summaryrefslogtreecommitdiffstats
path: root/drivers/s390/virtio/virtio_ccw.c
blob: 97e51c34e6cfbb3f9858da695a28e57378f4b776 (plain)
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
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
// SPDX-License-Identifier: GPL-2.0
/*
 * ccw based virtio transport
 *
 * Copyright IBM Corp. 2012, 2014
 *
 *    Author(s): Cornelia Huck <cornelia.huck@de.ibm.com>
 */

#include <linux/kernel_stat.h>
#include <linux/init.h>
#include <linux/memblock.h>
#include <linux/err.h>
#include <linux/virtio.h>
#include <linux/virtio_config.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/virtio_ring.h>
#include <linux/pfn.h>
#include <linux/async.h>
#include <linux/wait.h>
#include <linux/list.h>
#include <linux/bitops.h>
#include <linux/moduleparam.h>
#include <linux/io.h>
#include <linux/kvm_para.h>
#include <linux/notifier.h>
#include <asm/diag.h>
#include <asm/setup.h>
#include <asm/irq.h>
#include <asm/cio.h>
#include <asm/ccwdev.h>
#include <asm/virtio-ccw.h>
#include <asm/isc.h>
#include <asm/airq.h>

/*
 * virtio related functions
 */

struct vq_config_block {
	__u16 index;
	__u16 num;
} __packed;

#define VIRTIO_CCW_CONFIG_SIZE 0x100
/* same as PCI config space size, should be enough for all drivers */

struct vcdev_dma_area {
	unsigned long indicators;
	unsigned long indicators2;
	struct vq_config_block config_block;
	__u8 status;
};

struct virtio_ccw_device {
	struct virtio_device vdev;
	__u8 config[VIRTIO_CCW_CONFIG_SIZE];
	struct ccw_device *cdev;
	__u32 curr_io;
	int err;
	unsigned int revision; /* Transport revision */
	wait_queue_head_t wait_q;
	spinlock_t lock;
	rwlock_t irq_lock;
	struct mutex io_lock; /* Serializes I/O requests */
	struct list_head virtqueues;
	bool is_thinint;
	bool going_away;
	bool device_lost;
	unsigned int config_ready;
	void *airq_info;
	struct vcdev_dma_area *dma_area;
};

static inline unsigned long *indicators(struct virtio_ccw_device *vcdev)
{
	return &vcdev->dma_area->indicators;
}

static inline unsigned long *indicators2(struct virtio_ccw_device *vcdev)
{
	return &vcdev->dma_area->indicators2;
}

struct vq_info_block_legacy {
	__u64 queue;
	__u32 align;
	__u16 index;
	__u16 num;
} __packed;

struct vq_info_block {
	__u64 desc;
	__u32 res0;
	__u16 index;
	__u16 num;
	__u64 avail;
	__u64 used;
} __packed;

struct virtio_feature_desc {
	__le32 features;
	__u8 index;
} __packed;

struct virtio_thinint_area {
	unsigned long summary_indicator;
	unsigned long indicator;
	u64 bit_nr;
	u8 isc;
} __packed;

struct virtio_rev_info {
	__u16 revision;
	__u16 length;
	__u8 data[];
};

/* the highest virtio-ccw revision we support */
#define VIRTIO_CCW_REV_MAX 2

struct virtio_ccw_vq_info {
	struct virtqueue *vq;
	int num;
	union {
		struct vq_info_block s;
		struct vq_info_block_legacy l;
	} *info_block;
	int bit_nr;
	struct list_head node;
	long cookie;
};

#define VIRTIO_AIRQ_ISC IO_SCH_ISC /* inherit from subchannel */

#define VIRTIO_IV_BITS (L1_CACHE_BYTES * 8)
#define MAX_AIRQ_AREAS 20

static int virtio_ccw_use_airq = 1;

struct airq_info {
	rwlock_t lock;
	u8 summary_indicator_idx;
	struct airq_struct airq;
	struct airq_iv *aiv;
};
static struct airq_info *airq_areas[MAX_AIRQ_AREAS];
static DEFINE_MUTEX(airq_areas_lock);

static u8 *summary_indicators;

static inline u8 *get_summary_indicator(struct airq_info *info)
{
	return summary_indicators + info->summary_indicator_idx;
}

#define CCW_CMD_SET_VQ 0x13
#define CCW_CMD_VDEV_RESET 0x33
#define CCW_CMD_SET_IND 0x43
#define CCW_CMD_SET_CONF_IND 0x53
#define CCW_CMD_READ_FEAT 0x12
#define CCW_CMD_WRITE_FEAT 0x11
#define CCW_CMD_READ_CONF 0x22
#define CCW_CMD_WRITE_CONF 0x21
#define CCW_CMD_WRITE_STATUS 0x31
#define CCW_CMD_READ_VQ_CONF 0x32
#define CCW_CMD_READ_STATUS 0x72
#define CCW_CMD_SET_IND_ADAPTER 0x73
#define CCW_CMD_SET_VIRTIO_REV 0x83

#define VIRTIO_CCW_DOING_SET_VQ 0x00010000
#define VIRTIO_CCW_DOING_RESET 0x00040000
#define VIRTIO_CCW_DOING_READ_FEAT 0x00080000
#define VIRTIO_CCW_DOING_WRITE_FEAT 0x00100000
#define VIRTIO_CCW_DOING_READ_CONFIG 0x00200000
#define VIRTIO_CCW_DOING_WRITE_CONFIG 0x00400000
#define VIRTIO_CCW_DOING_WRITE_STATUS 0x00800000
#define VIRTIO_CCW_DOING_SET_IND 0x01000000
#define VIRTIO_CCW_DOING_READ_VQ_CONF 0x02000000
#define VIRTIO_CCW_DOING_SET_CONF_IND 0x04000000
#define VIRTIO_CCW_DOING_SET_IND_ADAPTER 0x08000000
#define VIRTIO_CCW_DOING_SET_VIRTIO_REV 0x10000000
#define VIRTIO_CCW_DOING_READ_STATUS 0x20000000
#define VIRTIO_CCW_INTPARM_MASK 0xffff0000

static struct virtio_ccw_device *to_vc_device(struct virtio_device *vdev)
{
	return container_of(vdev, struct virtio_ccw_device, vdev);
}

static void drop_airq_indicator(struct virtqueue *vq, struct airq_info *info)
{
	unsigned long i, flags;

	write_lock_irqsave(&info->lock, flags);
	for (i = 0; i < airq_iv_end(info->aiv); i++) {
		if (vq == (void *)airq_iv_get_ptr(info->aiv, i)) {
			airq_iv_free_bit(info->aiv, i);
			airq_iv_set_ptr(info->aiv, i, 0);
			break;
		}
	}
	write_unlock_irqrestore(&info->lock, flags);
}

static void virtio_airq_handler(struct airq_struct *airq, bool floating)
{
	struct airq_info *info = container_of(airq, struct airq_info, airq);
	unsigned long ai;

	inc_irq_stat(IRQIO_VAI);
	read_lock(&info->lock);
	/* Walk through indicators field, summary indicator active. */
	for (ai = 0;;) {
		ai = airq_iv_scan(info->aiv, ai, airq_iv_end(info->aiv));
		if (ai == -1UL)
			break;
		vring_interrupt(0, (void *)airq_iv_get_ptr(info->aiv, ai));
	}
	*(get_summary_indicator(info)) = 0;
	smp_wmb();
	/* Walk through indicators field, summary indicator not active. */
	for (ai = 0;;) {
		ai = airq_iv_scan(info->aiv, ai, airq_iv_end(info->aiv));
		if (ai == -1UL)
			break;
		vring_interrupt(0, (void *)airq_iv_get_ptr(info->aiv, ai));
	}
	read_unlock(&info->lock);
}

static struct airq_info *new_airq_info(int index)
{
	struct airq_info *info;
	int rc;

	info = kzalloc(sizeof(*info), GFP_KERNEL);
	if (!info)
		return NULL;
	rwlock_init(&info->lock);
	info->aiv = airq_iv_create(VIRTIO_IV_BITS, AIRQ_IV_ALLOC | AIRQ_IV_PTR
				   | AIRQ_IV_CACHELINE);
	if (!info->aiv) {
		kfree(info);
		return NULL;
	}
	info->airq.handler = virtio_airq_handler;
	info->summary_indicator_idx = index;
	info->airq.lsi_ptr = get_summary_indicator(info);
	info->airq.lsi_mask = 0xff;
	info->airq.isc = VIRTIO_AIRQ_ISC;
	rc = register_adapter_interrupt(&info->airq);
	if (rc) {
		airq_iv_release(info->aiv);
		kfree(info);
		return NULL;
	}
	return info;
}

static unsigned long get_airq_indicator(struct virtqueue *vqs[], int nvqs,
					u64 *first, void **airq_info)
{
	int i, j;
	struct airq_info *info;
	unsigned long indicator_addr = 0;
	unsigned long bit, flags;

	for (i = 0; i < MAX_AIRQ_AREAS && !indicator_addr; i++) {
		mutex_lock(&airq_areas_lock);
		if (!airq_areas[i])
			airq_areas[i] = new_airq_info(i);
		info = airq_areas[i];
		mutex_unlock(&airq_areas_lock);
		if (!info)
			return 0;
		write_lock_irqsave(&info->lock, flags);
		bit = airq_iv_alloc(info->aiv, nvqs);
		if (bit == -1UL) {
			/* Not enough vacancies. */
			write_unlock_irqrestore(&info->lock, flags);
			continue;
		}
		*first = bit;
		*airq_info = info;
		indicator_addr = (unsigned long)info->aiv->vector;
		for (j = 0; j < nvqs; j++) {
			airq_iv_set_ptr(info->aiv, bit + j,
					(unsigned long)vqs[j]);
		}
		write_unlock_irqrestore(&info->lock, flags);
	}
	return indicator_addr;
}

static void virtio_ccw_drop_indicators(struct virtio_ccw_device *vcdev)
{
	struct virtio_ccw_vq_info *info;

	if (!vcdev->airq_info)
		return;
	list_for_each_entry(info, &vcdev->virtqueues, node)
		drop_airq_indicator(info->vq, vcdev->airq_info);
}

static int doing_io(struct virtio_ccw_device *vcdev, __u32 flag)
{
	unsigned long flags;
	__u32 ret;

	spin_lock_irqsave(get_ccwdev_lock(vcdev->cdev), flags);
	if (vcdev->err)
		ret = 0;
	else
		ret = vcdev->curr_io & flag;
	spin_unlock_irqrestore(get_ccwdev_lock(vcdev->cdev), flags);
	return ret;
}

static int ccw_io_helper(struct virtio_ccw_device *vcdev,
			 struct ccw1 *ccw, __u32 intparm)
{
	int ret;
	unsigned long flags;
	int flag = intparm & VIRTIO_CCW_INTPARM_MASK;

	mutex_lock(&vcdev->io_lock);
	do {
		spin_lock_irqsave(get_ccwdev_lock(vcdev->cdev), flags);
		ret = ccw_device_start(vcdev->cdev, ccw, intparm, 0, 0);
		if (!ret) {
			if (!vcdev->curr_io)
				vcdev->err = 0;
			vcdev->curr_io |= flag;
		}
		spin_unlock_irqrestore(get_ccwdev_lock(vcdev->cdev), flags);
		cpu_relax();
	} while (ret == -EBUSY);
	wait_event(vcdev->wait_q, doing_io(vcdev, flag) == 0);
	ret = ret ? ret : vcdev->err;
	mutex_unlock(&vcdev->io_lock);
	return ret;
}

static void virtio_ccw_drop_indicator(struct virtio_ccw_device *vcdev,
				      struct ccw1 *ccw)
{
	int ret;
	unsigned long *indicatorp = NULL;
	struct virtio_thinint_area *thinint_area = NULL;
	struct airq_info *airq_info = vcdev->airq_info;

	if (vcdev->is_thinint) {
		thinint_area = ccw_device_dma_zalloc(vcdev->cdev,
						     sizeof(*thinint_area));
		if (!thinint_area)
			return;
		thinint_area->summary_indicator =
			(unsigned long) get_summary_indicator(airq_info);
		thinint_area->isc = VIRTIO_AIRQ_ISC;
		ccw->cmd_code = CCW_CMD_SET_IND_ADAPTER;
		ccw->count = sizeof(*thinint_area);
		ccw->cda = (__u32)(unsigned long) thinint_area;
	} else {
		/* payload is the address of the indicators */
		indicatorp = ccw_device_dma_zalloc(vcdev->cdev,
						   sizeof(indicators(vcdev)));
		if (!indicatorp)
			return;
		*indicatorp = 0;
		ccw->cmd_code = CCW_CMD_SET_IND;
		ccw->count = sizeof(indicators(vcdev));
		ccw->cda = (__u32)(unsigned long) indicatorp;
	}
	/* Deregister indicators from host. */
	*indicators(vcdev) = 0;
	ccw->flags = 0;
	ret = ccw_io_helper(vcdev, ccw,
			    vcdev->is_thinint ?
			    VIRTIO_CCW_DOING_SET_IND_ADAPTER :
			    VIRTIO_CCW_DOING_SET_IND);
	if (ret && (ret != -ENODEV))
		dev_info(&vcdev->cdev->dev,
			 "Failed to deregister indicators (%d)\n", ret);
	else if (vcdev->is_thinint)
		virtio_ccw_drop_indicators(vcdev);
	ccw_device_dma_free(vcdev->cdev, indicatorp, sizeof(indicators(vcdev)));
	ccw_device_dma_free(vcdev->cdev, thinint_area, sizeof(*thinint_area));
}

static bool virtio_ccw_kvm_notify(struct virtqueue *vq)
{
	struct virtio_ccw_vq_info *info = vq->priv;
	struct virtio_ccw_device *vcdev;
	struct subchannel_id schid;

	vcdev = to_vc_device(info->vq->vdev);
	ccw_device_get_schid(vcdev->cdev, &schid);
	BUILD_BUG_ON(sizeof(struct subchannel_id) != sizeof(unsigned int));
	info->cookie = kvm_hypercall3(KVM_S390_VIRTIO_CCW_NOTIFY,
				      *((unsigned int *)&schid),
				      vq->index, info->cookie);
	if (info->cookie < 0)
		return false;
	return true;
}

static int virtio_ccw_read_vq_conf(struct virtio_ccw_device *vcdev,
				   struct ccw1 *ccw, int index)
{
	int ret;

	vcdev->dma_area->config_block.index = index;
	ccw->cmd_code = CCW_CMD_READ_VQ_CONF;
	ccw->flags = 0;
	ccw->count = sizeof(struct vq_config_block);
	ccw->cda = (__u32)(unsigned long)(&vcdev->dma_area->config_block);
	ret = ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_READ_VQ_CONF);
	if (ret)
		return ret;
	return vcdev->dma_area->config_block.num ?: -ENOENT;
}

static void virtio_ccw_del_vq(struct virtqueue *vq, struct ccw1 *ccw)
{
	struct virtio_ccw_device *vcdev = to_vc_device(vq->vdev);
	struct virtio_ccw_vq_info *info = vq->priv;
	unsigned long flags;
	int ret;
	unsigned int index = vq->index;

	/* Remove from our list. */
	spin_lock_irqsave(&vcdev->lock, flags);
	list_del(&info->node);
	spin_unlock_irqrestore(&vcdev->lock, flags);

	/* Release from host. */
	if (vcdev->revision == 0) {
		info->info_block->l.queue = 0;
		info->info_block->l.align = 0;
		info->info_block->l.index = index;
		info->info_block->l.num = 0;
		ccw->count = sizeof(info->info_block->l);
	} else {
		info->info_block->s.desc = 0;
		info->info_block->s.index = index;
		info->info_block->s.num = 0;
		info->info_block->s.avail = 0;
		info->info_block->s.used = 0;
		ccw->count = sizeof(info->info_block->s);
	}
	ccw->cmd_code = CCW_CMD_SET_VQ;
	ccw->flags = 0;
	ccw->cda = (__u32)(unsigned long)(info->info_block);
	ret = ccw_io_helper(vcdev, ccw,
			    VIRTIO_CCW_DOING_SET_VQ | index);
	/*
	 * -ENODEV isn't considered an error: The device is gone anyway.
	 * This may happen on device detach.
	 */
	if (ret && (ret != -ENODEV))
		dev_warn(&vq->vdev->dev, "Error %d while deleting queue %d\n",
			 ret, index);

	vring_del_virtqueue(vq);
	ccw_device_dma_free(vcdev->cdev, info->info_block,
			    sizeof(*info->info_block));
	kfree(info);
}

static void virtio_ccw_del_vqs(struct virtio_device *vdev)
{
	struct virtqueue *vq, *n;
	struct ccw1 *ccw;
	struct virtio_ccw_device *vcdev = to_vc_device(vdev);

	ccw = ccw_device_dma_zalloc(vcdev->cdev, sizeof(*ccw));
	if (!ccw)
		return;

	virtio_ccw_drop_indicator(vcdev, ccw);

	list_for_each_entry_safe(vq, n, &vdev->vqs, list)
		virtio_ccw_del_vq(vq, ccw);

	ccw_device_dma_free(vcdev->cdev, ccw, sizeof(*ccw));
}

static struct virtqueue *virtio_ccw_setup_vq(struct virtio_device *vdev,
					     int i, vq_callback_t *callback,
					     const char *name, bool ctx,
					     struct ccw1 *ccw)
{
	struct virtio_ccw_device *vcdev = to_vc_device(vdev);
	int err;
	struct virtqueue *vq = NULL;
	struct virtio_ccw_vq_info *info;
	u64 queue;
	unsigned long flags;
	bool may_reduce;

	/* Allocate queue. */
	info = kzalloc(sizeof(struct virtio_ccw_vq_info), GFP_KERNEL);
	if (!info) {
		dev_warn(&vcdev->cdev->dev, "no info\n");
		err = -ENOMEM;
		goto out_err;
	}
	info->info_block = ccw_device_dma_zalloc(vcdev->cdev,
						 sizeof(*info->info_block));
	if (!info->info_block) {
		dev_warn(&vcdev->cdev->dev, "no info block\n");
		err = -ENOMEM;
		goto out_err;
	}
	info->num = virtio_ccw_read_vq_conf(vcdev, ccw, i);
	if (info->num < 0) {
		err = info->num;
		goto out_err;
	}
	may_reduce = vcdev->revision > 0;
	vq = vring_create_virtqueue(i, info->num, KVM_VIRTIO_CCW_RING_ALIGN,
				    vdev, true, may_reduce, ctx,
				    virtio_ccw_kvm_notify, callback, name);

	if (!vq) {
		/* For now, we fail if we can't get the requested size. */
		dev_warn(&vcdev->cdev->dev, "no vq\n");
		err = -ENOMEM;
		goto out_err;
	}
	/* it may have been reduced */
	info->num = virtqueue_get_vring_size(vq);

	/* Register it with the host. */
	queue = virtqueue_get_desc_addr(vq);
	if (vcdev->revision == 0) {
		info->info_block->l.queue = queue;
		info->info_block->l.align = KVM_VIRTIO_CCW_RING_ALIGN;
		info->info_block->l.index = i;
		info->info_block->l.num = info->num;
		ccw->count = sizeof(info->info_block->l);
	} else {
		info->info_block->s.desc = queue;
		info->info_block->s.index = i;
		info->info_block->s.num = info->num;
		info->info_block->s.avail = (__u64)virtqueue_get_avail_addr(vq);
		info->info_block->s.used = (__u64)virtqueue_get_used_addr(vq);
		ccw->count = sizeof(info->info_block->s);
	}
	ccw->cmd_code = CCW_CMD_SET_VQ;
	ccw->flags = 0;
	ccw->cda = (__u32)(unsigned long)(info->info_block);
	err = ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_SET_VQ | i);
	if (err) {
		dev_warn(&vcdev->cdev->dev, "SET_VQ failed\n");
		goto out_err;
	}

	info->vq = vq;
	vq->priv = info;

	/* Save it to our list. */
	spin_lock_irqsave(&vcdev->lock, flags);
	list_add(&info->node, &vcdev->virtqueues);
	spin_unlock_irqrestore(&vcdev->lock, flags);

	return vq;

out_err:
	if (vq)
		vring_del_virtqueue(vq);
	if (info) {
		ccw_device_dma_free(vcdev->cdev, info->info_block,
				    sizeof(*info->info_block));
	}
	kfree(info);
	return ERR_PTR(err);
}

static int virtio_ccw_register_adapter_ind(struct virtio_ccw_device *vcdev,
					   struct virtqueue *vqs[], int nvqs,
					   struct ccw1 *ccw)
{
	int ret;
	struct virtio_thinint_area *thinint_area = NULL;
	struct airq_info *info;

	thinint_area = ccw_device_dma_zalloc(vcdev->cdev,
					     sizeof(*thinint_area));
	if (!thinint_area) {
		ret = -ENOMEM;
		goto out;
	}
	/* Try to get an indicator. */
	thinint_area->indicator = get_airq_indicator(vqs, nvqs,
						     &thinint_area->bit_nr,
						     &vcdev->airq_info);
	if (!thinint_area->indicator) {
		ret = -ENOSPC;
		goto out;
	}
	info = vcdev->airq_info;
	thinint_area->summary_indicator =
		(unsigned long) get_summary_indicator(info);
	thinint_area->isc = VIRTIO_AIRQ_ISC;
	ccw->cmd_code = CCW_CMD_SET_IND_ADAPTER;
	ccw->flags = CCW_FLAG_SLI;
	ccw->count = sizeof(*thinint_area);
	ccw->cda = (__u32)(unsigned long)thinint_area;
	ret = ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_SET_IND_ADAPTER);
	if (ret) {
		if (ret == -EOPNOTSUPP) {
			/*
			 * The host does not support adapter interrupts
			 * for virtio-ccw, stop trying.
			 */
			virtio_ccw_use_airq = 0;
			pr_info("Adapter interrupts unsupported on host\n");
		} else
			dev_warn(&vcdev->cdev->dev,
				 "enabling adapter interrupts = %d\n", ret);
		virtio_ccw_drop_indicators(vcdev);
	}
out:
	ccw_device_dma_free(vcdev->cdev, thinint_area, sizeof(*thinint_area));
	return ret;
}

static int virtio_ccw_find_vqs(struct virtio_device *vdev, unsigned nvqs,
			       struct virtqueue *vqs[],
			       vq_callback_t *callbacks[],
			       const char * const names[],
			       const bool *ctx,
			       struct irq_affinity *desc)
{
	struct virtio_ccw_device *vcdev = to_vc_device(vdev);
	unsigned long *indicatorp = NULL;
	int ret, i, queue_idx = 0;
	struct ccw1 *ccw;

	ccw = ccw_device_dma_zalloc(vcdev->cdev, sizeof(*ccw));
	if (!ccw)
		return -ENOMEM;

	for (i = 0; i < nvqs; ++i) {
		if (!names[i]) {
			vqs[i] = NULL;
			continue;
		}

		vqs[i] = virtio_ccw_setup_vq(vdev, queue_idx++, callbacks[i],
					     names[i], ctx ? ctx[i] : false,
					     ccw);
		if (IS_ERR(vqs[i])) {
			ret = PTR_ERR(vqs[i]);
			vqs[i] = NULL;
			goto out;
		}
	}
	ret = -ENOMEM;
	/*
	 * We need a data area under 2G to communicate. Our payload is
	 * the address of the indicators.
	*/
	indicatorp = ccw_device_dma_zalloc(vcdev->cdev,
					   sizeof(indicators(vcdev)));
	if (!indicatorp)
		goto out;
	*indicatorp = (unsigned long) indicators(vcdev);
	if (vcdev->is_thinint) {
		ret = virtio_ccw_register_adapter_ind(vcdev, vqs, nvqs, ccw);
		if (ret)
			/* no error, just fall back to legacy interrupts */
			vcdev->is_thinint = false;
	}
	if (!vcdev->is_thinint) {
		/* Register queue indicators with host. */
		*indicators(vcdev) = 0;
		ccw->cmd_code = CCW_CMD_SET_IND;
		ccw->flags = 0;
		ccw->count = sizeof(indicators(vcdev));
		ccw->cda = (__u32)(unsigned long) indicatorp;
		ret = ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_SET_IND);
		if (ret)
			goto out;
	}
	/* Register indicators2 with host for config changes */
	*indicatorp = (unsigned long) indicators2(vcdev);
	*indicators2(vcdev) = 0;
	ccw->cmd_code = CCW_CMD_SET_CONF_IND;
	ccw->flags = 0;
	ccw->count = sizeof(indicators2(vcdev));
	ccw->cda = (__u32)(unsigned long) indicatorp;
	ret = ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_SET_CONF_IND);
	if (ret)
		goto out;

	if (indicatorp)
		ccw_device_dma_free(vcdev->cdev, indicatorp,
				    sizeof(indicators(vcdev)));
	ccw_device_dma_free(vcdev->cdev, ccw, sizeof(*ccw));
	return 0;
out:
	if (indicatorp)
		ccw_device_dma_free(vcdev->cdev, indicatorp,
				    sizeof(indicators(vcdev)));
	ccw_device_dma_free(vcdev->cdev, ccw, sizeof(*ccw));
	virtio_ccw_del_vqs(vdev);
	return ret;
}

static void virtio_ccw_reset(struct virtio_device *vdev)
{
	struct virtio_ccw_device *vcdev = to_vc_device(vdev);
	struct ccw1 *ccw;

	ccw = ccw_device_dma_zalloc(vcdev->cdev, sizeof(*ccw));
	if (!ccw)
		return;

	/* Zero status bits. */
	vcdev->dma_area->status = 0;

	/* Send a reset ccw on device. */
	ccw->cmd_code = CCW_CMD_VDEV_RESET;
	ccw->flags = 0;
	ccw->count = 0;
	ccw->cda = 0;
	ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_RESET);
	ccw_device_dma_free(vcdev->cdev, ccw, sizeof(*ccw));
}

static u64 virtio_ccw_get_features(struct virtio_device *vdev)
{
	struct virtio_ccw_device *vcdev = to_vc_device(vdev);
	struct virtio_feature_desc *features;
	int ret;
	u64 rc;
	struct ccw1 *ccw;

	ccw = ccw_device_dma_zalloc(vcdev->cdev, sizeof(*ccw));
	if (!ccw)
		return 0;

	features = ccw_device_dma_zalloc(vcdev->cdev, sizeof(*features));
	if (!features) {
		rc = 0;
		goto out_free;
	}
	/* Read the feature bits from the host. */
	features->index = 0;
	ccw->cmd_code = CCW_CMD_READ_FEAT;
	ccw->flags = 0;
	ccw->count = sizeof(*features);
	ccw->cda = (__u32)(unsigned long)features;
	ret = ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_READ_FEAT);
	if (ret) {
		rc = 0;
		goto out_free;
	}

	rc = le32_to_cpu(features->features);

	if (vcdev->revision == 0)
		goto out_free;

	/* Read second half of the feature bits from the host. */
	features->index = 1;
	ccw->cmd_code = CCW_CMD_READ_FEAT;
	ccw->flags = 0;
	ccw->count = sizeof(*features);
	ccw->cda = (__u32)(unsigned long)features;
	ret = ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_READ_FEAT);
	if (ret == 0)
		rc |= (u64)le32_to_cpu(features->features) << 32;

out_free:
	ccw_device_dma_free(vcdev->cdev, features, sizeof(*features));
	ccw_device_dma_free(vcdev->cdev, ccw, sizeof(*ccw));
	return rc;
}

static void ccw_transport_features(struct virtio_device *vdev)
{
	/*
	 * Currently nothing to do here.
	 */
}

static int virtio_ccw_finalize_features(struct virtio_device *vdev)
{
	struct virtio_ccw_device *vcdev = to_vc_device(vdev);
	struct virtio_feature_desc *features;
	struct ccw1 *ccw;
	int ret;

	if (vcdev->revision >= 1 &&
	    !__virtio_test_bit(vdev, VIRTIO_F_VERSION_1)) {
		dev_err(&vdev->dev, "virtio: device uses revision 1 "
			"but does not have VIRTIO_F_VERSION_1\n");
		return -EINVAL;
	}

	ccw = ccw_device_dma_zalloc(vcdev->cdev, sizeof(*ccw));
	if (!ccw)
		return -ENOMEM;

	features = ccw_device_dma_zalloc(vcdev->cdev, sizeof(*features));
	if (!features) {
		ret = -ENOMEM;
		goto out_free;
	}
	/* Give virtio_ring a chance to accept features. */
	vring_transport_features(vdev);

	/* Give virtio_ccw a chance to accept features. */
	ccw_transport_features(vdev);

	features->index = 0;
	features->features = cpu_to_le32((u32)vdev->features);
	/* Write the first half of the feature bits to the host. */
	ccw->cmd_code = CCW_CMD_WRITE_FEAT;
	ccw->flags = 0;
	ccw->count = sizeof(*features);
	ccw->cda = (__u32)(unsigned long)features;
	ret = ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_WRITE_FEAT);
	if (ret)
		goto out_free;

	if (vcdev->revision == 0)
		goto out_free;

	features->index = 1;
	features->features = cpu_to_le32(vdev->features >> 32);
	/* Write the second half of the feature bits to the host. */
	ccw->cmd_code = CCW_CMD_WRITE_FEAT;
	ccw->flags = 0;
	ccw->count = sizeof(*features);
	ccw->cda = (__u32)(unsigned long)features;
	ret = ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_WRITE_FEAT);

out_free:
	ccw_device_dma_free(vcdev->cdev, features, sizeof(*features));
	ccw_device_dma_free(vcdev->cdev, ccw, sizeof(*ccw));

	return ret;
}

static void virtio_ccw_get_config(struct virtio_device *vdev,
				  unsigned int offset, void *buf, unsigned len)
{
	struct virtio_ccw_device *vcdev = to_vc_device(vdev);
	int ret;
	struct ccw1 *ccw;
	void *config_area;
	unsigned long flags;

	ccw = ccw_device_dma_zalloc(vcdev->cdev, sizeof(*ccw));
	if (!ccw)
		return;

	config_area = ccw_device_dma_zalloc(vcdev->cdev,
					    VIRTIO_CCW_CONFIG_SIZE);
	if (!config_area)
		goto out_free;

	/* Read the config area from the host. */
	ccw->cmd_code = CCW_CMD_READ_CONF;
	ccw->flags = 0;
	ccw->count = offset + len;
	ccw->cda = (__u32)(unsigned long)config_area;
	ret = ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_READ_CONFIG);
	if (ret)
		goto out_free;

	spin_lock_irqsave(&vcdev->lock, flags);
	memcpy(vcdev->config, config_area, offset + len);
	if (vcdev->config_ready < offset + len)
		vcdev->config_ready = offset + len;
	spin_unlock_irqrestore(&vcdev->lock, flags);
	if (buf)
		memcpy(buf, config_area + offset, len);

out_free:
	ccw_device_dma_free(vcdev->cdev, config_area, VIRTIO_CCW_CONFIG_SIZE);
	ccw_device_dma_free(vcdev->cdev, ccw, sizeof(*ccw));
}

static void virtio_ccw_set_config(struct virtio_device *vdev,
				  unsigned int offset, const void *buf,
				  unsigned len)
{
	struct virtio_ccw_device *vcdev = to_vc_device(vdev);
	struct ccw1 *ccw;
	void *config_area;
	unsigned long flags;

	ccw = ccw_device_dma_zalloc(vcdev->cdev, sizeof(*ccw));
	if (!ccw)
		return;

	config_area = ccw_device_dma_zalloc(vcdev->cdev,
					    VIRTIO_CCW_CONFIG_SIZE);
	if (!config_area)
		goto out_free;

	/* Make sure we don't overwrite fields. */
	if (vcdev->config_ready < offset)
		virtio_ccw_get_config(vdev, 0, NULL, offset);
	spin_lock_irqsave(&vcdev->lock, flags);
	memcpy(&vcdev->config[offset], buf, len);
	/* Write the config area to the host. */
	memcpy(config_area, vcdev->config, sizeof(vcdev->config));
	spin_unlock_irqrestore(&vcdev->lock, flags);
	ccw->cmd_code = CCW_CMD_WRITE_CONF;
	ccw->flags = 0;
	ccw->count = offset + len;
	ccw->cda = (__u32)(unsigned long)config_area;
	ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_WRITE_CONFIG);

out_free:
	ccw_device_dma_free(vcdev->cdev, config_area, VIRTIO_CCW_CONFIG_SIZE);
	ccw_device_dma_free(vcdev->cdev, ccw, sizeof(*ccw));
}

static u8 virtio_ccw_get_status(struct virtio_device *vdev)
{
	struct virtio_ccw_device *vcdev = to_vc_device(vdev);
	u8 old_status = vcdev->dma_area->status;
	struct ccw1 *ccw;

	if (vcdev->revision < 2)
		return vcdev->dma_area->status;

	ccw = ccw_device_dma_zalloc(vcdev->cdev, sizeof(*ccw));
	if (!ccw)
		return old_status;

	ccw->cmd_code = CCW_CMD_READ_STATUS;
	ccw->flags = 0;
	ccw->count = sizeof(vcdev->dma_area->status);
	ccw->cda = (__u32)(unsigned long)&vcdev->dma_area->status;
	ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_READ_STATUS);
/*
 * If the channel program failed (should only happen if the device
 * was hotunplugged, and then we clean up via the machine check
 * handler anyway), vcdev->dma_area->status was not overwritten and we just
 * return the old status, which is fine.
*/
	ccw_device_dma_free(vcdev->cdev, ccw, sizeof(*ccw));

	return vcdev->dma_area->status;
}

static void virtio_ccw_set_status(struct virtio_device *vdev, u8 status)
{
	struct virtio_ccw_device *vcdev = to_vc_device(vdev);
	u8 old_status = vcdev->dma_area->status;
	struct ccw1 *ccw;
	int ret;

	ccw = ccw_device_dma_zalloc(vcdev->cdev, sizeof(*ccw));
	if (!ccw)
		return;

	/* Write the status to the host. */
	vcdev->dma_area->status = status;
	ccw->cmd_code = CCW_CMD_WRITE_STATUS;
	ccw->flags = 0;
	ccw->count = sizeof(status);
	ccw->cda = (__u32)(unsigned long)&vcdev->dma_area->status;
	/* We use ssch for setting the status which is a serializing
	 * instruction that guarantees the memory writes have
	 * completed before ssch.
	 */
	ret = ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_WRITE_STATUS);
	/* Write failed? We assume status is unchanged. */
	if (ret)
		vcdev->dma_area->status = old_status;
	ccw_device_dma_free(vcdev->cdev, ccw, sizeof(*ccw));
}

static const char *virtio_ccw_bus_name(struct virtio_device *vdev)
{
	struct virtio_ccw_device *vcdev = to_vc_device(vdev);

	return dev_name(&vcdev->cdev->dev);
}

static void virtio_ccw_synchronize_cbs(struct virtio_device *vdev)
{
	struct virtio_ccw_device *vcdev = to_vc_device(vdev);
	struct airq_info *info = vcdev->airq_info;

	if (info) {
		/*
		 * This device uses adapter interrupts: synchronize with
		 * vring_interrupt() called by virtio_airq_handler()
		 * via the indicator area lock.
		 */
		write_lock_irq(&info->lock);
		write_unlock_irq(&info->lock);
	} else {
		/* This device uses classic interrupts: synchronize
		 * with vring_interrupt() called by
		 * virtio_ccw_int_handler() via the per-device
		 * irq_lock
		 */
		write_lock_irq(&vcdev->irq_lock);
		write_unlock_irq(&vcdev->irq_lock);
	}
}

static const struct virtio_config_ops virtio_ccw_config_ops = {
	.get_features = virtio_ccw_get_features,
	.finalize_features = virtio_ccw_finalize_features,
	.get = virtio_ccw_get_config,
	.set = virtio_ccw_set_config,
	.get_status = virtio_ccw_get_status,
	.set_status = virtio_ccw_set_status,
	.reset = virtio_ccw_reset,
	.find_vqs = virtio_ccw_find_vqs,
	.del_vqs = virtio_ccw_del_vqs,
	.bus_name = virtio_ccw_bus_name,
	.synchronize_cbs = virtio_ccw_synchronize_cbs,
};


/*
 * ccw bus driver related functions
 */

static void virtio_ccw_release_dev(struct device *_d)
{
	struct virtio_device *dev = dev_to_virtio(_d);
	struct virtio_ccw_device *vcdev = to_vc_device(dev);

	ccw_device_dma_free(vcdev->cdev, vcdev->dma_area,
			    sizeof(*vcdev->dma_area));
	kfree(vcdev);
}

static int irb_is_error(struct irb *irb)
{
	if (scsw_cstat(&irb->scsw) != 0)
		return 1;
	if (scsw_dstat(&irb->scsw) & ~(DEV_STAT_CHN_END | DEV_STAT_DEV_END))
		return 1;
	if (scsw_cc(&irb->scsw) != 0)
		return 1;
	return 0;
}

static struct virtqueue *virtio_ccw_vq_by_ind(struct virtio_ccw_device *vcdev,
					      int index)
{
	struct virtio_ccw_vq_info *info;
	unsigned long flags;
	struct virtqueue *vq;

	vq = NULL;
	spin_lock_irqsave(&vcdev->lock, flags);
	list_for_each_entry(info, &vcdev->virtqueues, node) {
		if (info->vq->index == index) {
			vq = info->vq;
			break;
		}
	}
	spin_unlock_irqrestore(&vcdev->lock, flags);
	return vq;
}

static void virtio_ccw_check_activity(struct virtio_ccw_device *vcdev,
				      __u32 activity)
{
	if (vcdev->curr_io & activity) {
		switch (activity) {
		case VIRTIO_CCW_DOING_READ_FEAT:
		case VIRTIO_CCW_DOING_WRITE_FEAT:
		case VIRTIO_CCW_DOING_READ_CONFIG:
		case VIRTIO_CCW_DOING_WRITE_CONFIG:
		case VIRTIO_CCW_DOING_WRITE_STATUS:
		case VIRTIO_CCW_DOING_READ_STATUS:
		case VIRTIO_CCW_DOING_SET_VQ:
		case VIRTIO_CCW_DOING_SET_IND:
		case VIRTIO_CCW_DOING_SET_CONF_IND:
		case VIRTIO_CCW_DOING_RESET:
		case VIRTIO_CCW_DOING_READ_VQ_CONF:
		case VIRTIO_CCW_DOING_SET_IND_ADAPTER:
		case VIRTIO_CCW_DOING_SET_VIRTIO_REV:
			vcdev->curr_io &= ~activity;
			wake_up(&vcdev->wait_q);
			break;
		default:
			/* don't know what to do... */
			dev_warn(&vcdev->cdev->dev,
				 "Suspicious activity '%08x'\n", activity);
			WARN_ON(1);
			break;
		}
	}
}

static void virtio_ccw_int_handler(struct ccw_device *cdev,
				   unsigned long intparm,
				   struct irb *irb)
{
	__u32 activity = intparm & VIRTIO_CCW_INTPARM_MASK;
	struct virtio_ccw_device *vcdev = dev_get_drvdata(&cdev->dev);
	int i;
	struct virtqueue *vq;

	if (!vcdev)
		return;
	if (IS_ERR(irb)) {
		vcdev->err = PTR_ERR(irb);
		virtio_ccw_check_activity(vcdev, activity);
		/* Don't poke around indicators, something's wrong. */
		return;
	}
	/* Check if it's a notification from the host. */
	if ((intparm == 0) &&
	    (scsw_stctl(&irb->scsw) ==
	     (SCSW_STCTL_ALERT_STATUS | SCSW_STCTL_STATUS_PEND))) {
		/* OK */
	}
	if (irb_is_error(irb)) {
		/* Command reject? */
		if ((scsw_dstat(&irb->scsw) & DEV_STAT_UNIT_CHECK) &&
		    (irb->ecw[0] & SNS0_CMD_REJECT))
			vcdev->err = -EOPNOTSUPP;
		else
			/* Map everything else to -EIO. */
			vcdev->err = -EIO;
	}
	virtio_ccw_check_activity(vcdev, activity);
	/* Interrupts are disabled here */
	read_lock(&vcdev->irq_lock);
	for_each_set_bit(i, indicators(vcdev),
			 sizeof(*indicators(vcdev)) * BITS_PER_BYTE) {
		/* The bit clear must happen before the vring kick. */
		clear_bit(i, indicators(vcdev));
		barrier();
		vq = virtio_ccw_vq_by_ind(vcdev, i);
		vring_interrupt(0, vq);
	}
	read_unlock(&vcdev->irq_lock);
	if (test_bit(0, indicators2(vcdev))) {
		virtio_config_changed(&vcdev->vdev);
		clear_bit(0, indicators2(vcdev));
	}
}

/*
 * We usually want to autoonline all devices, but give the admin
 * a way to exempt devices from this.
 */
#define __DEV_WORDS ((__MAX_SUBCHANNEL + (8*sizeof(long) - 1)) / \
		     (8*sizeof(long)))
static unsigned long devs_no_auto[__MAX_SSID + 1][__DEV_WORDS];

static char *no_auto = "";

module_param(no_auto, charp, 0444);
MODULE_PARM_DESC(no_auto, "list of ccw bus id ranges not to be auto-onlined");

static int virtio_ccw_check_autoonline(struct ccw_device *cdev)
{
	struct ccw_dev_id id;

	ccw_device_get_id(cdev, &id);
	if (test_bit(id.devno, devs_no_auto[id.ssid]))
		return 0;
	return 1;
}

static void virtio_ccw_auto_online(void *data, async_cookie_t cookie)
{
	struct ccw_device *cdev = data;
	int ret;

	ret = ccw_device_set_online(cdev);
	if (ret)
		dev_warn(&cdev->dev, "Failed to set online: %d\n", ret);
}

static int virtio_ccw_probe(struct ccw_device *cdev)
{
	cdev->handler = virtio_ccw_int_handler;

	if (virtio_ccw_check_autoonline(cdev))
		async_schedule(virtio_ccw_auto_online, cdev);
	return 0;
}

static struct virtio_ccw_device *virtio_grab_drvdata(struct ccw_device *cdev)
{
	unsigned long flags;
	struct virtio_ccw_device *vcdev;

	spin_lock_irqsave(get_ccwdev_lock(cdev), flags);
	vcdev = dev_get_drvdata(&cdev->dev);
	if (!vcdev || vcdev->going_away) {
		spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);
		return NULL;
	}
	vcdev->going_away = true;
	spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);
	return vcdev;
}

static void virtio_ccw_remove(struct ccw_device *cdev)
{
	unsigned long flags;
	struct virtio_ccw_device *vcdev = virtio_grab_drvdata(cdev);

	if (vcdev && cdev->online) {
		if (vcdev->device_lost)
			virtio_break_device(&vcdev->vdev);
		unregister_virtio_device(&vcdev->vdev);
		spin_lock_irqsave(get_ccwdev_lock(cdev), flags);
		dev_set_drvdata(&cdev->dev, NULL);
		spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);
	}
	cdev->handler = NULL;
}

static int virtio_ccw_offline(struct ccw_device *cdev)
{
	unsigned long flags;
	struct virtio_ccw_device *vcdev = virtio_grab_drvdata(cdev);

	if (!vcdev)
		return 0;
	if (vcdev->device_lost)
		virtio_break_device(&vcdev->vdev);
	unregister_virtio_device(&vcdev->vdev);
	spin_lock_irqsave(get_ccwdev_lock(cdev), flags);
	dev_set_drvdata(&cdev->dev, NULL);
	spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);
	return 0;
}

static int virtio_ccw_set_transport_rev(struct virtio_ccw_device *vcdev)
{
	struct virtio_rev_info *rev;
	struct ccw1 *ccw;
	int ret;

	ccw = ccw_device_dma_zalloc(vcdev->cdev, sizeof(*ccw));
	if (!ccw)
		return -ENOMEM;
	rev = ccw_device_dma_zalloc(vcdev->cdev, sizeof(*rev));
	if (!rev) {
		ccw_device_dma_free(vcdev->cdev, ccw, sizeof(*ccw));
		return -ENOMEM;
	}

	/* Set transport revision */
	ccw->cmd_code = CCW_CMD_SET_VIRTIO_REV;
	ccw->flags = 0;
	ccw->count = sizeof(*rev);
	ccw->cda = (__u32)(unsigned long)rev;

	vcdev->revision = VIRTIO_CCW_REV_MAX;
	do {
		rev->revision = vcdev->revision;
		/* none of our supported revisions carry payload */
		rev->length = 0;
		ret = ccw_io_helper(vcdev, ccw,
				    VIRTIO_CCW_DOING_SET_VIRTIO_REV);
		if (ret == -EOPNOTSUPP) {
			if (vcdev->revision == 0)
				/*
				 * The host device does not support setting
				 * the revision: let's operate it in legacy
				 * mode.
				 */
				ret = 0;
			else
				vcdev->revision--;
		}
	} while (ret == -EOPNOTSUPP);

	ccw_device_dma_free(vcdev->cdev, ccw, sizeof(*ccw));
	ccw_device_dma_free(vcdev->cdev, rev, sizeof(*rev));
	return ret;
}

static int virtio_ccw_online(struct ccw_device *cdev)
{
	int ret;
	struct virtio_ccw_device *vcdev;
	unsigned long flags;

	vcdev = kzalloc(sizeof(*vcdev), GFP_KERNEL);
	if (!vcdev) {
		dev_warn(&cdev->dev, "Could not get memory for virtio\n");
		ret = -ENOMEM;
		goto out_free;
	}
	vcdev->vdev.dev.parent = &cdev->dev;
	vcdev->cdev = cdev;
	vcdev->dma_area = ccw_device_dma_zalloc(vcdev->cdev,
						sizeof(*vcdev->dma_area));
	if (!vcdev->dma_area) {
		ret = -ENOMEM;
		goto out_free;
	}

	vcdev->is_thinint = virtio_ccw_use_airq; /* at least try */

	vcdev->vdev.dev.release = virtio_ccw_release_dev;
	vcdev->vdev.config = &virtio_ccw_config_ops;
	init_waitqueue_head(&vcdev->wait_q);
	INIT_LIST_HEAD(&vcdev->virtqueues);
	spin_lock_init(&vcdev->lock);
	rwlock_init(&vcdev->irq_lock);
	mutex_init(&vcdev->io_lock);

	spin_lock_irqsave(get_ccwdev_lock(cdev), flags);
	dev_set_drvdata(&cdev->dev, vcdev);
	spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);
	vcdev->vdev.id.vendor = cdev->id.cu_type;
	vcdev->vdev.id.device = cdev->id.cu_model;

	ret = virtio_ccw_set_transport_rev(vcdev);
	if (ret)
		goto out_free;

	ret = register_virtio_device(&vcdev->vdev);
	if (ret) {
		dev_warn(&cdev->dev, "Failed to register virtio device: %d\n",
			 ret);
		goto out_put;
	}
	return 0;
out_put:
	spin_lock_irqsave(get_ccwdev_lock(cdev), flags);
	dev_set_drvdata(&cdev->dev, NULL);
	spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);
	put_device(&vcdev->vdev.dev);
	return ret;
out_free:
	if (vcdev) {
		ccw_device_dma_free(vcdev->cdev, vcdev->dma_area,
				    sizeof(*vcdev->dma_area));
	}
	kfree(vcdev);
	return ret;
}

static int virtio_ccw_cio_notify(struct ccw_device *cdev, int event)
{
	int rc;
	struct virtio_ccw_device *vcdev = dev_get_drvdata(&cdev->dev);

	/*
	 * Make sure vcdev is set
	 * i.e. set_offline/remove callback not already running
	 */
	if (!vcdev)
		return NOTIFY_DONE;

	switch (event) {
	case CIO_GONE:
		vcdev->device_lost = true;
		rc = NOTIFY_DONE;
		break;
	case CIO_OPER:
		rc = NOTIFY_OK;
		break;
	default:
		rc = NOTIFY_DONE;
		break;
	}
	return rc;
}

static struct ccw_device_id virtio_ids[] = {
	{ CCW_DEVICE(0x3832, 0) },
	{},
};

static struct ccw_driver virtio_ccw_driver = {
	.driver = {
		.owner = THIS_MODULE,
		.name = "virtio_ccw",
	},
	.ids = virtio_ids,
	.probe = virtio_ccw_probe,
	.remove = virtio_ccw_remove,
	.set_offline = virtio_ccw_offline,
	.set_online = virtio_ccw_online,
	.notify = virtio_ccw_cio_notify,
	.int_class = IRQIO_VIR,
};

static int __init pure_hex(char **cp, unsigned int *val, int min_digit,
			   int max_digit, int max_val)
{
	int diff;

	diff = 0;
	*val = 0;

	while (diff <= max_digit) {
		int value = hex_to_bin(**cp);

		if (value < 0)
			break;
		*val = *val * 16 + value;
		(*cp)++;
		diff++;
	}

	if ((diff < min_digit) || (diff > max_digit) || (*val > max_val))
		return 1;

	return 0;
}

static int __init parse_busid(char *str, unsigned int *cssid,
			      unsigned int *ssid, unsigned int *devno)
{
	char *str_work;
	int rc, ret;

	rc = 1;

	if (*str == '\0')
		goto out;

	str_work = str;
	ret = pure_hex(&str_work, cssid, 1, 2, __MAX_CSSID);
	if (ret || (str_work[0] != '.'))
		goto out;
	str_work++;
	ret = pure_hex(&str_work, ssid, 1, 1, __MAX_SSID);
	if (ret || (str_work[0] != '.'))
		goto out;
	str_work++;
	ret = pure_hex(&str_work, devno, 4, 4, __MAX_SUBCHANNEL);
	if (ret || (str_work[0] != '\0'))
		goto out;

	rc = 0;
out:
	return rc;
}

static void __init no_auto_parse(void)
{
	unsigned int from_cssid, to_cssid, from_ssid, to_ssid, from, to;
	char *parm, *str;
	int rc;

	str = no_auto;
	while ((parm = strsep(&str, ","))) {
		rc = parse_busid(strsep(&parm, "-"), &from_cssid,
				 &from_ssid, &from);
		if (rc)
			continue;
		if (parm != NULL) {
			rc = parse_busid(parm, &to_cssid,
					 &to_ssid, &to);
			if ((from_ssid > to_ssid) ||
			    ((from_ssid == to_ssid) && (from > to)))
				rc = -EINVAL;
		} else {
			to_cssid = from_cssid;
			to_ssid = from_ssid;
			to = from;
		}
		if (rc)
			continue;
		while ((from_ssid < to_ssid) ||
		       ((from_ssid == to_ssid) && (from <= to))) {
			set_bit(from, devs_no_auto[from_ssid]);
			from++;
			if (from > __MAX_SUBCHANNEL) {
				from_ssid++;
				from = 0;
			}
		}
	}
}

static int __init virtio_ccw_init(void)
{
	int rc;

	/* parse no_auto string before we do anything further */
	no_auto_parse();

	summary_indicators = cio_dma_zalloc(MAX_AIRQ_AREAS);
	if (!summary_indicators)
		return -ENOMEM;
	rc = ccw_driver_register(&virtio_ccw_driver);
	if (rc)
		cio_dma_free(summary_indicators, MAX_AIRQ_AREAS);
	return rc;
}
device_initcall(virtio_ccw_init);