summaryrefslogtreecommitdiff
path: root/drivers/vfio/pci/vfio_pci_rdwr.c
blob: 0120d8324a402490f489bae6468fbe6f8b65af4d (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
// SPDX-License-Identifier: GPL-2.0-only
/*
 * VFIO PCI I/O Port & MMIO access
 *
 * Copyright (C) 2012 Red Hat, Inc.  All rights reserved.
 *     Author: Alex Williamson <alex.williamson@redhat.com>
 *
 * Derived from original vfio:
 * Copyright 2010 Cisco Systems, Inc.  All rights reserved.
 * Author: Tom Lyon, pugs@cisco.com
 */

#include <linux/fs.h>
#include <linux/pci.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include <linux/vfio.h>
#include <linux/vgaarb.h>

#include "vfio_pci_private.h"

#ifdef __LITTLE_ENDIAN
#define vfio_ioread64	ioread64
#define vfio_iowrite64	iowrite64
#define vfio_ioread32	ioread32
#define vfio_iowrite32	iowrite32
#define vfio_ioread16	ioread16
#define vfio_iowrite16	iowrite16
#else
#define vfio_ioread64	ioread64be
#define vfio_iowrite64	iowrite64be
#define vfio_ioread32	ioread32be
#define vfio_iowrite32	iowrite32be
#define vfio_ioread16	ioread16be
#define vfio_iowrite16	iowrite16be
#endif
#define vfio_ioread8	ioread8
#define vfio_iowrite8	iowrite8

/*
 * Read or write from an __iomem region (MMIO or I/O port) with an excluded
 * range which is inaccessible.  The excluded range drops writes and fills
 * reads with -1.  This is intended for handling MSI-X vector tables and
 * leftover space for ROM BARs.
 */
static ssize_t do_io_rw(void __iomem *io, char __user *buf,
			loff_t off, size_t count, size_t x_start,
			size_t x_end, bool iswrite)
{
	ssize_t done = 0;

	while (count) {
		size_t fillable, filled;

		if (off < x_start)
			fillable = min(count, (size_t)(x_start - off));
		else if (off >= x_end)
			fillable = count;
		else
			fillable = 0;

		if (fillable >= 4 && !(off % 4)) {
			u32 val;

			if (iswrite) {
				if (copy_from_user(&val, buf, 4))
					return -EFAULT;

				vfio_iowrite32(val, io + off);
			} else {
				val = vfio_ioread32(io + off);

				if (copy_to_user(buf, &val, 4))
					return -EFAULT;
			}

			filled = 4;
		} else if (fillable >= 2 && !(off % 2)) {
			u16 val;

			if (iswrite) {
				if (copy_from_user(&val, buf, 2))
					return -EFAULT;

				vfio_iowrite16(val, io + off);
			} else {
				val = vfio_ioread16(io + off);

				if (copy_to_user(buf, &val, 2))
					return -EFAULT;
			}

			filled = 2;
		} else if (fillable) {
			u8 val;

			if (iswrite) {
				if (copy_from_user(&val, buf, 1))
					return -EFAULT;

				vfio_iowrite8(val, io + off);
			} else {
				val = vfio_ioread8(io + off);

				if (copy_to_user(buf, &val, 1))
					return -EFAULT;
			}

			filled = 1;
		} else {
			/* Fill reads with -1, drop writes */
			filled = min(count, (size_t)(x_end - off));
			if (!iswrite) {
				u8 val = 0xFF;
				size_t i;

				for (i = 0; i < filled; i++)
					if (copy_to_user(buf + i, &val, 1))
						return -EFAULT;
			}
		}

		count -= filled;
		done += filled;
		off += filled;
		buf += filled;
	}

	return done;
}

static int vfio_pci_setup_barmap(struct vfio_pci_device *vdev, int bar)
{
	struct pci_dev *pdev = vdev->pdev;
	int ret;
	void __iomem *io;

	if (vdev->barmap[bar])
		return 0;

	ret = pci_request_selected_regions(pdev, 1 << bar, "vfio");
	if (ret)
		return ret;

	io = pci_iomap(pdev, bar, 0);
	if (!io) {
		pci_release_selected_regions(pdev, 1 << bar);
		return -ENOMEM;
	}

	vdev->barmap[bar] = io;

	return 0;
}

ssize_t vfio_pci_bar_rw(struct vfio_pci_device *vdev, char __user *buf,
			size_t count, loff_t *ppos, bool iswrite)
{
	struct pci_dev *pdev = vdev->pdev;
	loff_t pos = *ppos & VFIO_PCI_OFFSET_MASK;
	int bar = VFIO_PCI_OFFSET_TO_INDEX(*ppos);
	size_t x_start = 0, x_end = 0;
	resource_size_t end;
	void __iomem *io;
	ssize_t done;

	if (pci_resource_start(pdev, bar))
		end = pci_resource_len(pdev, bar);
	else if (bar == PCI_ROM_RESOURCE &&
		 pdev->resource[bar].flags & IORESOURCE_ROM_SHADOW)
		end = 0x20000;
	else
		return -EINVAL;

	if (pos >= end)
		return -EINVAL;

	count = min(count, (size_t)(end - pos));

	if (bar == PCI_ROM_RESOURCE) {
		/*
		 * The ROM can fill less space than the BAR, so we start the
		 * excluded range at the end of the actual ROM.  This makes
		 * filling large ROM BARs much faster.
		 */
		io = pci_map_rom(pdev, &x_start);
		if (!io)
			return -ENOMEM;
		x_end = end;
	} else {
		int ret = vfio_pci_setup_barmap(vdev, bar);
		if (ret)
			return ret;

		io = vdev->barmap[bar];
	}

	if (bar == vdev->msix_bar) {
		x_start = vdev->msix_offset;
		x_end = vdev->msix_offset + vdev->msix_size;
	}

	done = do_io_rw(io, buf, pos, count, x_start, x_end, iswrite);

	if (done >= 0)
		*ppos += done;

	if (bar == PCI_ROM_RESOURCE)
		pci_unmap_rom(pdev, io);

	return done;
}

ssize_t vfio_pci_vga_rw(struct vfio_pci_device *vdev, char __user *buf,
			       size_t count, loff_t *ppos, bool iswrite)
{
	int ret;
	loff_t off, pos = *ppos & VFIO_PCI_OFFSET_MASK;
	void __iomem *iomem = NULL;
	unsigned int rsrc;
	bool is_ioport;
	ssize_t done;

	if (!vdev->has_vga)
		return -EINVAL;

	if (pos > 0xbfffful)
		return -EINVAL;

	switch ((u32)pos) {
	case 0xa0000 ... 0xbffff:
		count = min(count, (size_t)(0xc0000 - pos));
		iomem = ioremap_nocache(0xa0000, 0xbffff - 0xa0000 + 1);
		off = pos - 0xa0000;
		rsrc = VGA_RSRC_LEGACY_MEM;
		is_ioport = false;
		break;
	case 0x3b0 ... 0x3bb:
		count = min(count, (size_t)(0x3bc - pos));
		iomem = ioport_map(0x3b0, 0x3bb - 0x3b0 + 1);
		off = pos - 0x3b0;
		rsrc = VGA_RSRC_LEGACY_IO;
		is_ioport = true;
		break;
	case 0x3c0 ... 0x3df:
		count = min(count, (size_t)(0x3e0 - pos));
		iomem = ioport_map(0x3c0, 0x3df - 0x3c0 + 1);
		off = pos - 0x3c0;
		rsrc = VGA_RSRC_LEGACY_IO;
		is_ioport = true;
		break;
	default:
		return -EINVAL;
	}

	if (!iomem)
		return -ENOMEM;

	ret = vga_get_interruptible(vdev->pdev, rsrc);
	if (ret) {
		is_ioport ? ioport_unmap(iomem) : iounmap(iomem);
		return ret;
	}

	done = do_io_rw(iomem, buf, off, count, 0, 0, iswrite);

	vga_put(vdev->pdev, rsrc);

	is_ioport ? ioport_unmap(iomem) : iounmap(iomem);

	if (done >= 0)
		*ppos += done;

	return done;
}

static int vfio_pci_ioeventfd_handler(void *opaque, void *unused)
{
	struct vfio_pci_ioeventfd *ioeventfd = opaque;

	switch (ioeventfd->count) {
	case 1:
		vfio_iowrite8(ioeventfd->data, ioeventfd->addr);
		break;
	case 2:
		vfio_iowrite16(ioeventfd->data, ioeventfd->addr);
		break;
	case 4:
		vfio_iowrite32(ioeventfd->data, ioeventfd->addr);
		break;
#ifdef iowrite64
	case 8:
		vfio_iowrite64(ioeventfd->data, ioeventfd->addr);
		break;
#endif
	}

	return 0;
}

long vfio_pci_ioeventfd(struct vfio_pci_device *vdev, loff_t offset,
			uint64_t data, int count, int fd)
{
	struct pci_dev *pdev = vdev->pdev;
	loff_t pos = offset & VFIO_PCI_OFFSET_MASK;
	int ret, bar = VFIO_PCI_OFFSET_TO_INDEX(offset);
	struct vfio_pci_ioeventfd *ioeventfd;

	/* Only support ioeventfds into BARs */
	if (bar > VFIO_PCI_BAR5_REGION_INDEX)
		return -EINVAL;

	if (pos + count > pci_resource_len(pdev, bar))
		return -EINVAL;

	/* Disallow ioeventfds working around MSI-X table writes */
	if (bar == vdev->msix_bar &&
	    !(pos + count <= vdev->msix_offset ||
	      pos >= vdev->msix_offset + vdev->msix_size))
		return -EINVAL;

#ifndef iowrite64
	if (count == 8)
		return -EINVAL;
#endif

	ret = vfio_pci_setup_barmap(vdev, bar);
	if (ret)
		return ret;

	mutex_lock(&vdev->ioeventfds_lock);

	list_for_each_entry(ioeventfd, &vdev->ioeventfds_list, next) {
		if (ioeventfd->pos == pos && ioeventfd->bar == bar &&
		    ioeventfd->data == data && ioeventfd->count == count) {
			if (fd == -1) {
				vfio_virqfd_disable(&ioeventfd->virqfd);
				list_del(&ioeventfd->next);
				vdev->ioeventfds_nr--;
				kfree(ioeventfd);
				ret = 0;
			} else
				ret = -EEXIST;

			goto out_unlock;
		}
	}

	if (fd < 0) {
		ret = -ENODEV;
		goto out_unlock;
	}

	if (vdev->ioeventfds_nr >= VFIO_PCI_IOEVENTFD_MAX) {
		ret = -ENOSPC;
		goto out_unlock;
	}

	ioeventfd = kzalloc(sizeof(*ioeventfd), GFP_KERNEL);
	if (!ioeventfd) {
		ret = -ENOMEM;
		goto out_unlock;
	}

	ioeventfd->addr = vdev->barmap[bar] + pos;
	ioeventfd->data = data;
	ioeventfd->pos = pos;
	ioeventfd->bar = bar;
	ioeventfd->count = count;

	ret = vfio_virqfd_enable(ioeventfd, vfio_pci_ioeventfd_handler,
				 NULL, NULL, &ioeventfd->virqfd, fd);
	if (ret) {
		kfree(ioeventfd);
		goto out_unlock;
	}

	list_add(&ioeventfd->next, &vdev->ioeventfds_list);
	vdev->ioeventfds_nr++;

out_unlock:
	mutex_unlock(&vdev->ioeventfds_lock);

	return ret;
}