guest_memfd_test.c

  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Copyright Intel Corporation, 2023
  4 *
  5 * Author: Chao Peng <chao.p.peng@linux.intel.com>
  6 */
  7#include <stdlib.h>
  8#include <string.h>
  9#include <unistd.h>
 10#include <errno.h>
 11#include <stdio.h>
 12#include <fcntl.h>
 13
 14#include <linux/bitmap.h>
 15#include <linux/falloc.h>
 16#include <linux/sizes.h>
 17#include <sys/mman.h>
 18#include <sys/types.h>
 19#include <sys/stat.h>
 20
 21#include "kvm_util.h"
 22#include "numaif.h"
 23#include "test_util.h"
 24#include "ucall_common.h"
 25
 26static size_t page_size;
 27
 28static void test_file_read_write(int fd, size_t total_size)
 29{
 30	char buf[64];
 31
 32	TEST_ASSERT(read(fd, buf, sizeof(buf)) < 0,
 33		    "read on a guest_mem fd should fail");
 34	TEST_ASSERT(write(fd, buf, sizeof(buf)) < 0,
 35		    "write on a guest_mem fd should fail");
 36	TEST_ASSERT(pread(fd, buf, sizeof(buf), 0) < 0,
 37		    "pread on a guest_mem fd should fail");
 38	TEST_ASSERT(pwrite(fd, buf, sizeof(buf), 0) < 0,
 39		    "pwrite on a guest_mem fd should fail");
 40}
 41
 42static void test_mmap_cow(int fd, size_t size)
 43{
 44	void *mem;
 45
 46	mem = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
 47	TEST_ASSERT(mem == MAP_FAILED, "Copy-on-write not allowed by guest_memfd.");
 48}
 49
 50static void test_mmap_supported(int fd, size_t total_size)
 51{
 52	const char val = 0xaa;
 53	char *mem;
 54	size_t i;
 55	int ret;
 56
 57	mem = kvm_mmap(total_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd);
 58
 59	memset(mem, val, total_size);
 60	for (i = 0; i < total_size; i++)
 61		TEST_ASSERT_EQ(READ_ONCE(mem[i]), val);
 62
 63	ret = fallocate(fd, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE, 0,
 64			page_size);
 65	TEST_ASSERT(!ret, "fallocate the first page should succeed.");
 66
 67	for (i = 0; i < page_size; i++)
 68		TEST_ASSERT_EQ(READ_ONCE(mem[i]), 0x00);
 69	for (; i < total_size; i++)
 70		TEST_ASSERT_EQ(READ_ONCE(mem[i]), val);
 71
 72	memset(mem, val, page_size);
 73	for (i = 0; i < total_size; i++)
 74		TEST_ASSERT_EQ(READ_ONCE(mem[i]), val);
 75
 76	kvm_munmap(mem, total_size);
 77}
 78
 79static void test_mbind(int fd, size_t total_size)
 80{
 81	const unsigned long nodemask_0 = 1; /* nid: 0 */
 82	unsigned long nodemask = 0;
 83	unsigned long maxnode = 8;
 84	int policy;
 85	char *mem;
 86	int ret;
 87
 88	if (!is_multi_numa_node_system())
 89		return;
 90
 91	mem = kvm_mmap(total_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd);
 92
 93	/* Test MPOL_INTERLEAVE policy */
 94	kvm_mbind(mem, page_size * 2, MPOL_INTERLEAVE, &nodemask_0, maxnode, 0);
 95	kvm_get_mempolicy(&policy, &nodemask, maxnode, mem, MPOL_F_ADDR);
 96	TEST_ASSERT(policy == MPOL_INTERLEAVE && nodemask == nodemask_0,
 97		    "Wanted MPOL_INTERLEAVE (%u) and nodemask 0x%lx, got %u and 0x%lx",
 98		    MPOL_INTERLEAVE, nodemask_0, policy, nodemask);
 99
100	/* Test basic MPOL_BIND policy */
101	kvm_mbind(mem + page_size * 2, page_size * 2, MPOL_BIND, &nodemask_0, maxnode, 0);
102	kvm_get_mempolicy(&policy, &nodemask, maxnode, mem + page_size * 2, MPOL_F_ADDR);
103	TEST_ASSERT(policy == MPOL_BIND && nodemask == nodemask_0,
104		    "Wanted MPOL_BIND (%u) and nodemask 0x%lx, got %u and 0x%lx",
105		    MPOL_BIND, nodemask_0, policy, nodemask);
106
107	/* Test MPOL_DEFAULT policy */
108	kvm_mbind(mem, total_size, MPOL_DEFAULT, NULL, 0, 0);
109	kvm_get_mempolicy(&policy, &nodemask, maxnode, mem, MPOL_F_ADDR);
110	TEST_ASSERT(policy == MPOL_DEFAULT && !nodemask,
111		    "Wanted MPOL_DEFAULT (%u) and nodemask 0x0, got %u and 0x%lx",
112		    MPOL_DEFAULT, policy, nodemask);
113
114	/* Test with invalid policy */
115	ret = mbind(mem, page_size, 999, &nodemask_0, maxnode, 0);
116	TEST_ASSERT(ret == -1 && errno == EINVAL,
117		    "mbind with invalid policy should fail with EINVAL");
118
119	kvm_munmap(mem, total_size);
120}
121
122static void test_numa_allocation(int fd, size_t total_size)
123{
124	unsigned long node0_mask = 1;  /* Node 0 */
125	unsigned long node1_mask = 2;  /* Node 1 */
126	unsigned long maxnode = 8;
127	void *pages[4];
128	int status[4];
129	char *mem;
130	int i;
131
132	if (!is_multi_numa_node_system())
133		return;
134
135	mem = kvm_mmap(total_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd);
136
137	for (i = 0; i < 4; i++)
138		pages[i] = (char *)mem + page_size * i;
139
140	/* Set NUMA policy after allocation */
141	memset(mem, 0xaa, page_size);
142	kvm_mbind(pages[0], page_size, MPOL_BIND, &node0_mask, maxnode, 0);
143	kvm_fallocate(fd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, 0, page_size);
144
145	/* Set NUMA policy before allocation */
146	kvm_mbind(pages[0], page_size * 2, MPOL_BIND, &node1_mask, maxnode, 0);
147	kvm_mbind(pages[2], page_size * 2, MPOL_BIND, &node0_mask, maxnode, 0);
148	memset(mem, 0xaa, total_size);
149
150	/* Validate if pages are allocated on specified NUMA nodes */
151	kvm_move_pages(0, 4, pages, NULL, status, 0);
152	TEST_ASSERT(status[0] == 1, "Expected page 0 on node 1, got it on node %d", status[0]);
153	TEST_ASSERT(status[1] == 1, "Expected page 1 on node 1, got it on node %d", status[1]);
154	TEST_ASSERT(status[2] == 0, "Expected page 2 on node 0, got it on node %d", status[2]);
155	TEST_ASSERT(status[3] == 0, "Expected page 3 on node 0, got it on node %d", status[3]);
156
157	/* Punch hole for all pages */
158	kvm_fallocate(fd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, 0, total_size);
159
160	/* Change NUMA policy nodes and reallocate */
161	kvm_mbind(pages[0], page_size * 2, MPOL_BIND, &node0_mask, maxnode, 0);
162	kvm_mbind(pages[2], page_size * 2, MPOL_BIND, &node1_mask, maxnode, 0);
163	memset(mem, 0xaa, total_size);
164
165	kvm_move_pages(0, 4, pages, NULL, status, 0);
166	TEST_ASSERT(status[0] == 0, "Expected page 0 on node 0, got it on node %d", status[0]);
167	TEST_ASSERT(status[1] == 0, "Expected page 1 on node 0, got it on node %d", status[1]);
168	TEST_ASSERT(status[2] == 1, "Expected page 2 on node 1, got it on node %d", status[2]);
169	TEST_ASSERT(status[3] == 1, "Expected page 3 on node 1, got it on node %d", status[3]);
170
171	kvm_munmap(mem, total_size);
172}
173
174static void test_fault_sigbus(int fd, size_t accessible_size, size_t map_size)
175{
176	const char val = 0xaa;
177	char *mem;
178	size_t i;
179
180	mem = kvm_mmap(map_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd);
181
182	TEST_EXPECT_SIGBUS(memset(mem, val, map_size));
183	TEST_EXPECT_SIGBUS((void)READ_ONCE(mem[accessible_size]));
184
185	for (i = 0; i < accessible_size; i++)
186		TEST_ASSERT_EQ(READ_ONCE(mem[i]), val);
187
188	kvm_munmap(mem, map_size);
189}
190
191static void test_fault_overflow(int fd, size_t total_size)
192{
193	test_fault_sigbus(fd, total_size, total_size * 4);
194}
195
196static void test_fault_private(int fd, size_t total_size)
197{
198	test_fault_sigbus(fd, 0, total_size);
199}
200
201static void test_mmap_not_supported(int fd, size_t total_size)
202{
203	char *mem;
204
205	mem = mmap(NULL, page_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
206	TEST_ASSERT_EQ(mem, MAP_FAILED);
207
208	mem = mmap(NULL, total_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
209	TEST_ASSERT_EQ(mem, MAP_FAILED);
210}
211
212static void test_file_size(int fd, size_t total_size)
213{
214	struct stat sb;
215	int ret;
216
217	ret = fstat(fd, &sb);
218	TEST_ASSERT(!ret, "fstat should succeed");
219	TEST_ASSERT_EQ(sb.st_size, total_size);
220	TEST_ASSERT_EQ(sb.st_blksize, page_size);
221}
222
223static void test_fallocate(int fd, size_t total_size)
224{
225	int ret;
226
227	ret = fallocate(fd, FALLOC_FL_KEEP_SIZE, 0, total_size);
228	TEST_ASSERT(!ret, "fallocate with aligned offset and size should succeed");
229
230	ret = fallocate(fd, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE,
231			page_size - 1, page_size);
232	TEST_ASSERT(ret, "fallocate with unaligned offset should fail");
233
234	ret = fallocate(fd, FALLOC_FL_KEEP_SIZE, total_size, page_size);
235	TEST_ASSERT(ret, "fallocate beginning at total_size should fail");
236
237	ret = fallocate(fd, FALLOC_FL_KEEP_SIZE, total_size + page_size, page_size);
238	TEST_ASSERT(ret, "fallocate beginning after total_size should fail");
239
240	ret = fallocate(fd, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE,
241			total_size, page_size);
242	TEST_ASSERT(!ret, "fallocate(PUNCH_HOLE) at total_size should succeed");
243
244	ret = fallocate(fd, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE,
245			total_size + page_size, page_size);
246	TEST_ASSERT(!ret, "fallocate(PUNCH_HOLE) after total_size should succeed");
247
248	ret = fallocate(fd, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE,
249			page_size, page_size - 1);
250	TEST_ASSERT(ret, "fallocate with unaligned size should fail");
251
252	ret = fallocate(fd, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE,
253			page_size, page_size);
254	TEST_ASSERT(!ret, "fallocate(PUNCH_HOLE) with aligned offset and size should succeed");
255
256	ret = fallocate(fd, FALLOC_FL_KEEP_SIZE, page_size, page_size);
257	TEST_ASSERT(!ret, "fallocate to restore punched hole should succeed");
258}
259
260static void test_invalid_punch_hole(int fd, size_t total_size)
261{
262	struct {
263		off_t offset;
264		off_t len;
265	} testcases[] = {
266		{0, 1},
267		{0, page_size - 1},
268		{0, page_size + 1},
269
270		{1, 1},
271		{1, page_size - 1},
272		{1, page_size},
273		{1, page_size + 1},
274
275		{page_size, 1},
276		{page_size, page_size - 1},
277		{page_size, page_size + 1},
278	};
279	int ret, i;
280
281	for (i = 0; i < ARRAY_SIZE(testcases); i++) {
282		ret = fallocate(fd, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE,
283				testcases[i].offset, testcases[i].len);
284		TEST_ASSERT(ret == -1 && errno == EINVAL,
285			    "PUNCH_HOLE with !PAGE_SIZE offset (%lx) and/or length (%lx) should fail",
286			    testcases[i].offset, testcases[i].len);
287	}
288}
289
290static void test_create_guest_memfd_invalid_sizes(struct kvm_vm *vm,
291						  uint64_t guest_memfd_flags)
292{
293	size_t size;
294	int fd;
295
296	for (size = 1; size < page_size; size++) {
297		fd = __vm_create_guest_memfd(vm, size, guest_memfd_flags);
298		TEST_ASSERT(fd < 0 && errno == EINVAL,
299			    "guest_memfd() with non-page-aligned page size '0x%lx' should fail with EINVAL",
300			    size);
301	}
302}
303
304static void test_create_guest_memfd_multiple(struct kvm_vm *vm)
305{
306	int fd1, fd2, ret;
307	struct stat st1, st2;
308
309	fd1 = __vm_create_guest_memfd(vm, page_size, 0);
310	TEST_ASSERT(fd1 != -1, "memfd creation should succeed");
311
312	ret = fstat(fd1, &st1);
313	TEST_ASSERT(ret != -1, "memfd fstat should succeed");
314	TEST_ASSERT(st1.st_size == page_size, "memfd st_size should match requested size");
315
316	fd2 = __vm_create_guest_memfd(vm, page_size * 2, 0);
317	TEST_ASSERT(fd2 != -1, "memfd creation should succeed");
318
319	ret = fstat(fd2, &st2);
320	TEST_ASSERT(ret != -1, "memfd fstat should succeed");
321	TEST_ASSERT(st2.st_size == page_size * 2, "second memfd st_size should match requested size");
322
323	ret = fstat(fd1, &st1);
324	TEST_ASSERT(ret != -1, "memfd fstat should succeed");
325	TEST_ASSERT(st1.st_size == page_size, "first memfd st_size should still match requested size");
326	TEST_ASSERT(st1.st_ino != st2.st_ino, "different memfd should have different inode numbers");
327
328	close(fd2);
329	close(fd1);
330}
331
332static void test_guest_memfd_flags(struct kvm_vm *vm)
333{
334	uint64_t valid_flags = vm_check_cap(vm, KVM_CAP_GUEST_MEMFD_FLAGS);
335	uint64_t flag;
336	int fd;
337
338	for (flag = BIT(0); flag; flag <<= 1) {
339		fd = __vm_create_guest_memfd(vm, page_size, flag);
340		if (flag & valid_flags) {
341			TEST_ASSERT(fd >= 0,
342				    "guest_memfd() with flag '0x%lx' should succeed",
343				    flag);
344			close(fd);
345		} else {
346			TEST_ASSERT(fd < 0 && errno == EINVAL,
347				    "guest_memfd() with flag '0x%lx' should fail with EINVAL",
348				    flag);
349		}
350	}
351}
352
353#define gmem_test(__test, __vm, __flags)				\
354do {									\
355	int fd = vm_create_guest_memfd(__vm, page_size * 4, __flags);	\
356									\
357	test_##__test(fd, page_size * 4);				\
358	close(fd);							\
359} while (0)
360
361static void __test_guest_memfd(struct kvm_vm *vm, uint64_t flags)
362{
363	test_create_guest_memfd_multiple(vm);
364	test_create_guest_memfd_invalid_sizes(vm, flags);
365
366	gmem_test(file_read_write, vm, flags);
367
368	if (flags & GUEST_MEMFD_FLAG_MMAP) {
369		if (flags & GUEST_MEMFD_FLAG_INIT_SHARED) {
370			gmem_test(mmap_supported, vm, flags);
371			gmem_test(fault_overflow, vm, flags);
372			gmem_test(numa_allocation, vm, flags);
373		} else {
374			gmem_test(fault_private, vm, flags);
375		}
376
377		gmem_test(mmap_cow, vm, flags);
378		gmem_test(mbind, vm, flags);
379	} else {
380		gmem_test(mmap_not_supported, vm, flags);
381	}
382
383	gmem_test(file_size, vm, flags);
384	gmem_test(fallocate, vm, flags);
385	gmem_test(invalid_punch_hole, vm, flags);
386}
387
388static void test_guest_memfd(unsigned long vm_type)
389{
390	struct kvm_vm *vm = vm_create_barebones_type(vm_type);
391	uint64_t flags;
392
393	test_guest_memfd_flags(vm);
394
395	__test_guest_memfd(vm, 0);
396
397	flags = vm_check_cap(vm, KVM_CAP_GUEST_MEMFD_FLAGS);
398	if (flags & GUEST_MEMFD_FLAG_MMAP)
399		__test_guest_memfd(vm, GUEST_MEMFD_FLAG_MMAP);
400
401	/* MMAP should always be supported if INIT_SHARED is supported. */
402	if (flags & GUEST_MEMFD_FLAG_INIT_SHARED)
403		__test_guest_memfd(vm, GUEST_MEMFD_FLAG_MMAP |
404				       GUEST_MEMFD_FLAG_INIT_SHARED);
405
406	kvm_vm_free(vm);
407}
408
409static void guest_code(uint8_t *mem, uint64_t size)
410{
411	size_t i;
412
413	for (i = 0; i < size; i++)
414		__GUEST_ASSERT(mem[i] == 0xaa,
415			       "Guest expected 0xaa at offset %lu, got 0x%x", i, mem[i]);
416
417	memset(mem, 0xff, size);
418	GUEST_DONE();
419}
420
421static void test_guest_memfd_guest(void)
422{
423	/*
424	 * Skip the first 4gb and slot0.  slot0 maps <1gb and is used to back
425	 * the guest's code, stack, and page tables, and low memory contains
426	 * the PCI hole and other MMIO regions that need to be avoided.
427	 */
428	const uint64_t gpa = SZ_4G;
429	const int slot = 1;
430
431	struct kvm_vcpu *vcpu;
432	struct kvm_vm *vm;
433	uint8_t *mem;
434	size_t size;
435	int fd, i;
436
437	if (!kvm_check_cap(KVM_CAP_GUEST_MEMFD_FLAGS))
438		return;
439
440	vm = __vm_create_shape_with_one_vcpu(VM_SHAPE_DEFAULT, &vcpu, 1, guest_code);
441
442	TEST_ASSERT(vm_check_cap(vm, KVM_CAP_GUEST_MEMFD_FLAGS) & GUEST_MEMFD_FLAG_MMAP,
443		    "Default VM type should support MMAP, supported flags = 0x%x",
444		    vm_check_cap(vm, KVM_CAP_GUEST_MEMFD_FLAGS));
445	TEST_ASSERT(vm_check_cap(vm, KVM_CAP_GUEST_MEMFD_FLAGS) & GUEST_MEMFD_FLAG_INIT_SHARED,
446		    "Default VM type should support INIT_SHARED, supported flags = 0x%x",
447		    vm_check_cap(vm, KVM_CAP_GUEST_MEMFD_FLAGS));
448
449	size = vm->page_size;
450	fd = vm_create_guest_memfd(vm, size, GUEST_MEMFD_FLAG_MMAP |
451					     GUEST_MEMFD_FLAG_INIT_SHARED);
452	vm_set_user_memory_region2(vm, slot, KVM_MEM_GUEST_MEMFD, gpa, size, NULL, fd, 0);
453
454	mem = kvm_mmap(size, PROT_READ | PROT_WRITE, MAP_SHARED, fd);
455	memset(mem, 0xaa, size);
456	kvm_munmap(mem, size);
457
458	virt_pg_map(vm, gpa, gpa);
459	vcpu_args_set(vcpu, 2, gpa, size);
460	vcpu_run(vcpu);
461
462	TEST_ASSERT_EQ(get_ucall(vcpu, NULL), UCALL_DONE);
463
464	mem = kvm_mmap(size, PROT_READ | PROT_WRITE, MAP_SHARED, fd);
465	for (i = 0; i < size; i++)
466		TEST_ASSERT_EQ(mem[i], 0xff);
467
468	close(fd);
469	kvm_vm_free(vm);
470}
471
472int main(int argc, char *argv[])
473{
474	unsigned long vm_types, vm_type;
475
476	TEST_REQUIRE(kvm_has_cap(KVM_CAP_GUEST_MEMFD));
477
478	page_size = getpagesize();
479
480	/*
481	 * Not all architectures support KVM_CAP_VM_TYPES. However, those that
482	 * support guest_memfd have that support for the default VM type.
483	 */
484	vm_types = kvm_check_cap(KVM_CAP_VM_TYPES);
485	if (!vm_types)
486		vm_types = BIT(VM_TYPE_DEFAULT);
487
488	for_each_set_bit(vm_type, &vm_types, BITS_PER_TYPE(vm_types))
489		test_guest_memfd(vm_type);
490
491	test_guest_memfd_guest();
492}