1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
|
// SPDX-License-Identifier: GPL-2.0-only
/*
* Userfaultfd unit tests.
*
* Copyright (C) 2015-2023 Red Hat, Inc.
*/
#include "uffd-common.h"
#include "../../../../mm/gup_test.h"
#ifdef __NR_userfaultfd
/* The unit test doesn't need a large or random size, make it 32MB for now */
#define UFFD_TEST_MEM_SIZE (32UL << 20)
#define MEM_ANON BIT_ULL(0)
#define MEM_SHMEM BIT_ULL(1)
#define MEM_SHMEM_PRIVATE BIT_ULL(2)
#define MEM_HUGETLB BIT_ULL(3)
#define MEM_HUGETLB_PRIVATE BIT_ULL(4)
#define MEM_ALL (MEM_ANON | MEM_SHMEM | MEM_SHMEM_PRIVATE | \
MEM_HUGETLB | MEM_HUGETLB_PRIVATE)
struct mem_type {
const char *name;
unsigned int mem_flag;
uffd_test_ops_t *mem_ops;
bool shared;
};
typedef struct mem_type mem_type_t;
mem_type_t mem_types[] = {
{
.name = "anon",
.mem_flag = MEM_ANON,
.mem_ops = &anon_uffd_test_ops,
.shared = false,
},
{
.name = "shmem",
.mem_flag = MEM_SHMEM,
.mem_ops = &shmem_uffd_test_ops,
.shared = true,
},
{
.name = "shmem-private",
.mem_flag = MEM_SHMEM_PRIVATE,
.mem_ops = &shmem_uffd_test_ops,
.shared = false,
},
{
.name = "hugetlb",
.mem_flag = MEM_HUGETLB,
.mem_ops = &hugetlb_uffd_test_ops,
.shared = true,
},
{
.name = "hugetlb-private",
.mem_flag = MEM_HUGETLB_PRIVATE,
.mem_ops = &hugetlb_uffd_test_ops,
.shared = false,
},
};
/* Arguments to be passed over to each uffd unit test */
struct uffd_test_args {
mem_type_t *mem_type;
};
typedef struct uffd_test_args uffd_test_args_t;
/* Returns: UFFD_TEST_* */
typedef void (*uffd_test_fn)(uffd_test_args_t *);
typedef struct {
const char *name;
uffd_test_fn uffd_fn;
unsigned int mem_targets;
uint64_t uffd_feature_required;
} uffd_test_case_t;
static void uffd_test_report(void)
{
printf("Userfaults unit tests: pass=%u, skip=%u, fail=%u (total=%u)\n",
ksft_get_pass_cnt(),
ksft_get_xskip_cnt(),
ksft_get_fail_cnt(),
ksft_test_num());
}
static void uffd_test_pass(void)
{
printf("done\n");
ksft_inc_pass_cnt();
}
#define uffd_test_start(...) do { \
printf("Testing "); \
printf(__VA_ARGS__); \
printf("... "); \
fflush(stdout); \
} while (0)
#define uffd_test_fail(...) do { \
printf("failed [reason: "); \
printf(__VA_ARGS__); \
printf("]\n"); \
ksft_inc_fail_cnt(); \
} while (0)
static void uffd_test_skip(const char *message)
{
printf("skipped [reason: %s]\n", message);
ksft_inc_xskip_cnt();
}
/*
* Returns 1 if specific userfaultfd supported, 0 otherwise. Note, we'll
* return 1 even if some test failed as long as uffd supported, because in
* that case we still want to proceed with the rest uffd unit tests.
*/
static int test_uffd_api(bool use_dev)
{
struct uffdio_api uffdio_api;
int uffd;
uffd_test_start("UFFDIO_API (with %s)",
use_dev ? "/dev/userfaultfd" : "syscall");
if (use_dev)
uffd = uffd_open_dev(UFFD_FLAGS);
else
uffd = uffd_open_sys(UFFD_FLAGS);
if (uffd < 0) {
uffd_test_skip("cannot open userfaultfd handle");
return 0;
}
/* Test wrong UFFD_API */
uffdio_api.api = 0xab;
uffdio_api.features = 0;
if (ioctl(uffd, UFFDIO_API, &uffdio_api) == 0) {
uffd_test_fail("UFFDIO_API should fail with wrong api but didn't");
goto out;
}
/* Test wrong feature bit */
uffdio_api.api = UFFD_API;
uffdio_api.features = BIT_ULL(63);
if (ioctl(uffd, UFFDIO_API, &uffdio_api) == 0) {
uffd_test_fail("UFFDIO_API should fail with wrong feature but didn't");
goto out;
}
/* Test normal UFFDIO_API */
uffdio_api.api = UFFD_API;
uffdio_api.features = 0;
if (ioctl(uffd, UFFDIO_API, &uffdio_api)) {
uffd_test_fail("UFFDIO_API should succeed but failed");
goto out;
}
/* Test double requests of UFFDIO_API with a random feature set */
uffdio_api.features = BIT_ULL(0);
if (ioctl(uffd, UFFDIO_API, &uffdio_api) == 0) {
uffd_test_fail("UFFDIO_API should reject initialized uffd");
goto out;
}
uffd_test_pass();
out:
close(uffd);
/* We have a valid uffd handle */
return 1;
}
/*
* This function initializes the global variables. TODO: remove global
* vars and then remove this.
*/
static int
uffd_setup_environment(uffd_test_args_t *args, uffd_test_case_t *test,
mem_type_t *mem_type, const char **errmsg)
{
map_shared = mem_type->shared;
uffd_test_ops = mem_type->mem_ops;
if (mem_type->mem_flag & (MEM_HUGETLB_PRIVATE | MEM_HUGETLB))
page_size = default_huge_page_size();
else
page_size = psize();
nr_pages = UFFD_TEST_MEM_SIZE / page_size;
/* TODO: remove this global var.. it's so ugly */
nr_cpus = 1;
/* Initialize test arguments */
args->mem_type = mem_type;
return uffd_test_ctx_init(test->uffd_feature_required, errmsg);
}
static bool uffd_feature_supported(uffd_test_case_t *test)
{
uint64_t features;
if (uffd_get_features(&features))
return false;
return (features & test->uffd_feature_required) ==
test->uffd_feature_required;
}
static int pagemap_open(void)
{
int fd = open("/proc/self/pagemap", O_RDONLY);
if (fd < 0)
err("open pagemap");
return fd;
}
/* This macro let __LINE__ works in err() */
#define pagemap_check_wp(value, wp) do { \
if (!!(value & PM_UFFD_WP) != wp) \
err("pagemap uffd-wp bit error: 0x%"PRIx64, value); \
} while (0)
typedef struct {
int parent_uffd, child_uffd;
} fork_event_args;
static void *fork_event_consumer(void *data)
{
fork_event_args *args = data;
struct uffd_msg msg = { 0 };
/* Read until a full msg received */
while (uffd_read_msg(args->parent_uffd, &msg));
if (msg.event != UFFD_EVENT_FORK)
err("wrong message: %u\n", msg.event);
/* Just to be properly freed later */
args->child_uffd = msg.arg.fork.ufd;
return NULL;
}
typedef struct {
int gup_fd;
bool pinned;
} pin_args;
/*
* Returns 0 if succeed, <0 for errors. pin_pages() needs to be paired
* with unpin_pages(). Currently it needs to be RO longterm pin to satisfy
* all needs of the test cases (e.g., trigger unshare, trigger fork() early
* CoW, etc.).
*/
static int pin_pages(pin_args *args, void *buffer, size_t size)
{
struct pin_longterm_test test = {
.addr = (uintptr_t)buffer,
.size = size,
/* Read-only pins */
.flags = 0,
};
if (args->pinned)
err("already pinned");
args->gup_fd = open("/sys/kernel/debug/gup_test", O_RDWR);
if (args->gup_fd < 0)
return -errno;
if (ioctl(args->gup_fd, PIN_LONGTERM_TEST_START, &test)) {
/* Even if gup_test existed, can be an old gup_test / kernel */
close(args->gup_fd);
return -errno;
}
args->pinned = true;
return 0;
}
static void unpin_pages(pin_args *args)
{
if (!args->pinned)
err("unpin without pin first");
if (ioctl(args->gup_fd, PIN_LONGTERM_TEST_STOP))
err("PIN_LONGTERM_TEST_STOP");
close(args->gup_fd);
args->pinned = false;
}
static int pagemap_test_fork(int uffd, bool with_event, bool test_pin)
{
fork_event_args args = { .parent_uffd = uffd, .child_uffd = -1 };
pthread_t thread;
pid_t child;
uint64_t value;
int fd, result;
/* Prepare a thread to resolve EVENT_FORK */
if (with_event) {
if (pthread_create(&thread, NULL, fork_event_consumer, &args))
err("pthread_create()");
}
child = fork();
if (!child) {
/* Open the pagemap fd of the child itself */
pin_args args = {};
fd = pagemap_open();
if (test_pin && pin_pages(&args, area_dst, page_size))
/*
* Normally when reach here we have pinned in
* previous tests, so shouldn't fail anymore
*/
err("pin page failed in child");
value = pagemap_get_entry(fd, area_dst);
/*
* After fork(), we should handle uffd-wp bit differently:
*
* (1) when with EVENT_FORK, it should persist
* (2) when without EVENT_FORK, it should be dropped
*/
pagemap_check_wp(value, with_event);
if (test_pin)
unpin_pages(&args);
/* Succeed */
exit(0);
}
waitpid(child, &result, 0);
if (with_event) {
if (pthread_join(thread, NULL))
err("pthread_join()");
if (args.child_uffd < 0)
err("Didn't receive child uffd");
close(args.child_uffd);
}
return result;
}
static void uffd_wp_unpopulated_test(uffd_test_args_t *args)
{
uint64_t value;
int pagemap_fd;
if (uffd_register(uffd, area_dst, nr_pages * page_size,
false, true, false))
err("register failed");
pagemap_fd = pagemap_open();
/* Test applying pte marker to anon unpopulated */
wp_range(uffd, (uint64_t)area_dst, page_size, true);
value = pagemap_get_entry(pagemap_fd, area_dst);
pagemap_check_wp(value, true);
/* Test unprotect on anon pte marker */
wp_range(uffd, (uint64_t)area_dst, page_size, false);
value = pagemap_get_entry(pagemap_fd, area_dst);
pagemap_check_wp(value, false);
/* Test zap on anon marker */
wp_range(uffd, (uint64_t)area_dst, page_size, true);
if (madvise(area_dst, page_size, MADV_DONTNEED))
err("madvise(MADV_DONTNEED) failed");
value = pagemap_get_entry(pagemap_fd, area_dst);
pagemap_check_wp(value, false);
/* Test fault in after marker removed */
*area_dst = 1;
value = pagemap_get_entry(pagemap_fd, area_dst);
pagemap_check_wp(value, false);
/* Drop it to make pte none again */
if (madvise(area_dst, page_size, MADV_DONTNEED))
err("madvise(MADV_DONTNEED) failed");
/* Test read-zero-page upon pte marker */
wp_range(uffd, (uint64_t)area_dst, page_size, true);
*(volatile char *)area_dst;
/* Drop it to make pte none again */
if (madvise(area_dst, page_size, MADV_DONTNEED))
err("madvise(MADV_DONTNEED) failed");
uffd_test_pass();
}
static void uffd_wp_fork_test_common(uffd_test_args_t *args,
bool with_event)
{
int pagemap_fd;
uint64_t value;
if (uffd_register(uffd, area_dst, nr_pages * page_size,
false, true, false))
err("register failed");
pagemap_fd = pagemap_open();
/* Touch the page */
*area_dst = 1;
wp_range(uffd, (uint64_t)area_dst, page_size, true);
value = pagemap_get_entry(pagemap_fd, area_dst);
pagemap_check_wp(value, true);
if (pagemap_test_fork(uffd, with_event, false)) {
uffd_test_fail("Detected %s uffd-wp bit in child in present pte",
with_event ? "missing" : "stall");
goto out;
}
/*
* This is an attempt for zapping the pgtable so as to test the
* markers.
*
* For private mappings, PAGEOUT will only work on exclusive ptes
* (PM_MMAP_EXCLUSIVE) which we should satisfy.
*
* For shared, PAGEOUT may not work. Use DONTNEED instead which
* plays a similar role of zapping (rather than freeing the page)
* to expose pte markers.
*/
if (args->mem_type->shared) {
if (madvise(area_dst, page_size, MADV_DONTNEED))
err("MADV_DONTNEED");
} else {
/*
* NOTE: ignore retval because private-hugetlb doesn't yet
* support swapping, so it could fail.
*/
madvise(area_dst, page_size, MADV_PAGEOUT);
}
/* Uffd-wp should persist even swapped out */
value = pagemap_get_entry(pagemap_fd, area_dst);
pagemap_check_wp(value, true);
if (pagemap_test_fork(uffd, with_event, false)) {
uffd_test_fail("Detected %s uffd-wp bit in child in zapped pte",
with_event ? "missing" : "stall");
goto out;
}
/* Unprotect; this tests swap pte modifications */
wp_range(uffd, (uint64_t)area_dst, page_size, false);
value = pagemap_get_entry(pagemap_fd, area_dst);
pagemap_check_wp(value, false);
/* Fault in the page from disk */
*area_dst = 2;
value = pagemap_get_entry(pagemap_fd, area_dst);
pagemap_check_wp(value, false);
uffd_test_pass();
out:
if (uffd_unregister(uffd, area_dst, nr_pages * page_size))
err("unregister failed");
close(pagemap_fd);
}
static void uffd_wp_fork_test(uffd_test_args_t *args)
{
uffd_wp_fork_test_common(args, false);
}
static void uffd_wp_fork_with_event_test(uffd_test_args_t *args)
{
uffd_wp_fork_test_common(args, true);
}
static void uffd_wp_fork_pin_test_common(uffd_test_args_t *args,
bool with_event)
{
int pagemap_fd;
pin_args pin_args = {};
if (uffd_register(uffd, area_dst, page_size, false, true, false))
err("register failed");
pagemap_fd = pagemap_open();
/* Touch the page */
*area_dst = 1;
wp_range(uffd, (uint64_t)area_dst, page_size, true);
/*
* 1. First pin, then fork(). This tests fork() special path when
* doing early CoW if the page is private.
*/
if (pin_pages(&pin_args, area_dst, page_size)) {
uffd_test_skip("Possibly CONFIG_GUP_TEST missing "
"or unprivileged");
close(pagemap_fd);
uffd_unregister(uffd, area_dst, page_size);
return;
}
if (pagemap_test_fork(uffd, with_event, false)) {
uffd_test_fail("Detected %s uffd-wp bit in early CoW of fork()",
with_event ? "missing" : "stall");
unpin_pages(&pin_args);
goto out;
}
unpin_pages(&pin_args);
/*
* 2. First fork(), then pin (in the child, where test_pin==true).
* This tests COR, aka, page unsharing on private memories.
*/
if (pagemap_test_fork(uffd, with_event, true)) {
uffd_test_fail("Detected %s uffd-wp bit when RO pin",
with_event ? "missing" : "stall");
goto out;
}
uffd_test_pass();
out:
if (uffd_unregister(uffd, area_dst, page_size))
err("register failed");
close(pagemap_fd);
}
static void uffd_wp_fork_pin_test(uffd_test_args_t *args)
{
uffd_wp_fork_pin_test_common(args, false);
}
static void uffd_wp_fork_pin_with_event_test(uffd_test_args_t *args)
{
uffd_wp_fork_pin_test_common(args, true);
}
static void check_memory_contents(char *p)
{
unsigned long i, j;
uint8_t expected_byte;
for (i = 0; i < nr_pages; ++i) {
expected_byte = ~((uint8_t)(i % ((uint8_t)-1)));
for (j = 0; j < page_size; j++) {
uint8_t v = *(uint8_t *)(p + (i * page_size) + j);
if (v != expected_byte)
err("unexpected page contents");
}
}
}
static void uffd_minor_test_common(bool test_collapse, bool test_wp)
{
unsigned long p;
pthread_t uffd_mon;
char c;
struct uffd_args args = { 0 };
/*
* NOTE: MADV_COLLAPSE is not yet compatible with WP, so testing
* both do not make much sense.
*/
assert(!(test_collapse && test_wp));
if (uffd_register(uffd, area_dst_alias, nr_pages * page_size,
/* NOTE! MADV_COLLAPSE may not work with uffd-wp */
false, test_wp, true))
err("register failure");
/*
* After registering with UFFD, populate the non-UFFD-registered side of
* the shared mapping. This should *not* trigger any UFFD minor faults.
*/
for (p = 0; p < nr_pages; ++p)
memset(area_dst + (p * page_size), p % ((uint8_t)-1),
page_size);
args.apply_wp = test_wp;
if (pthread_create(&uffd_mon, NULL, uffd_poll_thread, &args))
err("uffd_poll_thread create");
/*
* Read each of the pages back using the UFFD-registered mapping. We
* expect that the first time we touch a page, it will result in a minor
* fault. uffd_poll_thread will resolve the fault by bit-flipping the
* page's contents, and then issuing a CONTINUE ioctl.
*/
check_memory_contents(area_dst_alias);
if (write(pipefd[1], &c, sizeof(c)) != sizeof(c))
err("pipe write");
if (pthread_join(uffd_mon, NULL))
err("join() failed");
if (test_collapse) {
if (madvise(area_dst_alias, nr_pages * page_size,
MADV_COLLAPSE)) {
/* It's fine to fail for this one... */
uffd_test_skip("MADV_COLLAPSE failed");
return;
}
uffd_test_ops->check_pmd_mapping(area_dst,
nr_pages * page_size /
read_pmd_pagesize());
/*
* This won't cause uffd-fault - it purely just makes sure there
* was no corruption.
*/
check_memory_contents(area_dst_alias);
}
if (args.missing_faults != 0 || args.minor_faults != nr_pages)
uffd_test_fail("stats check error");
else
uffd_test_pass();
}
void uffd_minor_test(uffd_test_args_t *args)
{
uffd_minor_test_common(false, false);
}
void uffd_minor_wp_test(uffd_test_args_t *args)
{
uffd_minor_test_common(false, true);
}
void uffd_minor_collapse_test(uffd_test_args_t *args)
{
uffd_minor_test_common(true, false);
}
static sigjmp_buf jbuf, *sigbuf;
static void sighndl(int sig, siginfo_t *siginfo, void *ptr)
{
if (sig == SIGBUS) {
if (sigbuf)
siglongjmp(*sigbuf, 1);
abort();
}
}
/*
* For non-cooperative userfaultfd test we fork() a process that will
* generate pagefaults, will mremap the area monitored by the
* userfaultfd and at last this process will release the monitored
* area.
* For the anonymous and shared memory the area is divided into two
* parts, the first part is accessed before mremap, and the second
* part is accessed after mremap. Since hugetlbfs does not support
* mremap, the entire monitored area is accessed in a single pass for
* HUGETLB_TEST.
* The release of the pages currently generates event for shmem and
* anonymous memory (UFFD_EVENT_REMOVE), hence it is not checked
* for hugetlb.
* For signal test(UFFD_FEATURE_SIGBUS), signal_test = 1, we register
* monitored area, generate pagefaults and test that signal is delivered.
* Use UFFDIO_COPY to allocate missing page and retry. For signal_test = 2
* test robustness use case - we release monitored area, fork a process
* that will generate pagefaults and verify signal is generated.
* This also tests UFFD_FEATURE_EVENT_FORK event along with the signal
* feature. Using monitor thread, verify no userfault events are generated.
*/
static int faulting_process(int signal_test, bool wp)
{
unsigned long nr, i;
unsigned long long count;
unsigned long split_nr_pages;
unsigned long lastnr;
struct sigaction act;
volatile unsigned long signalled = 0;
split_nr_pages = (nr_pages + 1) / 2;
if (signal_test) {
sigbuf = &jbuf;
memset(&act, 0, sizeof(act));
act.sa_sigaction = sighndl;
act.sa_flags = SA_SIGINFO;
if (sigaction(SIGBUS, &act, 0))
err("sigaction");
lastnr = (unsigned long)-1;
}
for (nr = 0; nr < split_nr_pages; nr++) {
volatile int steps = 1;
unsigned long offset = nr * page_size;
if (signal_test) {
if (sigsetjmp(*sigbuf, 1) != 0) {
if (steps == 1 && nr == lastnr)
err("Signal repeated");
lastnr = nr;
if (signal_test == 1) {
if (steps == 1) {
/* This is a MISSING request */
steps++;
if (copy_page(uffd, offset, wp))
signalled++;
} else {
/* This is a WP request */
assert(steps == 2);
wp_range(uffd,
(__u64)area_dst +
offset,
page_size, false);
}
} else {
signalled++;
continue;
}
}
}
count = *area_count(area_dst, nr);
if (count != count_verify[nr])
err("nr %lu memory corruption %llu %llu\n",
nr, count, count_verify[nr]);
/*
* Trigger write protection if there is by writing
* the same value back.
*/
*area_count(area_dst, nr) = count;
}
if (signal_test)
return signalled != split_nr_pages;
area_dst = mremap(area_dst, nr_pages * page_size, nr_pages * page_size,
MREMAP_MAYMOVE | MREMAP_FIXED, area_src);
if (area_dst == MAP_FAILED)
err("mremap");
/* Reset area_src since we just clobbered it */
area_src = NULL;
for (; nr < nr_pages; nr++) {
count = *area_count(area_dst, nr);
if (count != count_verify[nr]) {
err("nr %lu memory corruption %llu %llu\n",
nr, count, count_verify[nr]);
}
/*
* Trigger write protection if there is by writing
* the same value back.
*/
*area_count(area_dst, nr) = count;
}
uffd_test_ops->release_pages(area_dst);
for (nr = 0; nr < nr_pages; nr++)
for (i = 0; i < page_size; i++)
if (*(area_dst + nr * page_size + i) != 0)
err("page %lu offset %lu is not zero", nr, i);
return 0;
}
static void uffd_sigbus_test_common(bool wp)
{
unsigned long userfaults;
pthread_t uffd_mon;
pid_t pid;
int err;
char c;
struct uffd_args args = { 0 };
fcntl(uffd, F_SETFL, uffd_flags | O_NONBLOCK);
if (uffd_register(uffd, area_dst, nr_pages * page_size,
true, wp, false))
err("register failure");
if (faulting_process(1, wp))
err("faulting process failed");
uffd_test_ops->release_pages(area_dst);
args.apply_wp = wp;
if (pthread_create(&uffd_mon, NULL, uffd_poll_thread, &args))
err("uffd_poll_thread create");
pid = fork();
if (pid < 0)
err("fork");
if (!pid)
exit(faulting_process(2, wp));
waitpid(pid, &err, 0);
if (err)
err("faulting process failed");
if (write(pipefd[1], &c, sizeof(c)) != sizeof(c))
err("pipe write");
if (pthread_join(uffd_mon, (void **)&userfaults))
err("pthread_join()");
if (userfaults)
uffd_test_fail("Signal test failed, userfaults: %ld", userfaults);
else
uffd_test_pass();
}
static void uffd_sigbus_test(uffd_test_args_t *args)
{
uffd_sigbus_test_common(false);
}
static void uffd_sigbus_wp_test(uffd_test_args_t *args)
{
uffd_sigbus_test_common(true);
}
static void uffd_events_test_common(bool wp)
{
pthread_t uffd_mon;
pid_t pid;
int err;
char c;
struct uffd_args args = { 0 };
fcntl(uffd, F_SETFL, uffd_flags | O_NONBLOCK);
if (uffd_register(uffd, area_dst, nr_pages * page_size,
true, wp, false))
err("register failure");
args.apply_wp = wp;
if (pthread_create(&uffd_mon, NULL, uffd_poll_thread, &args))
err("uffd_poll_thread create");
pid = fork();
if (pid < 0)
err("fork");
if (!pid)
exit(faulting_process(0, wp));
waitpid(pid, &err, 0);
if (err)
err("faulting process failed");
if (write(pipefd[1], &c, sizeof(c)) != sizeof(c))
err("pipe write");
if (pthread_join(uffd_mon, NULL))
err("pthread_join()");
if (args.missing_faults != nr_pages)
uffd_test_fail("Fault counts wrong");
else
uffd_test_pass();
}
static void uffd_events_test(uffd_test_args_t *args)
{
uffd_events_test_common(false);
}
static void uffd_events_wp_test(uffd_test_args_t *args)
{
uffd_events_test_common(true);
}
static void retry_uffdio_zeropage(int ufd,
struct uffdio_zeropage *uffdio_zeropage)
{
uffd_test_ops->alias_mapping(&uffdio_zeropage->range.start,
uffdio_zeropage->range.len,
0);
if (ioctl(ufd, UFFDIO_ZEROPAGE, uffdio_zeropage)) {
if (uffdio_zeropage->zeropage != -EEXIST)
err("UFFDIO_ZEROPAGE error: %"PRId64,
(int64_t)uffdio_zeropage->zeropage);
} else {
err("UFFDIO_ZEROPAGE error: %"PRId64,
(int64_t)uffdio_zeropage->zeropage);
}
}
static bool do_uffdio_zeropage(int ufd, bool has_zeropage)
{
struct uffdio_zeropage uffdio_zeropage = { 0 };
int ret;
__s64 res;
uffdio_zeropage.range.start = (unsigned long) area_dst;
uffdio_zeropage.range.len = page_size;
uffdio_zeropage.mode = 0;
ret = ioctl(ufd, UFFDIO_ZEROPAGE, &uffdio_zeropage);
res = uffdio_zeropage.zeropage;
if (ret) {
/* real retval in ufdio_zeropage.zeropage */
if (has_zeropage)
err("UFFDIO_ZEROPAGE error: %"PRId64, (int64_t)res);
else if (res != -EINVAL)
err("UFFDIO_ZEROPAGE not -EINVAL");
} else if (has_zeropage) {
if (res != page_size)
err("UFFDIO_ZEROPAGE unexpected size");
else
retry_uffdio_zeropage(ufd, &uffdio_zeropage);
return true;
} else
err("UFFDIO_ZEROPAGE succeeded");
return false;
}
/*
* Registers a range with MISSING mode only for zeropage test. Return true
* if UFFDIO_ZEROPAGE supported, false otherwise. Can't use uffd_register()
* because we want to detect .ioctls along the way.
*/
static bool
uffd_register_detect_zeropage(int uffd, void *addr, uint64_t len)
{
uint64_t ioctls = 0;
if (uffd_register_with_ioctls(uffd, addr, len, true,
false, false, &ioctls))
err("zeropage register fail");
return ioctls & (1 << _UFFDIO_ZEROPAGE);
}
/* exercise UFFDIO_ZEROPAGE */
static void uffd_zeropage_test(uffd_test_args_t *args)
{
bool has_zeropage;
int i;
has_zeropage = uffd_register_detect_zeropage(uffd, area_dst, page_size);
if (area_dst_alias)
/* Ignore the retval; we already have it */
uffd_register_detect_zeropage(uffd, area_dst_alias, page_size);
if (do_uffdio_zeropage(uffd, has_zeropage))
for (i = 0; i < page_size; i++)
if (area_dst[i] != 0)
err("data non-zero at offset %d\n", i);
if (uffd_unregister(uffd, area_dst, page_size))
err("unregister");
if (area_dst_alias && uffd_unregister(uffd, area_dst_alias, page_size))
err("unregister");
uffd_test_pass();
}
static void uffd_register_poison(int uffd, void *addr, uint64_t len)
{
uint64_t ioctls = 0;
uint64_t expected = (1 << _UFFDIO_COPY) | (1 << _UFFDIO_POISON);
if (uffd_register_with_ioctls(uffd, addr, len, true,
false, false, &ioctls))
err("poison register fail");
if ((ioctls & expected) != expected)
err("registered area doesn't support COPY and POISON ioctls");
}
static void do_uffdio_poison(int uffd, unsigned long offset)
{
struct uffdio_poison uffdio_poison = { 0 };
int ret;
__s64 res;
uffdio_poison.range.start = (unsigned long) area_dst + offset;
uffdio_poison.range.len = page_size;
uffdio_poison.mode = 0;
ret = ioctl(uffd, UFFDIO_POISON, &uffdio_poison);
res = uffdio_poison.updated;
if (ret)
err("UFFDIO_POISON error: %"PRId64, (int64_t)res);
else if (res != page_size)
err("UFFDIO_POISON unexpected size: %"PRId64, (int64_t)res);
}
static void uffd_poison_handle_fault(
struct uffd_msg *msg, struct uffd_args *args)
{
unsigned long offset;
if (msg->event != UFFD_EVENT_PAGEFAULT)
err("unexpected msg event %u", msg->event);
if (msg->arg.pagefault.flags &
(UFFD_PAGEFAULT_FLAG_WP | UFFD_PAGEFAULT_FLAG_MINOR))
err("unexpected fault type %llu", msg->arg.pagefault.flags);
offset = (char *)(unsigned long)msg->arg.pagefault.address - area_dst;
offset &= ~(page_size-1);
/* Odd pages -> copy zeroed page; even pages -> poison. */
if (offset & page_size)
copy_page(uffd, offset, false);
else
do_uffdio_poison(uffd, offset);
}
static void uffd_poison_test(uffd_test_args_t *targs)
{
pthread_t uffd_mon;
char c;
struct uffd_args args = { 0 };
struct sigaction act = { 0 };
unsigned long nr_sigbus = 0;
unsigned long nr;
fcntl(uffd, F_SETFL, uffd_flags | O_NONBLOCK);
uffd_register_poison(uffd, area_dst, nr_pages * page_size);
memset(area_src, 0, nr_pages * page_size);
args.handle_fault = uffd_poison_handle_fault;
if (pthread_create(&uffd_mon, NULL, uffd_poll_thread, &args))
err("uffd_poll_thread create");
sigbuf = &jbuf;
act.sa_sigaction = sighndl;
act.sa_flags = SA_SIGINFO;
if (sigaction(SIGBUS, &act, 0))
err("sigaction");
for (nr = 0; nr < nr_pages; ++nr) {
unsigned long offset = nr * page_size;
const char *bytes = (const char *) area_dst + offset;
const char *i;
if (sigsetjmp(*sigbuf, 1)) {
/*
* Access below triggered a SIGBUS, which was caught by
* sighndl, which then jumped here. Count this SIGBUS,
* and move on to next page.
*/
++nr_sigbus;
continue;
}
for (i = bytes; i < bytes + page_size; ++i) {
if (*i)
err("nonzero byte in area_dst (%p) at %p: %u",
area_dst, i, *i);
}
}
if (write(pipefd[1], &c, sizeof(c)) != sizeof(c))
err("pipe write");
if (pthread_join(uffd_mon, NULL))
err("pthread_join()");
if (nr_sigbus != nr_pages / 2)
err("expected to receive %lu SIGBUS, actually received %lu",
nr_pages / 2, nr_sigbus);
uffd_test_pass();
}
/*
* Test the returned uffdio_register.ioctls with different register modes.
* Note that _UFFDIO_ZEROPAGE is tested separately in the zeropage test.
*/
static void
do_register_ioctls_test(uffd_test_args_t *args, bool miss, bool wp, bool minor)
{
uint64_t ioctls = 0, expected = BIT_ULL(_UFFDIO_WAKE);
mem_type_t *mem_type = args->mem_type;
int ret;
ret = uffd_register_with_ioctls(uffd, area_dst, page_size,
miss, wp, minor, &ioctls);
/*
* Handle special cases of UFFDIO_REGISTER here where it should
* just fail with -EINVAL first..
*
* Case 1: register MINOR on anon
* Case 2: register with no mode selected
*/
if ((minor && (mem_type->mem_flag == MEM_ANON)) ||
(!miss && !wp && !minor)) {
if (ret != -EINVAL)
err("register (miss=%d, wp=%d, minor=%d) failed "
"with wrong errno=%d", miss, wp, minor, ret);
return;
}
/* UFFDIO_REGISTER should succeed, then check ioctls returned */
if (miss)
expected |= BIT_ULL(_UFFDIO_COPY);
if (wp)
expected |= BIT_ULL(_UFFDIO_WRITEPROTECT);
if (minor)
expected |= BIT_ULL(_UFFDIO_CONTINUE);
if ((ioctls & expected) != expected)
err("unexpected uffdio_register.ioctls "
"(miss=%d, wp=%d, minor=%d): expected=0x%"PRIx64", "
"returned=0x%"PRIx64, miss, wp, minor, expected, ioctls);
if (uffd_unregister(uffd, area_dst, page_size))
err("unregister");
}
static void uffd_register_ioctls_test(uffd_test_args_t *args)
{
int miss, wp, minor;
for (miss = 0; miss <= 1; miss++)
for (wp = 0; wp <= 1; wp++)
for (minor = 0; minor <= 1; minor++)
do_register_ioctls_test(args, miss, wp, minor);
uffd_test_pass();
}
uffd_test_case_t uffd_tests[] = {
{
/* Test returned uffdio_register.ioctls. */
.name = "register-ioctls",
.uffd_fn = uffd_register_ioctls_test,
.mem_targets = MEM_ALL,
.uffd_feature_required = UFFD_FEATURE_MISSING_HUGETLBFS |
UFFD_FEATURE_MISSING_SHMEM |
UFFD_FEATURE_PAGEFAULT_FLAG_WP |
UFFD_FEATURE_WP_HUGETLBFS_SHMEM |
UFFD_FEATURE_MINOR_HUGETLBFS |
UFFD_FEATURE_MINOR_SHMEM,
},
{
.name = "zeropage",
.uffd_fn = uffd_zeropage_test,
.mem_targets = MEM_ALL,
.uffd_feature_required = 0,
},
{
.name = "wp-fork",
.uffd_fn = uffd_wp_fork_test,
.mem_targets = MEM_ALL,
.uffd_feature_required = UFFD_FEATURE_PAGEFAULT_FLAG_WP |
UFFD_FEATURE_WP_HUGETLBFS_SHMEM,
},
{
.name = "wp-fork-with-event",
.uffd_fn = uffd_wp_fork_with_event_test,
.mem_targets = MEM_ALL,
.uffd_feature_required = UFFD_FEATURE_PAGEFAULT_FLAG_WP |
UFFD_FEATURE_WP_HUGETLBFS_SHMEM |
/* when set, child process should inherit uffd-wp bits */
UFFD_FEATURE_EVENT_FORK,
},
{
.name = "wp-fork-pin",
.uffd_fn = uffd_wp_fork_pin_test,
.mem_targets = MEM_ALL,
.uffd_feature_required = UFFD_FEATURE_PAGEFAULT_FLAG_WP |
UFFD_FEATURE_WP_HUGETLBFS_SHMEM,
},
{
.name = "wp-fork-pin-with-event",
.uffd_fn = uffd_wp_fork_pin_with_event_test,
.mem_targets = MEM_ALL,
.uffd_feature_required = UFFD_FEATURE_PAGEFAULT_FLAG_WP |
UFFD_FEATURE_WP_HUGETLBFS_SHMEM |
/* when set, child process should inherit uffd-wp bits */
UFFD_FEATURE_EVENT_FORK,
},
{
.name = "wp-unpopulated",
.uffd_fn = uffd_wp_unpopulated_test,
.mem_targets = MEM_ANON,
.uffd_feature_required =
UFFD_FEATURE_PAGEFAULT_FLAG_WP | UFFD_FEATURE_WP_UNPOPULATED,
},
{
.name = "minor",
.uffd_fn = uffd_minor_test,
.mem_targets = MEM_SHMEM | MEM_HUGETLB,
.uffd_feature_required =
UFFD_FEATURE_MINOR_HUGETLBFS | UFFD_FEATURE_MINOR_SHMEM,
},
{
.name = "minor-wp",
.uffd_fn = uffd_minor_wp_test,
.mem_targets = MEM_SHMEM | MEM_HUGETLB,
.uffd_feature_required =
UFFD_FEATURE_MINOR_HUGETLBFS | UFFD_FEATURE_MINOR_SHMEM |
UFFD_FEATURE_PAGEFAULT_FLAG_WP |
/*
* HACK: here we leveraged WP_UNPOPULATED to detect whether
* minor mode supports wr-protect. There's no feature flag
* for it so this is the best we can test against.
*/
UFFD_FEATURE_WP_UNPOPULATED,
},
{
.name = "minor-collapse",
.uffd_fn = uffd_minor_collapse_test,
/* MADV_COLLAPSE only works with shmem */
.mem_targets = MEM_SHMEM,
/* We can't test MADV_COLLAPSE, so try our luck */
.uffd_feature_required = UFFD_FEATURE_MINOR_SHMEM,
},
{
.name = "sigbus",
.uffd_fn = uffd_sigbus_test,
.mem_targets = MEM_ALL,
.uffd_feature_required = UFFD_FEATURE_SIGBUS |
UFFD_FEATURE_EVENT_FORK,
},
{
.name = "sigbus-wp",
.uffd_fn = uffd_sigbus_wp_test,
.mem_targets = MEM_ALL,
.uffd_feature_required = UFFD_FEATURE_SIGBUS |
UFFD_FEATURE_EVENT_FORK | UFFD_FEATURE_PAGEFAULT_FLAG_WP,
},
{
.name = "events",
.uffd_fn = uffd_events_test,
.mem_targets = MEM_ALL,
.uffd_feature_required = UFFD_FEATURE_EVENT_FORK |
UFFD_FEATURE_EVENT_REMAP | UFFD_FEATURE_EVENT_REMOVE,
},
{
.name = "events-wp",
.uffd_fn = uffd_events_wp_test,
.mem_targets = MEM_ALL,
.uffd_feature_required = UFFD_FEATURE_EVENT_FORK |
UFFD_FEATURE_EVENT_REMAP | UFFD_FEATURE_EVENT_REMOVE |
UFFD_FEATURE_PAGEFAULT_FLAG_WP |
UFFD_FEATURE_WP_HUGETLBFS_SHMEM,
},
{
.name = "poison",
.uffd_fn = uffd_poison_test,
.mem_targets = MEM_ALL,
.uffd_feature_required = UFFD_FEATURE_POISON,
},
};
static void usage(const char *prog)
{
printf("usage: %s [-f TESTNAME]\n", prog);
puts("");
puts(" -f: test name to filter (e.g., event)");
puts(" -h: show the help msg");
puts(" -l: list tests only");
puts("");
exit(KSFT_FAIL);
}
int main(int argc, char *argv[])
{
int n_tests = sizeof(uffd_tests) / sizeof(uffd_test_case_t);
int n_mems = sizeof(mem_types) / sizeof(mem_type_t);
const char *test_filter = NULL;
bool list_only = false;
uffd_test_case_t *test;
mem_type_t *mem_type;
uffd_test_args_t args;
const char *errmsg;
int has_uffd, opt;
int i, j;
while ((opt = getopt(argc, argv, "f:hl")) != -1) {
switch (opt) {
case 'f':
test_filter = optarg;
break;
case 'l':
list_only = true;
break;
case 'h':
default:
/* Unknown */
usage(argv[0]);
break;
}
}
if (!test_filter && !list_only) {
has_uffd = test_uffd_api(false);
has_uffd |= test_uffd_api(true);
if (!has_uffd) {
printf("Userfaultfd not supported or unprivileged, skip all tests\n");
exit(KSFT_SKIP);
}
}
for (i = 0; i < n_tests; i++) {
test = &uffd_tests[i];
if (test_filter && !strstr(test->name, test_filter))
continue;
if (list_only) {
printf("%s\n", test->name);
continue;
}
for (j = 0; j < n_mems; j++) {
mem_type = &mem_types[j];
if (!(test->mem_targets & mem_type->mem_flag))
continue;
uffd_test_start("%s on %s", test->name, mem_type->name);
if (!uffd_feature_supported(test)) {
uffd_test_skip("feature missing");
continue;
}
if (uffd_setup_environment(&args, test, mem_type,
&errmsg)) {
uffd_test_skip(errmsg);
continue;
}
test->uffd_fn(&args);
uffd_test_ctx_clear();
}
}
if (!list_only)
uffd_test_report();
return ksft_get_fail_cnt() ? KSFT_FAIL : KSFT_PASS;
}
#else /* __NR_userfaultfd */
#warning "missing __NR_userfaultfd definition"
int main(void)
{
printf("Skipping %s (missing __NR_userfaultfd)\n", __file__);
return KSFT_SKIP;
}
#endif /* __NR_userfaultfd */
|