1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * GUP long-term page pinning tests.
4 *
5 * Copyright 2023, Red Hat, Inc.
6 *
7 * Author(s): David Hildenbrand <david@redhat.com>
8 */
9 #define _GNU_SOURCE
10 #include <stdlib.h>
11 #include <string.h>
12 #include <stdbool.h>
13 #include <stdint.h>
14 #include <unistd.h>
15 #include <errno.h>
16 #include <fcntl.h>
17 #include <assert.h>
18 #include <sys/mman.h>
19 #include <sys/ioctl.h>
20 #include <sys/vfs.h>
21 #include <linux/magic.h>
22 #include <linux/memfd.h>
23
24 #include "local_config.h"
25 #ifdef LOCAL_CONFIG_HAVE_LIBURING
26 #include <liburing.h>
27 #endif /* LOCAL_CONFIG_HAVE_LIBURING */
28
29 #include "../../../../mm/gup_test.h"
30 #include "../kselftest.h"
31 #include "vm_util.h"
32
33 static size_t pagesize;
34 static int nr_hugetlbsizes;
35 static size_t hugetlbsizes[10];
36 static int gup_fd;
37
get_fs_type(int fd)38 static __fsword_t get_fs_type(int fd)
39 {
40 struct statfs fs;
41 int ret;
42
43 do {
44 ret = fstatfs(fd, &fs);
45 } while (ret && errno == EINTR);
46
47 return ret ? 0 : fs.f_type;
48 }
49
fs_is_unknown(__fsword_t fs_type)50 static bool fs_is_unknown(__fsword_t fs_type)
51 {
52 /*
53 * We only support some filesystems in our tests when dealing with
54 * R/W long-term pinning. For these filesystems, we can be fairly sure
55 * whether they support it or not.
56 */
57 switch (fs_type) {
58 case TMPFS_MAGIC:
59 case HUGETLBFS_MAGIC:
60 case BTRFS_SUPER_MAGIC:
61 case EXT4_SUPER_MAGIC:
62 case XFS_SUPER_MAGIC:
63 return false;
64 default:
65 return true;
66 }
67 }
68
fs_supports_writable_longterm_pinning(__fsword_t fs_type)69 static bool fs_supports_writable_longterm_pinning(__fsword_t fs_type)
70 {
71 assert(!fs_is_unknown(fs_type));
72 switch (fs_type) {
73 case TMPFS_MAGIC:
74 case HUGETLBFS_MAGIC:
75 return true;
76 default:
77 return false;
78 }
79 }
80
81 enum test_type {
82 TEST_TYPE_RO,
83 TEST_TYPE_RO_FAST,
84 TEST_TYPE_RW,
85 TEST_TYPE_RW_FAST,
86 #ifdef LOCAL_CONFIG_HAVE_LIBURING
87 TEST_TYPE_IOURING,
88 #endif /* LOCAL_CONFIG_HAVE_LIBURING */
89 };
90
do_test(int fd,size_t size,enum test_type type,bool shared)91 static void do_test(int fd, size_t size, enum test_type type, bool shared)
92 {
93 __fsword_t fs_type = get_fs_type(fd);
94 bool should_work;
95 char *mem;
96 int ret;
97
98 if (ftruncate(fd, size)) {
99 ksft_test_result_fail("ftruncate() failed\n");
100 return;
101 }
102
103 if (fallocate(fd, 0, 0, size)) {
104 if (size == pagesize)
105 ksft_test_result_fail("fallocate() failed\n");
106 else
107 ksft_test_result_skip("need more free huge pages\n");
108 return;
109 }
110
111 mem = mmap(NULL, size, PROT_READ | PROT_WRITE,
112 shared ? MAP_SHARED : MAP_PRIVATE, fd, 0);
113 if (mem == MAP_FAILED) {
114 if (size == pagesize || shared)
115 ksft_test_result_fail("mmap() failed\n");
116 else
117 ksft_test_result_skip("need more free huge pages\n");
118 return;
119 }
120
121 /*
122 * Fault in the page writable such that GUP-fast can eventually pin
123 * it immediately.
124 */
125 memset(mem, 0, size);
126
127 switch (type) {
128 case TEST_TYPE_RO:
129 case TEST_TYPE_RO_FAST:
130 case TEST_TYPE_RW:
131 case TEST_TYPE_RW_FAST: {
132 struct pin_longterm_test args;
133 const bool fast = type == TEST_TYPE_RO_FAST ||
134 type == TEST_TYPE_RW_FAST;
135 const bool rw = type == TEST_TYPE_RW ||
136 type == TEST_TYPE_RW_FAST;
137
138 if (gup_fd < 0) {
139 ksft_test_result_skip("gup_test not available\n");
140 break;
141 }
142
143 if (rw && shared && fs_is_unknown(fs_type)) {
144 ksft_test_result_skip("Unknown filesystem\n");
145 return;
146 }
147 /*
148 * R/O pinning or pinning in a private mapping is always
149 * expected to work. Otherwise, we expect long-term R/W pinning
150 * to only succeed for special fielesystems.
151 */
152 should_work = !shared || !rw ||
153 fs_supports_writable_longterm_pinning(fs_type);
154
155 args.addr = (__u64)(uintptr_t)mem;
156 args.size = size;
157 args.flags = fast ? PIN_LONGTERM_TEST_FLAG_USE_FAST : 0;
158 args.flags |= rw ? PIN_LONGTERM_TEST_FLAG_USE_WRITE : 0;
159 ret = ioctl(gup_fd, PIN_LONGTERM_TEST_START, &args);
160 if (ret && errno == EINVAL) {
161 ksft_test_result_skip("PIN_LONGTERM_TEST_START failed\n");
162 break;
163 } else if (ret && errno == EFAULT) {
164 ksft_test_result(!should_work, "Should have failed\n");
165 break;
166 } else if (ret) {
167 ksft_test_result_fail("PIN_LONGTERM_TEST_START failed\n");
168 break;
169 }
170
171 if (ioctl(gup_fd, PIN_LONGTERM_TEST_STOP))
172 ksft_print_msg("[INFO] PIN_LONGTERM_TEST_STOP failed\n");
173
174 /*
175 * TODO: if the kernel ever supports long-term R/W pinning on
176 * some previously unsupported filesystems, we might want to
177 * perform some additional tests for possible data corruptions.
178 */
179 ksft_test_result(should_work, "Should have worked\n");
180 break;
181 }
182 #ifdef LOCAL_CONFIG_HAVE_LIBURING
183 case TEST_TYPE_IOURING: {
184 struct io_uring ring;
185 struct iovec iov;
186
187 /* io_uring always pins pages writable. */
188 if (shared && fs_is_unknown(fs_type)) {
189 ksft_test_result_skip("Unknown filesystem\n");
190 return;
191 }
192 should_work = !shared ||
193 fs_supports_writable_longterm_pinning(fs_type);
194
195 /* Skip on errors, as we might just lack kernel support. */
196 ret = io_uring_queue_init(1, &ring, 0);
197 if (ret < 0) {
198 ksft_test_result_skip("io_uring_queue_init() failed\n");
199 break;
200 }
201 /*
202 * Register the range as a fixed buffer. This will FOLL_WRITE |
203 * FOLL_PIN | FOLL_LONGTERM the range.
204 */
205 iov.iov_base = mem;
206 iov.iov_len = size;
207 ret = io_uring_register_buffers(&ring, &iov, 1);
208 /* Only new kernels return EFAULT. */
209 if (ret && (errno == ENOSPC || errno == EOPNOTSUPP ||
210 errno == EFAULT)) {
211 ksft_test_result(!should_work, "Should have failed\n");
212 } else if (ret) {
213 /*
214 * We might just lack support or have insufficient
215 * MEMLOCK limits.
216 */
217 ksft_test_result_skip("io_uring_register_buffers() failed\n");
218 } else {
219 ksft_test_result(should_work, "Should have worked\n");
220 io_uring_unregister_buffers(&ring);
221 }
222
223 io_uring_queue_exit(&ring);
224 break;
225 }
226 #endif /* LOCAL_CONFIG_HAVE_LIBURING */
227 default:
228 assert(false);
229 }
230
231 munmap(mem, size);
232 }
233
234 typedef void (*test_fn)(int fd, size_t size);
235
run_with_memfd(test_fn fn,const char * desc)236 static void run_with_memfd(test_fn fn, const char *desc)
237 {
238 int fd;
239
240 ksft_print_msg("[RUN] %s ... with memfd\n", desc);
241
242 fd = memfd_create("test", 0);
243 if (fd < 0) {
244 ksft_test_result_fail("memfd_create() failed\n");
245 return;
246 }
247
248 fn(fd, pagesize);
249 close(fd);
250 }
251
run_with_tmpfile(test_fn fn,const char * desc)252 static void run_with_tmpfile(test_fn fn, const char *desc)
253 {
254 FILE *file;
255 int fd;
256
257 ksft_print_msg("[RUN] %s ... with tmpfile\n", desc);
258
259 file = tmpfile();
260 if (!file) {
261 ksft_test_result_fail("tmpfile() failed\n");
262 return;
263 }
264
265 fd = fileno(file);
266 if (fd < 0) {
267 ksft_test_result_fail("fileno() failed\n");
268 return;
269 }
270
271 fn(fd, pagesize);
272 fclose(file);
273 }
274
run_with_local_tmpfile(test_fn fn,const char * desc)275 static void run_with_local_tmpfile(test_fn fn, const char *desc)
276 {
277 char filename[] = __FILE__"_tmpfile_XXXXXX";
278 int fd;
279
280 ksft_print_msg("[RUN] %s ... with local tmpfile\n", desc);
281
282 fd = mkstemp(filename);
283 if (fd < 0) {
284 ksft_test_result_fail("mkstemp() failed\n");
285 return;
286 }
287
288 if (unlink(filename)) {
289 ksft_test_result_fail("unlink() failed\n");
290 goto close;
291 }
292
293 fn(fd, pagesize);
294 close:
295 close(fd);
296 }
297
run_with_memfd_hugetlb(test_fn fn,const char * desc,size_t hugetlbsize)298 static void run_with_memfd_hugetlb(test_fn fn, const char *desc,
299 size_t hugetlbsize)
300 {
301 int flags = MFD_HUGETLB;
302 int fd;
303
304 ksft_print_msg("[RUN] %s ... with memfd hugetlb (%zu kB)\n", desc,
305 hugetlbsize / 1024);
306
307 flags |= __builtin_ctzll(hugetlbsize) << MFD_HUGE_SHIFT;
308
309 fd = memfd_create("test", flags);
310 if (fd < 0) {
311 ksft_test_result_skip("memfd_create() failed\n");
312 return;
313 }
314
315 fn(fd, hugetlbsize);
316 close(fd);
317 }
318
319 struct test_case {
320 const char *desc;
321 test_fn fn;
322 };
323
test_shared_rw_pin(int fd,size_t size)324 static void test_shared_rw_pin(int fd, size_t size)
325 {
326 do_test(fd, size, TEST_TYPE_RW, true);
327 }
328
test_shared_rw_fast_pin(int fd,size_t size)329 static void test_shared_rw_fast_pin(int fd, size_t size)
330 {
331 do_test(fd, size, TEST_TYPE_RW_FAST, true);
332 }
333
test_shared_ro_pin(int fd,size_t size)334 static void test_shared_ro_pin(int fd, size_t size)
335 {
336 do_test(fd, size, TEST_TYPE_RO, true);
337 }
338
test_shared_ro_fast_pin(int fd,size_t size)339 static void test_shared_ro_fast_pin(int fd, size_t size)
340 {
341 do_test(fd, size, TEST_TYPE_RO_FAST, true);
342 }
343
test_private_rw_pin(int fd,size_t size)344 static void test_private_rw_pin(int fd, size_t size)
345 {
346 do_test(fd, size, TEST_TYPE_RW, false);
347 }
348
test_private_rw_fast_pin(int fd,size_t size)349 static void test_private_rw_fast_pin(int fd, size_t size)
350 {
351 do_test(fd, size, TEST_TYPE_RW_FAST, false);
352 }
353
test_private_ro_pin(int fd,size_t size)354 static void test_private_ro_pin(int fd, size_t size)
355 {
356 do_test(fd, size, TEST_TYPE_RO, false);
357 }
358
test_private_ro_fast_pin(int fd,size_t size)359 static void test_private_ro_fast_pin(int fd, size_t size)
360 {
361 do_test(fd, size, TEST_TYPE_RO_FAST, false);
362 }
363
364 #ifdef LOCAL_CONFIG_HAVE_LIBURING
test_shared_iouring(int fd,size_t size)365 static void test_shared_iouring(int fd, size_t size)
366 {
367 do_test(fd, size, TEST_TYPE_IOURING, true);
368 }
369
test_private_iouring(int fd,size_t size)370 static void test_private_iouring(int fd, size_t size)
371 {
372 do_test(fd, size, TEST_TYPE_IOURING, false);
373 }
374 #endif /* LOCAL_CONFIG_HAVE_LIBURING */
375
376 static const struct test_case test_cases[] = {
377 {
378 "R/W longterm GUP pin in MAP_SHARED file mapping",
379 test_shared_rw_pin,
380 },
381 {
382 "R/W longterm GUP-fast pin in MAP_SHARED file mapping",
383 test_shared_rw_fast_pin,
384 },
385 {
386 "R/O longterm GUP pin in MAP_SHARED file mapping",
387 test_shared_ro_pin,
388 },
389 {
390 "R/O longterm GUP-fast pin in MAP_SHARED file mapping",
391 test_shared_ro_fast_pin,
392 },
393 {
394 "R/W longterm GUP pin in MAP_PRIVATE file mapping",
395 test_private_rw_pin,
396 },
397 {
398 "R/W longterm GUP-fast pin in MAP_PRIVATE file mapping",
399 test_private_rw_fast_pin,
400 },
401 {
402 "R/O longterm GUP pin in MAP_PRIVATE file mapping",
403 test_private_ro_pin,
404 },
405 {
406 "R/O longterm GUP-fast pin in MAP_PRIVATE file mapping",
407 test_private_ro_fast_pin,
408 },
409 #ifdef LOCAL_CONFIG_HAVE_LIBURING
410 {
411 "io_uring fixed buffer with MAP_SHARED file mapping",
412 test_shared_iouring,
413 },
414 {
415 "io_uring fixed buffer with MAP_PRIVATE file mapping",
416 test_private_iouring,
417 },
418 #endif /* LOCAL_CONFIG_HAVE_LIBURING */
419 };
420
run_test_case(struct test_case const * test_case)421 static void run_test_case(struct test_case const *test_case)
422 {
423 int i;
424
425 run_with_memfd(test_case->fn, test_case->desc);
426 run_with_tmpfile(test_case->fn, test_case->desc);
427 run_with_local_tmpfile(test_case->fn, test_case->desc);
428 for (i = 0; i < nr_hugetlbsizes; i++)
429 run_with_memfd_hugetlb(test_case->fn, test_case->desc,
430 hugetlbsizes[i]);
431 }
432
tests_per_test_case(void)433 static int tests_per_test_case(void)
434 {
435 return 3 + nr_hugetlbsizes;
436 }
437
main(int argc,char ** argv)438 int main(int argc, char **argv)
439 {
440 int i, err;
441
442 pagesize = getpagesize();
443 nr_hugetlbsizes = detect_hugetlb_page_sizes(hugetlbsizes,
444 ARRAY_SIZE(hugetlbsizes));
445
446 ksft_print_header();
447 ksft_set_plan(ARRAY_SIZE(test_cases) * tests_per_test_case());
448
449 gup_fd = open("/sys/kernel/debug/gup_test", O_RDWR);
450
451 for (i = 0; i < ARRAY_SIZE(test_cases); i++)
452 run_test_case(&test_cases[i]);
453
454 err = ksft_get_fail_cnt();
455 if (err)
456 ksft_exit_fail_msg("%d out of %d tests failed\n",
457 err, ksft_test_num());
458 return ksft_exit_pass();
459 }
460