summaryrefslogtreecommitdiffstats
path: root/drivers/vfio/pci/vfio_pci.c
blob: 010e0f8b8e4fe0099dff900742ce4564391742a2 (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
/*
 * Copyright (C) 2012 Red Hat, Inc.  All rights reserved.
 *     Author: Alex Williamson <alex.williamson@redhat.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Derived from original vfio:
 * Copyright 2010 Cisco Systems, Inc.  All rights reserved.
 * Author: Tom Lyon, pugs@cisco.com
 */

#include <linux/device.h>
#include <linux/eventfd.h>
#include <linux/file.h>
#include <linux/interrupt.h>
#include <linux/iommu.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/notifier.h>
#include <linux/pci.h>
#include <linux/pm_runtime.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/uaccess.h>
#include <linux/vfio.h>

#include "vfio_pci_private.h"

#define DRIVER_VERSION  "0.2"
#define DRIVER_AUTHOR   "Alex Williamson <alex.williamson@redhat.com>"
#define DRIVER_DESC     "VFIO PCI - User Level meta-driver"

static bool nointxmask;
module_param_named(nointxmask, nointxmask, bool, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(nointxmask,
		  "Disable support for PCI 2.3 style INTx masking.  If this resolves problems for specific devices, report lspci -vvvxxx to linux-pci@vger.kernel.org so the device can be fixed automatically via the broken_intx_masking flag.");

static int vfio_pci_enable(struct vfio_pci_device *vdev)
{
	struct pci_dev *pdev = vdev->pdev;
	int ret;
	u16 cmd;
	u8 msix_pos;

	ret = pci_enable_device(pdev);
	if (ret)
		return ret;

	vdev->reset_works = (pci_reset_function(pdev) == 0);
	pci_save_state(pdev);
	vdev->pci_saved_state = pci_store_saved_state(pdev);
	if (!vdev->pci_saved_state)
		pr_debug("%s: Couldn't store %s saved state\n",
			 __func__, dev_name(&pdev->dev));

	ret = vfio_config_init(vdev);
	if (ret) {
		kfree(vdev->pci_saved_state);
		vdev->pci_saved_state = NULL;
		pci_disable_device(pdev);
		return ret;
	}

	if (likely(!nointxmask))
		vdev->pci_2_3 = pci_intx_mask_supported(pdev);

	pci_read_config_word(pdev, PCI_COMMAND, &cmd);
	if (vdev->pci_2_3 && (cmd & PCI_COMMAND_INTX_DISABLE)) {
		cmd &= ~PCI_COMMAND_INTX_DISABLE;
		pci_write_config_word(pdev, PCI_COMMAND, cmd);
	}

	msix_pos = pdev->msix_cap;
	if (msix_pos) {
		u16 flags;
		u32 table;

		pci_read_config_word(pdev, msix_pos + PCI_MSIX_FLAGS, &flags);
		pci_read_config_dword(pdev, msix_pos + PCI_MSIX_TABLE, &table);

		vdev->msix_bar = table & PCI_MSIX_TABLE_BIR;
		vdev->msix_offset = table & PCI_MSIX_TABLE_OFFSET;
		vdev->msix_size = ((flags & PCI_MSIX_FLAGS_QSIZE) + 1) * 16;
	} else
		vdev->msix_bar = 0xFF;

#ifdef CONFIG_VFIO_PCI_VGA
	if ((pdev->class >> 8) == PCI_CLASS_DISPLAY_VGA)
		vdev->has_vga = true;
#endif

	return 0;
}

static void vfio_pci_disable(struct vfio_pci_device *vdev)
{
	struct pci_dev *pdev = vdev->pdev;
	int bar;

	pci_disable_device(pdev);

	vfio_pci_set_irqs_ioctl(vdev, VFIO_IRQ_SET_DATA_NONE |
				VFIO_IRQ_SET_ACTION_TRIGGER,
				vdev->irq_type, 0, 0, NULL);

	vdev->virq_disabled = false;

	vfio_config_free(vdev);

	for (bar = PCI_STD_RESOURCES; bar <= PCI_STD_RESOURCE_END; bar++) {
		if (!vdev->barmap[bar])
			continue;
		pci_iounmap(pdev, vdev->barmap[bar]);
		pci_release_selected_regions(pdev, 1 << bar);
		vdev->barmap[bar] = NULL;
	}

	/*
	 * If we have saved state, restore it.  If we can reset the device,
	 * even better.  Resetting with current state seems better than
	 * nothing, but saving and restoring current state without reset
	 * is just busy work.
	 */
	if (pci_load_and_free_saved_state(pdev, &vdev->pci_saved_state)) {
		pr_info("%s: Couldn't reload %s saved state\n",
			__func__, dev_name(&pdev->dev));

		if (!vdev->reset_works)
			return;

		pci_save_state(pdev);
	}

	/*
	 * Disable INTx and MSI, presumably to avoid spurious interrupts
	 * during reset.  Stolen from pci_reset_function()
	 */
	pci_write_config_word(pdev, PCI_COMMAND, PCI_COMMAND_INTX_DISABLE);

	/*
	 * Try to reset the device.  The success of this is dependent on
	 * being able to lock the device, which is not always possible.
	 */
	if (vdev->reset_works) {
		int ret = pci_try_reset_function(pdev);
		if (ret)
			pr_warn("%s: Failed to reset device %s (%d)\n",
				__func__, dev_name(&pdev->dev), ret);
	}

	pci_restore_state(pdev);
}

static void vfio_pci_release(void *device_data)
{
	struct vfio_pci_device *vdev = device_data;

	if (atomic_dec_and_test(&vdev->refcnt))
		vfio_pci_disable(vdev);

	module_put(THIS_MODULE);
}

static int vfio_pci_open(void *device_data)
{
	struct vfio_pci_device *vdev = device_data;

	if (!try_module_get(THIS_MODULE))
		return -ENODEV;

	if (atomic_inc_return(&vdev->refcnt) == 1) {
		int ret = vfio_pci_enable(vdev);
		if (ret) {
			module_put(THIS_MODULE);
			return ret;
		}
	}

	return 0;
}

static int vfio_pci_get_irq_count(struct vfio_pci_device *vdev, int irq_type)
{
	if (irq_type == VFIO_PCI_INTX_IRQ_INDEX) {
		u8 pin;
		pci_read_config_byte(vdev->pdev, PCI_INTERRUPT_PIN, &pin);
		if (pin)
			return 1;

	} else if (irq_type == VFIO_PCI_MSI_IRQ_INDEX) {
		u8 pos;
		u16 flags;

		pos = vdev->pdev->msi_cap;
		if (pos) {
			pci_read_config_word(vdev->pdev,
					     pos + PCI_MSI_FLAGS, &flags);
			return 1 << ((flags & PCI_MSI_FLAGS_QMASK) >> 1);
		}
	} else if (irq_type == VFIO_PCI_MSIX_IRQ_INDEX) {
		u8 pos;
		u16 flags;

		pos = vdev->pdev->msix_cap;
		if (pos) {
			pci_read_config_word(vdev->pdev,
					     pos + PCI_MSIX_FLAGS, &flags);

			return (flags & PCI_MSIX_FLAGS_QSIZE) + 1;
		}
	} else if (irq_type == VFIO_PCI_ERR_IRQ_INDEX)
		if (pci_is_pcie(vdev->pdev))
			return 1;

	return 0;
}

static int vfio_pci_count_devs(struct pci_dev *pdev, void *data)
{
	(*(int *)data)++;
	return 0;
}

struct vfio_pci_fill_info {
	int max;
	int cur;
	struct vfio_pci_dependent_device *devices;
};

static int vfio_pci_fill_devs(struct pci_dev *pdev, void *data)
{
	struct vfio_pci_fill_info *fill = data;
	struct iommu_group *iommu_group;

	if (fill->cur == fill->max)
		return -EAGAIN; /* Something changed, try again */

	iommu_group = iommu_group_get(&pdev->dev);
	if (!iommu_group)
		return -EPERM; /* Cannot reset non-isolated devices */

	fill->devices[fill->cur].group_id = iommu_group_id(iommu_group);
	fill->devices[fill->cur].segment = pci_domain_nr(pdev->bus);
	fill->devices[fill->cur].bus = pdev->bus->number;
	fill->devices[fill->cur].devfn = pdev->devfn;
	fill->cur++;
	iommu_group_put(iommu_group);
	return 0;
}

struct vfio_pci_group_entry {
	struct vfio_group *group;
	int id;
};

struct vfio_pci_group_info {
	int count;
	struct vfio_pci_group_entry *groups;
};

static int vfio_pci_validate_devs(struct pci_dev *pdev, void *data)
{
	struct vfio_pci_group_info *info = data;
	struct iommu_group *group;
	int id, i;

	group = iommu_group_get(&pdev->dev);
	if (!group)
		return -EPERM;

	id = iommu_group_id(group);

	for (i = 0; i < info->count; i++)
		if (info->groups[i].id == id)
			break;

	iommu_group_put(group);

	return (i == info->count) ? -EINVAL : 0;
}

static bool vfio_pci_dev_below_slot(struct pci_dev *pdev, struct pci_slot *slot)
{
	for (; pdev; pdev = pdev->bus->self)
		if (pdev->bus == slot->bus)
			return (pdev->slot == slot);
	return false;
}

struct vfio_pci_walk_info {
	int (*fn)(struct pci_dev *, void *data);
	void *data;
	struct pci_dev *pdev;
	bool slot;
	int ret;
};

static int vfio_pci_walk_wrapper(struct pci_dev *pdev, void *data)
{
	struct vfio_pci_walk_info *walk = data;

	if (!walk->slot || vfio_pci_dev_below_slot(pdev, walk->pdev->slot))
		walk->ret = walk->fn(pdev, walk->data);

	return walk->ret;
}

static int vfio_pci_for_each_slot_or_bus(struct pci_dev *pdev,
					 int (*fn)(struct pci_dev *,
						   void *data), void *data,
					 bool slot)
{
	struct vfio_pci_walk_info walk = {
		.fn = fn, .data = data, .pdev = pdev, .slot = slot, .ret = 0,
	};

	pci_walk_bus(pdev->bus, vfio_pci_walk_wrapper, &walk);

	return walk.ret;
}

static long vfio_pci_ioctl(void *device_data,
			   unsigned int cmd, unsigned long arg)
{
	struct vfio_pci_device *vdev = device_data;
	unsigned long minsz;

	if (cmd == VFIO_DEVICE_GET_INFO) {
		struct vfio_device_info info;

		minsz = offsetofend(struct vfio_device_info, num_irqs);

		if (copy_from_user(&info, (void __user *)arg, minsz))
			return -EFAULT;

		if (info.argsz < minsz)
			return -EINVAL;

		info.flags = VFIO_DEVICE_FLAGS_PCI;

		if (vdev->reset_works)
			info.flags |= VFIO_DEVICE_FLAGS_RESET;

		info.num_regions = VFIO_PCI_NUM_REGIONS;
		info.num_irqs = VFIO_PCI_NUM_IRQS;

		return copy_to_user((void __user *)arg, &info, minsz);

	} else if (cmd == VFIO_DEVICE_GET_REGION_INFO) {
		struct pci_dev *pdev = vdev->pdev;
		struct vfio_region_info info;

		minsz = offsetofend(struct vfio_region_info, offset);

		if (copy_from_user(&info, (void __user *)arg, minsz))
			return -EFAULT;

		if (info.argsz < minsz)
			return -EINVAL;

		switch (info.index) {
		case VFIO_PCI_CONFIG_REGION_INDEX:
			info.offset = VFIO_PCI_INDEX_TO_OFFSET(info.index);
			info.size = pdev->cfg_size;
			info.flags = VFIO_REGION_INFO_FLAG_READ |
				     VFIO_REGION_INFO_FLAG_WRITE;
			break;
		case VFIO_PCI_BAR0_REGION_INDEX ... VFIO_PCI_BAR5_REGION_INDEX:
			info.offset = VFIO_PCI_INDEX_TO_OFFSET(info.index);
			info.size = pci_resource_len(pdev, info.index);
			if (!info.size) {
				info.flags = 0;
				break;
			}

			info.flags = VFIO_REGION_INFO_FLAG_READ |
				     VFIO_REGION_INFO_FLAG_WRITE;
			if (pci_resource_flags(pdev, info.index) &
			    IORESOURCE_MEM && info.size >= PAGE_SIZE)
				info.flags |= VFIO_REGION_INFO_FLAG_MMAP;
			break;
		case VFIO_PCI_ROM_REGION_INDEX:
		{
			void __iomem *io;
			size_t size;

			info.offset = VFIO_PCI_INDEX_TO_OFFSET(info.index);
			info.flags = 0;

			/* Report the BAR size, not the ROM size */
			info.size = pci_resource_len(pdev, info.index);
			if (!info.size)
				break;

			/* Is it really there? */
			io = pci_map_rom(pdev, &size);
			if (!io || !size) {
				info.size = 0;
				break;
			}
			pci_unmap_rom(pdev, io);

			info.flags = VFIO_REGION_INFO_FLAG_READ;
			break;
		}
		case VFIO_PCI_VGA_REGION_INDEX:
			if (!vdev->has_vga)
				return -EINVAL;

			info.offset = VFIO_PCI_INDEX_TO_OFFSET(info.index);
			info.size = 0xc0000;
			info.flags = VFIO_REGION_INFO_FLAG_READ |
				     VFIO_REGION_INFO_FLAG_WRITE;

			break;
		default:
			return -EINVAL;
		}

		return copy_to_user((void __user *)arg, &info, minsz);

	} else if (cmd == VFIO_DEVICE_GET_IRQ_INFO) {
		struct vfio_irq_info info;

		minsz = offsetofend(struct vfio_irq_info, count);

		if (copy_from_user(&info, (void __user *)arg, minsz))
			return -EFAULT;

		if (info.argsz < minsz || info.index >= VFIO_PCI_NUM_IRQS)
			return -EINVAL;

		switch (info.index) {
		case VFIO_PCI_INTX_IRQ_INDEX ... VFIO_PCI_MSIX_IRQ_INDEX:
			break;
		case VFIO_PCI_ERR_IRQ_INDEX:
			if (pci_is_pcie(vdev->pdev))
				break;
		/* pass thru to return error */
		default:
			return -EINVAL;
		}

		info.flags = VFIO_IRQ_INFO_EVENTFD;

		info.count = vfio_pci_get_irq_count(vdev, info.index);

		if (info.index == VFIO_PCI_INTX_IRQ_INDEX)
			info.flags |= (VFIO_IRQ_INFO_MASKABLE |
				       VFIO_IRQ_INFO_AUTOMASKED);
		else
			info.flags |= VFIO_IRQ_INFO_NORESIZE;

		return copy_to_user((void __user *)arg, &info, minsz);

	} else if (cmd == VFIO_DEVICE_SET_IRQS) {
		struct vfio_irq_set hdr;
		u8 *data = NULL;
		int ret = 0;

		minsz = offsetofend(struct vfio_irq_set, count);

		if (copy_from_user(&hdr, (void __user *)arg, minsz))
			return -EFAULT;

		if (hdr.argsz < minsz || hdr.index >= VFIO_PCI_NUM_IRQS ||
		    hdr.flags & ~(VFIO_IRQ_SET_DATA_TYPE_MASK |
				  VFIO_IRQ_SET_ACTION_TYPE_MASK))
			return -EINVAL;

		if (!(hdr.flags & VFIO_IRQ_SET_DATA_NONE)) {
			size_t size;
			int max = vfio_pci_get_irq_count(vdev, hdr.index);

			if (hdr.flags & VFIO_IRQ_SET_DATA_BOOL)
				size = sizeof(uint8_t);
			else if (hdr.flags & VFIO_IRQ_SET_DATA_EVENTFD)
				size = sizeof(int32_t);
			else
				return -EINVAL;

			if (hdr.argsz - minsz < hdr.count * size ||
			    hdr.start >= max || hdr.start + hdr.count > max)
				return -EINVAL;

			data = memdup_user((void __user *)(arg + minsz),
					   hdr.count * size);
			if (IS_ERR(data))
				return PTR_ERR(data);
		}

		mutex_lock(&vdev->igate);

		ret = vfio_pci_set_irqs_ioctl(vdev, hdr.flags, hdr.index,
					      hdr.start, hdr.count, data);

		mutex_unlock(&vdev->igate);
		kfree(data);

		return ret;

	} else if (cmd == VFIO_DEVICE_RESET) {
		return vdev->reset_works ?
			pci_try_reset_function(vdev->pdev) : -EINVAL;

	} else if (cmd == VFIO_DEVICE_GET_PCI_HOT_RESET_INFO) {
		struct vfio_pci_hot_reset_info hdr;
		struct vfio_pci_fill_info fill = { 0 };
		struct vfio_pci_dependent_device *devices = NULL;
		bool slot = false;
		int ret = 0;

		minsz = offsetofend(struct vfio_pci_hot_reset_info, count);

		if (copy_from_user(&hdr, (void __user *)arg, minsz))
			return -EFAULT;

		if (hdr.argsz < minsz)
			return -EINVAL;

		hdr.flags = 0;

		/* Can we do a slot or bus reset or neither? */
		if (!pci_probe_reset_slot(vdev->pdev->slot))
			slot = true;
		else if (pci_probe_reset_bus(vdev->pdev->bus))
			return -ENODEV;

		/* How many devices are affected? */
		ret = vfio_pci_for_each_slot_or_bus(vdev->pdev,
						    vfio_pci_count_devs,
						    &fill.max, slot);
		if (ret)
			return ret;

		WARN_ON(!fill.max); /* Should always be at least one */

		/*
		 * If there's enough space, fill it now, otherwise return
		 * -ENOSPC and the number of devices affected.
		 */
		if (hdr.argsz < sizeof(hdr) + (fill.max * sizeof(*devices))) {
			ret = -ENOSPC;
			hdr.count = fill.max;
			goto reset_info_exit;
		}

		devices = kcalloc(fill.max, sizeof(*devices), GFP_KERNEL);
		if (!devices)
			return -ENOMEM;

		fill.devices = devices;

		ret = vfio_pci_for_each_slot_or_bus(vdev->pdev,
						    vfio_pci_fill_devs,
						    &fill, slot);

		/*
		 * If a device was removed between counting and filling,
		 * we may come up short of fill.max.  If a device was
		 * added, we'll have a return of -EAGAIN above.
		 */
		if (!ret)
			hdr.count = fill.cur;

reset_info_exit:
		if (copy_to_user((void __user *)arg, &hdr, minsz))
			ret = -EFAULT;

		if (!ret) {
			if (copy_to_user((void __user *)(arg + minsz), devices,
					 hdr.count * sizeof(*devices)))
				ret = -EFAULT;
		}

		kfree(devices);
		return ret;

	} else if (cmd == VFIO_DEVICE_PCI_HOT_RESET) {
		struct vfio_pci_hot_reset hdr;
		int32_t *group_fds;
		struct vfio_pci_group_entry *groups;
		struct vfio_pci_group_info info;
		bool slot = false;
		int i, count = 0, ret = 0;

		minsz = offsetofend(struct vfio_pci_hot_reset, count);

		if (copy_from_user(&hdr, (void __user *)arg, minsz))
			return -EFAULT;

		if (hdr.argsz < minsz || hdr.flags)
			return -EINVAL;

		/* Can we do a slot or bus reset or neither? */
		if (!pci_probe_reset_slot(vdev->pdev->slot))
			slot = true;
		else if (pci_probe_reset_bus(vdev->pdev->bus))
			return -ENODEV;

		/*
		 * We can't let userspace give us an arbitrarily large
		 * buffer to copy, so verify how many we think there
		 * could be.  Note groups can have multiple devices so
		 * one group per device is the max.
		 */
		ret = vfio_pci_for_each_slot_or_bus(vdev->pdev,
						    vfio_pci_count_devs,
						    &count, slot);
		if (ret)
			return ret;

		/* Somewhere between 1 and count is OK */
		if (!hdr.count || hdr.count > count)
			return -EINVAL;

		group_fds = kcalloc(hdr.count, sizeof(*group_fds), GFP_KERNEL);
		groups = kcalloc(hdr.count, sizeof(*groups), GFP_KERNEL);
		if (!group_fds || !groups) {
			kfree(group_fds);
			kfree(groups);
			return -ENOMEM;
		}

		if (copy_from_user(group_fds, (void __user *)(arg + minsz),
				   hdr.count * sizeof(*group_fds))) {
			kfree(group_fds);
			kfree(groups);
			return -EFAULT;
		}

		/*
		 * For each group_fd, get the group through the vfio external
		 * user interface and store the group and iommu ID.  This
		 * ensures the group is held across the reset.
		 */
		for (i = 0; i < hdr.count; i++) {
			struct vfio_group *group;
			struct fd f = fdget(group_fds[i]);
			if (!f.file) {
				ret = -EBADF;
				break;
			}

			group = vfio_group_get_external_user(f.file);
			fdput(f);
			if (IS_ERR(group)) {
				ret = PTR_ERR(group);
				break;
			}

			groups[i].group = group;
			groups[i].id = vfio_external_user_iommu_id(group);
		}

		kfree(group_fds);

		/* release reference to groups on error */
		if (ret)
			goto hot_reset_release;

		info.count = hdr.count;
		info.groups = groups;

		/*
		 * Test whether all the affected devices are contained
		 * by the set of groups provided by the user.
		 */
		ret = vfio_pci_for_each_slot_or_bus(vdev->pdev,
						    vfio_pci_validate_devs,
						    &info, slot);
		if (!ret)
			/* User has access, do the reset */
			ret = slot ? pci_try_reset_slot(vdev->pdev->slot) :
				     pci_try_reset_bus(vdev->pdev->bus);

hot_reset_release:
		for (i--; i >= 0; i--)
			vfio_group_put_external_user(groups[i].group);

		kfree(groups);
		return ret;
	}

	return -ENOTTY;
}

static ssize_t vfio_pci_rw(void *device_data, char __user *buf,
			   size_t count, loff_t *ppos, bool iswrite)
{
	unsigned int index = VFIO_PCI_OFFSET_TO_INDEX(*ppos);
	struct vfio_pci_device *vdev = device_data;

	if (index >= VFIO_PCI_NUM_REGIONS)
		return -EINVAL;

	switch (index) {
	case VFIO_PCI_CONFIG_REGION_INDEX:
		return vfio_pci_config_rw(vdev, buf, count, ppos, iswrite);

	case VFIO_PCI_ROM_REGION_INDEX:
		if (iswrite)
			return -EINVAL;
		return vfio_pci_bar_rw(vdev, buf, count, ppos, false);

	case VFIO_PCI_BAR0_REGION_INDEX ... VFIO_PCI_BAR5_REGION_INDEX:
		return vfio_pci_bar_rw(vdev, buf, count, ppos, iswrite);

	case VFIO_PCI_VGA_REGION_INDEX:
		return vfio_pci_vga_rw(vdev, buf, count, ppos, iswrite);
	}

	return -EINVAL;
}

static ssize_t vfio_pci_read(void *device_data, char __user *buf,
			     size_t count, loff_t *ppos)
{
	if (!count)
		return 0;

	return vfio_pci_rw(device_data, buf, count, ppos, false);
}

static ssize_t vfio_pci_write(void *device_data, const char __user *buf,
			      size_t count, loff_t *ppos)
{
	if (!count)
		return 0;

	return vfio_pci_rw(device_data, (char __user *)buf, count, ppos, true);
}

static int vfio_pci_mmap(void *device_data, struct vm_area_struct *vma)
{
	struct vfio_pci_device *vdev = device_data;
	struct pci_dev *pdev = vdev->pdev;
	unsigned int index;
	u64 phys_len, req_len, pgoff, req_start;
	int ret;

	index = vma->vm_pgoff >> (VFIO_PCI_OFFSET_SHIFT - PAGE_SHIFT);

	if (vma->vm_end < vma->vm_start)
		return -EINVAL;
	if ((vma->vm_flags & VM_SHARED) == 0)
		return -EINVAL;
	if (index >= VFIO_PCI_ROM_REGION_INDEX)
		return -EINVAL;
	if (!(pci_resource_flags(pdev, index) & IORESOURCE_MEM))
		return -EINVAL;

	phys_len = pci_resource_len(pdev, index);
	req_len = vma->vm_end - vma->vm_start;
	pgoff = vma->vm_pgoff &
		((1U << (VFIO_PCI_OFFSET_SHIFT - PAGE_SHIFT)) - 1);
	req_start = pgoff << PAGE_SHIFT;

	if (phys_len < PAGE_SIZE || req_start + req_len > phys_len)
		return -EINVAL;

	if (index == vdev->msix_bar) {
		/*
		 * Disallow mmaps overlapping the MSI-X table; users don't
		 * get to touch this directly.  We could find somewhere
		 * else to map the overlap, but page granularity is only
		 * a recommendation, not a requirement, so the user needs
		 * to know which bits are real.  Requiring them to mmap
		 * around the table makes that clear.
		 */

		/* If neither entirely above nor below, then it overlaps */
		if (!(req_start >= vdev->msix_offset + vdev->msix_size ||
		      req_start + req_len <= vdev->msix_offset))
			return -EINVAL;
	}

	/*
	 * Even though we don't make use of the barmap for the mmap,
	 * we need to request the region and the barmap tracks that.
	 */
	if (!vdev->barmap[index]) {
		ret = pci_request_selected_regions(pdev,
						   1 << index, "vfio-pci");
		if (ret)
			return ret;

		vdev->barmap[index] = pci_iomap(pdev, index, 0);
	}

	vma->vm_private_data = vdev;
	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
	vma->vm_pgoff = (pci_resource_start(pdev, index) >> PAGE_SHIFT) + pgoff;

	return remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,
			       req_len, vma->vm_page_prot);
}

static const struct vfio_device_ops vfio_pci_ops = {
	.name		= "vfio-pci",
	.open		= vfio_pci_open,
	.release	= vfio_pci_release,
	.ioctl		= vfio_pci_ioctl,
	.read		= vfio_pci_read,
	.write		= vfio_pci_write,
	.mmap		= vfio_pci_mmap,
};

static int vfio_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
{
	u8 type;
	struct vfio_pci_device *vdev;
	struct iommu_group *group;
	int ret;

	pci_read_config_byte(pdev, PCI_HEADER_TYPE, &type);
	if ((type & PCI_HEADER_TYPE) != PCI_HEADER_TYPE_NORMAL)
		return -EINVAL;

	group = iommu_group_get(&pdev->dev);
	if (!group)
		return -EINVAL;

	vdev = kzalloc(sizeof(*vdev), GFP_KERNEL);
	if (!vdev) {
		iommu_group_put(group);
		return -ENOMEM;
	}

	vdev->pdev = pdev;
	vdev->irq_type = VFIO_PCI_NUM_IRQS;
	mutex_init(&vdev->igate);
	spin_lock_init(&vdev->irqlock);
	atomic_set(&vdev->refcnt, 0);

	ret = vfio_add_group_dev(&pdev->dev, &vfio_pci_ops, vdev);
	if (ret) {
		iommu_group_put(group);
		kfree(vdev);
	}

	return ret;
}

static void vfio_pci_remove(struct pci_dev *pdev)
{
	struct vfio_pci_device *vdev;

	vdev = vfio_del_group_dev(&pdev->dev);
	if (!vdev)
		return;

	iommu_group_put(pdev->dev.iommu_group);
	kfree(vdev);
}

static pci_ers_result_t vfio_pci_aer_err_detected(struct pci_dev *pdev,
						  pci_channel_state_t state)
{
	struct vfio_pci_device *vdev;
	struct vfio_device *device;

	device = vfio_device_get_from_dev(&pdev->dev);
	if (device == NULL)
		return PCI_ERS_RESULT_DISCONNECT;

	vdev = vfio_device_data(device);
	if (vdev == NULL) {
		vfio_device_put(device);
		return PCI_ERS_RESULT_DISCONNECT;
	}

	mutex_lock(&vdev->igate);

	if (vdev->err_trigger)
		eventfd_signal(vdev->err_trigger, 1);

	mutex_unlock(&vdev->igate);

	vfio_device_put(device);

	return PCI_ERS_RESULT_CAN_RECOVER;
}

static struct pci_error_handlers vfio_err_handlers = {
	.error_detected = vfio_pci_aer_err_detected,
};

static struct pci_driver vfio_pci_driver = {
	.name		= "vfio-pci",
	.id_table	= NULL, /* only dynamic ids */
	.probe		= vfio_pci_probe,
	.remove		= vfio_pci_remove,
	.err_handler	= &vfio_err_handlers,
};

static void __exit vfio_pci_cleanup(void)
{
	pci_unregister_driver(&vfio_pci_driver);
	vfio_pci_virqfd_exit();
	vfio_pci_uninit_perm_bits();
}

static int __init vfio_pci_init(void)
{
	int ret;

	/* Allocate shared config space permision data used by all devices */
	ret = vfio_pci_init_perm_bits();
	if (ret)
		return ret;

	/* Start the virqfd cleanup handler */
	ret = vfio_pci_virqfd_init();
	if (ret)
		goto out_virqfd;

	/* Register and scan for devices */
	ret = pci_register_driver(&vfio_pci_driver);
	if (ret)
		goto out_driver;

	return 0;

out_driver:
	vfio_pci_virqfd_exit();
out_virqfd:
	vfio_pci_uninit_perm_bits();
	return ret;
}

module_init(vfio_pci_init);
module_exit(vfio_pci_cleanup);

MODULE_VERSION(DRIVER_VERSION);
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);