summaryrefslogtreecommitdiffstats
path: root/drivers/vfio/pci/vfio_pci.c
blob: 09d2e3ffd6fcefe6c7a7cf6c8c13c755b1c1fde5 (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
/*
 * 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/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) {
		pci_load_and_free_saved_state(pdev, &vdev->pci_saved_state);
		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);

	if (vdev->reset_works)
		__pci_reset_function(pdev);

	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);
		}
	} 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;
		}
	}

	return 0;
}

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;

		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_reset_function(vdev->pdev) : -EINVAL;

	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_flags |= VM_IO | VM_DONTEXPAND | VM_DONTDUMP;
	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 struct pci_driver vfio_pci_driver = {
	.name		= "vfio-pci",
	.id_table	= NULL, /* only dynamic ids */
	.probe		= vfio_pci_probe,
	.remove		= vfio_pci_remove,
};

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);