1 // SPDX-License-Identifier: GPL-2.0
2 #define _GNU_SOURCE /* for program_invocation_short_name */
3 #include <fcntl.h>
4 #include <pthread.h>
5 #include <sched.h>
6 #include <semaphore.h>
7 #include <signal.h>
8 #include <stdio.h>
9 #include <stdlib.h>
10 #include <string.h>
11 #include <sys/ioctl.h>
12 #include <sys/mman.h>
13 
14 #include <linux/compiler.h>
15 
16 #include <test_util.h>
17 #include <kvm_util.h>
18 #include <processor.h>
19 
20 /*
21  * s390x needs at least 1MB alignment, and the x86_64 MOVE/DELETE tests need a
22  * 2MB sized and aligned region so that the initial region corresponds to
23  * exactly one large page.
24  */
25 #define MEM_REGION_SIZE		0x200000
26 
27 #ifdef __x86_64__
28 /*
29  * Somewhat arbitrary location and slot, intended to not overlap anything.
30  */
31 #define MEM_REGION_GPA		0xc0000000
32 #define MEM_REGION_SLOT		10
33 
34 static const uint64_t MMIO_VAL = 0xbeefull;
35 
36 extern const uint64_t final_rip_start;
37 extern const uint64_t final_rip_end;
38 
39 static sem_t vcpu_ready;
40 
41 static inline uint64_t guest_spin_on_val(uint64_t spin_val)
42 {
43 	uint64_t val;
44 
45 	do {
46 		val = READ_ONCE(*((uint64_t *)MEM_REGION_GPA));
47 	} while (val == spin_val);
48 
49 	GUEST_SYNC(0);
50 	return val;
51 }
52 
53 static void *vcpu_worker(void *data)
54 {
55 	struct kvm_vcpu *vcpu = data;
56 	struct kvm_run *run = vcpu->run;
57 	struct ucall uc;
58 	uint64_t cmd;
59 
60 	/*
61 	 * Loop until the guest is done.  Re-enter the guest on all MMIO exits,
62 	 * which will occur if the guest attempts to access a memslot after it
63 	 * has been deleted or while it is being moved .
64 	 */
65 	while (1) {
66 		vcpu_run(vcpu);
67 
68 		if (run->exit_reason == KVM_EXIT_IO) {
69 			cmd = get_ucall(vcpu, &uc);
70 			if (cmd != UCALL_SYNC)
71 				break;
72 
73 			sem_post(&vcpu_ready);
74 			continue;
75 		}
76 
77 		if (run->exit_reason != KVM_EXIT_MMIO)
78 			break;
79 
80 		TEST_ASSERT(!run->mmio.is_write, "Unexpected exit mmio write");
81 		TEST_ASSERT(run->mmio.len == 8,
82 			    "Unexpected exit mmio size = %u", run->mmio.len);
83 
84 		TEST_ASSERT(run->mmio.phys_addr == MEM_REGION_GPA,
85 			    "Unexpected exit mmio address = 0x%llx",
86 			    run->mmio.phys_addr);
87 		memcpy(run->mmio.data, &MMIO_VAL, 8);
88 	}
89 
90 	if (run->exit_reason == KVM_EXIT_IO && cmd == UCALL_ABORT)
91 		REPORT_GUEST_ASSERT(uc);
92 
93 	return NULL;
94 }
95 
96 static void wait_for_vcpu(void)
97 {
98 	struct timespec ts;
99 
100 	TEST_ASSERT(!clock_gettime(CLOCK_REALTIME, &ts),
101 		    "clock_gettime() failed: %d\n", errno);
102 
103 	ts.tv_sec += 2;
104 	TEST_ASSERT(!sem_timedwait(&vcpu_ready, &ts),
105 		    "sem_timedwait() failed: %d\n", errno);
106 
107 	/* Wait for the vCPU thread to reenter the guest. */
108 	usleep(100000);
109 }
110 
111 static struct kvm_vm *spawn_vm(struct kvm_vcpu **vcpu, pthread_t *vcpu_thread,
112 			       void *guest_code)
113 {
114 	struct kvm_vm *vm;
115 	uint64_t *hva;
116 	uint64_t gpa;
117 
118 	vm = vm_create_with_one_vcpu(vcpu, guest_code);
119 
120 	vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS_THP,
121 				    MEM_REGION_GPA, MEM_REGION_SLOT,
122 				    MEM_REGION_SIZE / getpagesize(), 0);
123 
124 	/*
125 	 * Allocate and map two pages so that the GPA accessed by guest_code()
126 	 * stays valid across the memslot move.
127 	 */
128 	gpa = vm_phy_pages_alloc(vm, 2, MEM_REGION_GPA, MEM_REGION_SLOT);
129 	TEST_ASSERT(gpa == MEM_REGION_GPA, "Failed vm_phy_pages_alloc\n");
130 
131 	virt_map(vm, MEM_REGION_GPA, MEM_REGION_GPA, 2);
132 
133 	/* Ditto for the host mapping so that both pages can be zeroed. */
134 	hva = addr_gpa2hva(vm, MEM_REGION_GPA);
135 	memset(hva, 0, 2 * 4096);
136 
137 	pthread_create(vcpu_thread, NULL, vcpu_worker, *vcpu);
138 
139 	/* Ensure the guest thread is spun up. */
140 	wait_for_vcpu();
141 
142 	return vm;
143 }
144 
145 
146 static void guest_code_move_memory_region(void)
147 {
148 	uint64_t val;
149 
150 	GUEST_SYNC(0);
151 
152 	/*
153 	 * Spin until the memory region starts getting moved to a
154 	 * misaligned address.
155 	 * Every region move may or may not trigger MMIO, as the
156 	 * window where the memslot is invalid is usually quite small.
157 	 */
158 	val = guest_spin_on_val(0);
159 	__GUEST_ASSERT(val == 1 || val == MMIO_VAL,
160 		       "Expected '1' or MMIO ('%llx'), got '%llx'", MMIO_VAL, val);
161 
162 	/* Spin until the misaligning memory region move completes. */
163 	val = guest_spin_on_val(MMIO_VAL);
164 	__GUEST_ASSERT(val == 1 || val == 0,
165 		       "Expected '0' or '1' (no MMIO), got '%llx'", val);
166 
167 	/* Spin until the memory region starts to get re-aligned. */
168 	val = guest_spin_on_val(0);
169 	__GUEST_ASSERT(val == 1 || val == MMIO_VAL,
170 		       "Expected '1' or MMIO ('%llx'), got '%llx'", MMIO_VAL, val);
171 
172 	/* Spin until the re-aligning memory region move completes. */
173 	val = guest_spin_on_val(MMIO_VAL);
174 	GUEST_ASSERT_EQ(val, 1);
175 
176 	GUEST_DONE();
177 }
178 
179 static void test_move_memory_region(void)
180 {
181 	pthread_t vcpu_thread;
182 	struct kvm_vcpu *vcpu;
183 	struct kvm_vm *vm;
184 	uint64_t *hva;
185 
186 	vm = spawn_vm(&vcpu, &vcpu_thread, guest_code_move_memory_region);
187 
188 	hva = addr_gpa2hva(vm, MEM_REGION_GPA);
189 
190 	/*
191 	 * Shift the region's base GPA.  The guest should not see "2" as the
192 	 * hva->gpa translation is misaligned, i.e. the guest is accessing a
193 	 * different host pfn.
194 	 */
195 	vm_mem_region_move(vm, MEM_REGION_SLOT, MEM_REGION_GPA - 4096);
196 	WRITE_ONCE(*hva, 2);
197 
198 	/*
199 	 * The guest _might_ see an invalid memslot and trigger MMIO, but it's
200 	 * a tiny window.  Spin and defer the sync until the memslot is
201 	 * restored and guest behavior is once again deterministic.
202 	 */
203 	usleep(100000);
204 
205 	/*
206 	 * Note, value in memory needs to be changed *before* restoring the
207 	 * memslot, else the guest could race the update and see "2".
208 	 */
209 	WRITE_ONCE(*hva, 1);
210 
211 	/* Restore the original base, the guest should see "1". */
212 	vm_mem_region_move(vm, MEM_REGION_SLOT, MEM_REGION_GPA);
213 	wait_for_vcpu();
214 	/* Defered sync from when the memslot was misaligned (above). */
215 	wait_for_vcpu();
216 
217 	pthread_join(vcpu_thread, NULL);
218 
219 	kvm_vm_free(vm);
220 }
221 
222 static void guest_code_delete_memory_region(void)
223 {
224 	uint64_t val;
225 
226 	GUEST_SYNC(0);
227 
228 	/* Spin until the memory region is deleted. */
229 	val = guest_spin_on_val(0);
230 	GUEST_ASSERT_EQ(val, MMIO_VAL);
231 
232 	/* Spin until the memory region is recreated. */
233 	val = guest_spin_on_val(MMIO_VAL);
234 	GUEST_ASSERT_EQ(val, 0);
235 
236 	/* Spin until the memory region is deleted. */
237 	val = guest_spin_on_val(0);
238 	GUEST_ASSERT_EQ(val, MMIO_VAL);
239 
240 	asm("1:\n\t"
241 	    ".pushsection .rodata\n\t"
242 	    ".global final_rip_start\n\t"
243 	    "final_rip_start: .quad 1b\n\t"
244 	    ".popsection");
245 
246 	/* Spin indefinitely (until the code memslot is deleted). */
247 	guest_spin_on_val(MMIO_VAL);
248 
249 	asm("1:\n\t"
250 	    ".pushsection .rodata\n\t"
251 	    ".global final_rip_end\n\t"
252 	    "final_rip_end: .quad 1b\n\t"
253 	    ".popsection");
254 
255 	GUEST_ASSERT(0);
256 }
257 
258 static void test_delete_memory_region(void)
259 {
260 	pthread_t vcpu_thread;
261 	struct kvm_vcpu *vcpu;
262 	struct kvm_regs regs;
263 	struct kvm_run *run;
264 	struct kvm_vm *vm;
265 
266 	vm = spawn_vm(&vcpu, &vcpu_thread, guest_code_delete_memory_region);
267 
268 	/* Delete the memory region, the guest should not die. */
269 	vm_mem_region_delete(vm, MEM_REGION_SLOT);
270 	wait_for_vcpu();
271 
272 	/* Recreate the memory region.  The guest should see "0". */
273 	vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS_THP,
274 				    MEM_REGION_GPA, MEM_REGION_SLOT,
275 				    MEM_REGION_SIZE / getpagesize(), 0);
276 	wait_for_vcpu();
277 
278 	/* Delete the region again so that there's only one memslot left. */
279 	vm_mem_region_delete(vm, MEM_REGION_SLOT);
280 	wait_for_vcpu();
281 
282 	/*
283 	 * Delete the primary memslot.  This should cause an emulation error or
284 	 * shutdown due to the page tables getting nuked.
285 	 */
286 	vm_mem_region_delete(vm, 0);
287 
288 	pthread_join(vcpu_thread, NULL);
289 
290 	run = vcpu->run;
291 
292 	TEST_ASSERT(run->exit_reason == KVM_EXIT_SHUTDOWN ||
293 		    run->exit_reason == KVM_EXIT_INTERNAL_ERROR,
294 		    "Unexpected exit reason = %d", run->exit_reason);
295 
296 	vcpu_regs_get(vcpu, &regs);
297 
298 	/*
299 	 * On AMD, after KVM_EXIT_SHUTDOWN the VMCB has been reinitialized already,
300 	 * so the instruction pointer would point to the reset vector.
301 	 */
302 	if (run->exit_reason == KVM_EXIT_INTERNAL_ERROR)
303 		TEST_ASSERT(regs.rip >= final_rip_start &&
304 			    regs.rip < final_rip_end,
305 			    "Bad rip, expected 0x%lx - 0x%lx, got 0x%llx\n",
306 			    final_rip_start, final_rip_end, regs.rip);
307 
308 	kvm_vm_free(vm);
309 }
310 
311 static void test_zero_memory_regions(void)
312 {
313 	struct kvm_vcpu *vcpu;
314 	struct kvm_vm *vm;
315 
316 	pr_info("Testing KVM_RUN with zero added memory regions\n");
317 
318 	vm = vm_create_barebones();
319 	vcpu = __vm_vcpu_add(vm, 0);
320 
321 	vm_ioctl(vm, KVM_SET_NR_MMU_PAGES, (void *)64ul);
322 	vcpu_run(vcpu);
323 	TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_INTERNAL_ERROR);
324 
325 	kvm_vm_free(vm);
326 }
327 #endif /* __x86_64__ */
328 
329 /*
330  * Test it can be added memory slots up to KVM_CAP_NR_MEMSLOTS, then any
331  * tentative to add further slots should fail.
332  */
333 static void test_add_max_memory_regions(void)
334 {
335 	int ret;
336 	struct kvm_vm *vm;
337 	uint32_t max_mem_slots;
338 	uint32_t slot;
339 	void *mem, *mem_aligned, *mem_extra;
340 	size_t alignment;
341 
342 #ifdef __s390x__
343 	/* On s390x, the host address must be aligned to 1M (due to PGSTEs) */
344 	alignment = 0x100000;
345 #else
346 	alignment = 1;
347 #endif
348 
349 	max_mem_slots = kvm_check_cap(KVM_CAP_NR_MEMSLOTS);
350 	TEST_ASSERT(max_mem_slots > 0,
351 		    "KVM_CAP_NR_MEMSLOTS should be greater than 0");
352 	pr_info("Allowed number of memory slots: %i\n", max_mem_slots);
353 
354 	vm = vm_create_barebones();
355 
356 	/* Check it can be added memory slots up to the maximum allowed */
357 	pr_info("Adding slots 0..%i, each memory region with %dK size\n",
358 		(max_mem_slots - 1), MEM_REGION_SIZE >> 10);
359 
360 	mem = mmap(NULL, (size_t)max_mem_slots * MEM_REGION_SIZE + alignment,
361 		   PROT_READ | PROT_WRITE,
362 		   MAP_PRIVATE | MAP_ANONYMOUS | MAP_NORESERVE, -1, 0);
363 	TEST_ASSERT(mem != MAP_FAILED, "Failed to mmap() host");
364 	mem_aligned = (void *)(((size_t) mem + alignment - 1) & ~(alignment - 1));
365 
366 	for (slot = 0; slot < max_mem_slots; slot++)
367 		vm_set_user_memory_region(vm, slot, 0,
368 					  ((uint64_t)slot * MEM_REGION_SIZE),
369 					  MEM_REGION_SIZE,
370 					  mem_aligned + (uint64_t)slot * MEM_REGION_SIZE);
371 
372 	/* Check it cannot be added memory slots beyond the limit */
373 	mem_extra = mmap(NULL, MEM_REGION_SIZE, PROT_READ | PROT_WRITE,
374 			 MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
375 	TEST_ASSERT(mem_extra != MAP_FAILED, "Failed to mmap() host");
376 
377 	ret = __vm_set_user_memory_region(vm, max_mem_slots, 0,
378 					  (uint64_t)max_mem_slots * MEM_REGION_SIZE,
379 					  MEM_REGION_SIZE, mem_extra);
380 	TEST_ASSERT(ret == -1 && errno == EINVAL,
381 		    "Adding one more memory slot should fail with EINVAL");
382 
383 	munmap(mem, (size_t)max_mem_slots * MEM_REGION_SIZE + alignment);
384 	munmap(mem_extra, MEM_REGION_SIZE);
385 	kvm_vm_free(vm);
386 }
387 
388 int main(int argc, char *argv[])
389 {
390 #ifdef __x86_64__
391 	int i, loops;
392 #endif
393 
394 #ifdef __x86_64__
395 	/*
396 	 * FIXME: the zero-memslot test fails on aarch64 and s390x because
397 	 * KVM_RUN fails with ENOEXEC or EFAULT.
398 	 */
399 	test_zero_memory_regions();
400 #endif
401 
402 	test_add_max_memory_regions();
403 
404 #ifdef __x86_64__
405 	if (argc > 1)
406 		loops = atoi_positive("Number of iterations", argv[1]);
407 	else
408 		loops = 10;
409 
410 	pr_info("Testing MOVE of in-use region, %d loops\n", loops);
411 	for (i = 0; i < loops; i++)
412 		test_move_memory_region();
413 
414 	pr_info("Testing DELETE of in-use region, %d loops\n", loops);
415 	for (i = 0; i < loops; i++)
416 		test_delete_memory_region();
417 #endif
418 
419 	return 0;
420 }
421