252 vcpus = NULL;
253
254 pr_info("Running with %lugb of guest memory and %u vCPUs\n",
255 (gpa - start_gpa) / SZ_1G, nr_vcpus);
256
257 rendezvous_with_vcpus(&time_start, "spawning");
258 rendezvous_with_vcpus(&time_run1, "run 1");
259 rendezvous_with_vcpus(&time_reset, "reset");
260 rendezvous_with_vcpus(&time_run2, "run 2");
261
262 time_run2 = timespec_sub(time_run2, time_reset);
263 time_reset = timespec_sub(time_reset, time_run1);
264 time_run1 = timespec_sub(time_run1, time_start);
265
266 pr_info("run1 = %ld.%.9lds, reset = %ld.%.9lds, run2 = %ld.%.9lds\n",
267 time_run1.tv_sec, time_run1.tv_nsec,
268 time_reset.tv_sec, time_reset.tv_nsec,
269 time_run2.tv_sec, time_run2.tv_nsec);
270
271 /*
272 * Delete even numbered slots (arbitrary) and unmap the first half of
273 * the backing (also arbitrary) to verify KVM correctly drops all
274 * references to the removed regions.
275 */
276 for (slot = (slot - 1) & ~1ull; slot >= first_slot; slot -= 2)
277 vm_set_user_memory_region(vm, slot, 0, 0, 0, NULL);
278
279 munmap(mem, slot_size / 2);
280
281 /* Sanity check that the vCPUs actually ran. */
282 for (i = 0; i < nr_vcpus; i++)
283 pthread_join(threads[i], NULL);
284
285 /*
286 * Deliberately exit without deleting the remaining memslots or closing
287 * kvm_fd to test cleanup via mmu_notifier.release.
288 */
289 }
290
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