1 // SPDX-License-Identifier: GPL-2.0
2 #define _GNU_SOURCE
3
4 #include <stdio.h>
5 #include <stdlib.h>
6 #include <pthread.h>
7 #include <semaphore.h>
8 #include <sys/types.h>
9 #include <signal.h>
10 #include <errno.h>
11 #include <linux/bitmap.h>
12 #include <linux/bitops.h>
13 #include <linux/atomic.h>
14
15 #include "kvm_util.h"
16 #include "test_util.h"
17 #include "guest_modes.h"
18 #include "processor.h"
19
guest_code(uint64_t start_gpa,uint64_t end_gpa,uint64_t stride)20 static void guest_code(uint64_t start_gpa, uint64_t end_gpa, uint64_t stride)
21 {
22 uint64_t gpa;
23
24 for (gpa = start_gpa; gpa < end_gpa; gpa += stride)
25 *((volatile uint64_t *)gpa) = gpa;
26
27 GUEST_DONE();
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
rendezvous_with_boss(void)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
run_vcpu(struct kvm_vm * vm,uint32_t vcpu_id)54 static void run_vcpu(struct kvm_vm *vm, uint32_t vcpu_id)
55 {
56 vcpu_run(vm, vcpu_id);
57 ASSERT_EQ(get_ucall(vm, vcpu_id, NULL), UCALL_DONE);
58 }
59
vcpu_worker(void * data)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 struct kvm_regs regs;
67
68 vcpu_args_set(vm, vcpu->id, 3, info->start_gpa, info->end_gpa,
69 vm_get_page_size(vm));
70
71 /* Snapshot regs before the first run. */
72 vcpu_regs_get(vm, vcpu->id, ®s);
73 rendezvous_with_boss();
74
75 run_vcpu(vm, vcpu->id);
76 rendezvous_with_boss();
77 vcpu_regs_set(vm, vcpu->id, ®s);
78 vcpu_sregs_get(vm, vcpu->id, &sregs);
79 #ifdef __x86_64__
80 /* Toggle CR0.WP to trigger a MMU context reset. */
81 sregs.cr0 ^= X86_CR0_WP;
82 #endif
83 vcpu_sregs_set(vm, vcpu->id, &sregs);
84 rendezvous_with_boss();
85
86 run_vcpu(vm, vcpu->id);
87 rendezvous_with_boss();
88
89 return NULL;
90 }
91
spawn_workers(struct kvm_vm * vm,struct kvm_vcpu ** vcpus,uint64_t start_gpa,uint64_t end_gpa)92 static pthread_t *spawn_workers(struct kvm_vm *vm, struct kvm_vcpu **vcpus,
93 uint64_t start_gpa, uint64_t end_gpa)
94 {
95 struct vcpu_info *info;
96 uint64_t gpa, nr_bytes;
97 pthread_t *threads;
98 int i;
99
100 threads = malloc(nr_vcpus * sizeof(*threads));
101 TEST_ASSERT(threads, "Failed to allocate vCPU threads");
102
103 info = malloc(nr_vcpus * sizeof(*info));
104 TEST_ASSERT(info, "Failed to allocate vCPU gpa ranges");
105
106 nr_bytes = ((end_gpa - start_gpa) / nr_vcpus) &
107 ~((uint64_t)vm_get_page_size(vm) - 1);
108 TEST_ASSERT(nr_bytes, "C'mon, no way you have %d CPUs", nr_vcpus);
109
110 for (i = 0, gpa = start_gpa; i < nr_vcpus; i++, gpa += nr_bytes) {
111 info[i].vcpu = vcpus[i];
112 info[i].start_gpa = gpa;
113 info[i].end_gpa = gpa + nr_bytes;
114 pthread_create(&threads[i], NULL, vcpu_worker, &info[i]);
115 }
116 return threads;
117 }
118
rendezvous_with_vcpus(struct timespec * time,const char * name)119 static void rendezvous_with_vcpus(struct timespec *time, const char *name)
120 {
121 int i, rendezvoused;
122
123 pr_info("Waiting for vCPUs to finish %s...\n", name);
124
125 rendezvoused = atomic_read(&rendezvous);
126 for (i = 0; abs(rendezvoused) != 1; i++) {
127 usleep(100);
128 if (!(i & 0x3f))
129 pr_info("\r%d vCPUs haven't rendezvoused...",
130 abs(rendezvoused) - 1);
131 rendezvoused = atomic_read(&rendezvous);
132 }
133
134 clock_gettime(CLOCK_MONOTONIC, time);
135
136 /* Release the vCPUs after getting the time of the previous action. */
137 pr_info("\rAll vCPUs finished %s, releasing...\n", name);
138 if (rendezvoused > 0)
139 atomic_set(&rendezvous, -nr_vcpus - 1);
140 else
141 atomic_set(&rendezvous, nr_vcpus + 1);
142 }
143
calc_default_nr_vcpus(void)144 static void calc_default_nr_vcpus(void)
145 {
146 cpu_set_t possible_mask;
147 int r;
148
149 r = sched_getaffinity(0, sizeof(possible_mask), &possible_mask);
150 TEST_ASSERT(!r, "sched_getaffinity failed, errno = %d (%s)",
151 errno, strerror(errno));
152
153 nr_vcpus = CPU_COUNT(&possible_mask) * 3/4;
154 TEST_ASSERT(nr_vcpus > 0, "Uh, no CPUs?");
155 }
156
main(int argc,char * argv[])157 int main(int argc, char *argv[])
158 {
159 /*
160 * Skip the first 4gb and slot0. slot0 maps <1gb and is used to back
161 * the guest's code, stack, and page tables. Because selftests creates
162 * an IRQCHIP, a.k.a. a local APIC, KVM creates an internal memslot
163 * just below the 4gb boundary. This test could create memory at
164 * 1gb-3gb,but it's simpler to skip straight to 4gb.
165 */
166 const uint64_t size_1gb = (1 << 30);
167 const uint64_t start_gpa = (4ull * size_1gb);
168 const int first_slot = 1;
169
170 struct timespec time_start, time_run1, time_reset, time_run2;
171 uint64_t max_gpa, gpa, slot_size, max_mem, i;
172 int max_slots, slot, opt, fd;
173 bool hugepages = false;
174 struct kvm_vcpu **vcpus;
175 pthread_t *threads;
176 struct kvm_vm *vm;
177 void *mem;
178
179 /*
180 * Default to 2gb so that maxing out systems with MAXPHADDR=46, which
181 * are quite common for x86, requires changing only max_mem (KVM allows
182 * 32k memslots, 32k * 2gb == ~64tb of guest memory).
183 */
184 slot_size = 2 * size_1gb;
185
186 max_slots = kvm_check_cap(KVM_CAP_NR_MEMSLOTS);
187 TEST_ASSERT(max_slots > first_slot, "KVM is broken");
188
189 /* All KVM MMUs should be able to survive a 128gb guest. */
190 max_mem = 128 * size_1gb;
191
192 calc_default_nr_vcpus();
193
194 while ((opt = getopt(argc, argv, "c:h:m:s:H")) != -1) {
195 switch (opt) {
196 case 'c':
197 nr_vcpus = atoi(optarg);
198 TEST_ASSERT(nr_vcpus > 0, "number of vcpus must be >0");
199 break;
200 case 'm':
201 max_mem = atoi(optarg) * size_1gb;
202 TEST_ASSERT(max_mem > 0, "memory size must be >0");
203 break;
204 case 's':
205 slot_size = atoi(optarg) * size_1gb;
206 TEST_ASSERT(slot_size > 0, "slot size must be >0");
207 break;
208 case 'H':
209 hugepages = true;
210 break;
211 case 'h':
212 default:
213 printf("usage: %s [-c nr_vcpus] [-m max_mem_in_gb] [-s slot_size_in_gb] [-H]\n", argv[0]);
214 exit(1);
215 }
216 }
217
218 vcpus = malloc(nr_vcpus * sizeof(*vcpus));
219 TEST_ASSERT(vcpus, "Failed to allocate vCPU array");
220
221 vm = vm_create_with_vcpus(nr_vcpus, guest_code, vcpus);
222
223 max_gpa = vm_get_max_gfn(vm) << vm_get_page_shift(vm);
224 TEST_ASSERT(max_gpa > (4 * slot_size), "MAXPHYADDR <4gb ");
225
226 fd = kvm_memfd_alloc(slot_size, hugepages);
227 mem = mmap(NULL, slot_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
228 TEST_ASSERT(mem != MAP_FAILED, "mmap() failed");
229
230 TEST_ASSERT(!madvise(mem, slot_size, MADV_NOHUGEPAGE), "madvise() failed");
231
232 /* Pre-fault the memory to avoid taking mmap_sem on guest page faults. */
233 for (i = 0; i < slot_size; i += vm_get_page_size(vm))
234 ((uint8_t *)mem)[i] = 0xaa;
235
236 gpa = 0;
237 for (slot = first_slot; slot < max_slots; slot++) {
238 gpa = start_gpa + ((slot - first_slot) * slot_size);
239 if (gpa + slot_size > max_gpa)
240 break;
241
242 if ((gpa - start_gpa) >= max_mem)
243 break;
244
245 vm_set_user_memory_region(vm, slot, 0, gpa, slot_size, mem);
246
247 #ifdef __x86_64__
248 /* Identity map memory in the guest using 1gb pages. */
249 for (i = 0; i < slot_size; i += size_1gb)
250 __virt_pg_map(vm, gpa + i, gpa + i, PG_LEVEL_1G);
251 #else
252 for (i = 0; i < slot_size; i += vm_get_page_size(vm))
253 virt_pg_map(vm, gpa + i, gpa + i);
254 #endif
255 }
256
257 atomic_set(&rendezvous, nr_vcpus + 1);
258 threads = spawn_workers(vm, vcpus, start_gpa, gpa);
259
260 free(vcpus);
261 vcpus = NULL;
262
263 pr_info("Running with %lugb of guest memory and %u vCPUs\n",
264 (gpa - start_gpa) / size_1gb, nr_vcpus);
265
266 rendezvous_with_vcpus(&time_start, "spawning");
267 rendezvous_with_vcpus(&time_run1, "run 1");
268 rendezvous_with_vcpus(&time_reset, "reset");
269 rendezvous_with_vcpus(&time_run2, "run 2");
270
271 time_run2 = timespec_sub(time_run2, time_reset);
272 time_reset = timespec_sub(time_reset, time_run1);
273 time_run1 = timespec_sub(time_run1, time_start);
274
275 pr_info("run1 = %ld.%.9lds, reset = %ld.%.9lds, run2 = %ld.%.9lds\n",
276 time_run1.tv_sec, time_run1.tv_nsec,
277 time_reset.tv_sec, time_reset.tv_nsec,
278 time_run2.tv_sec, time_run2.tv_nsec);
279
280 /*
281 * Delete even numbered slots (arbitrary) and unmap the first half of
282 * the backing (also arbitrary) to verify KVM correctly drops all
283 * references to the removed regions.
284 */
285 for (slot = (slot - 1) & ~1ull; slot >= first_slot; slot -= 2)
286 vm_set_user_memory_region(vm, slot, 0, 0, 0, NULL);
287
288 munmap(mem, slot_size / 2);
289
290 /* Sanity check that the vCPUs actually ran. */
291 for (i = 0; i < nr_vcpus; i++)
292 pthread_join(threads[i], NULL);
293
294 /*
295 * Deliberately exit without deleting the remaining memslots or closing
296 * kvm_fd to test cleanup via mmu_notifier.release.
297 */
298 }
299