aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/vfio/pci/vfio_pci_rdwr.c
blob: f72323ef618fbd99ce88d0c99480d165b94e2f42 (plain) (blame)
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
/*
 * VFIO PCI I/O Port & MMIO access
 *
 * 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/fs.h>
#include <linux/pci.h>
#include <linux/uaccess.h>
#include <linux/io.h>

#include "vfio_pci_private.h"

/* I/O Port BAR access */
ssize_t vfio_pci_io_readwrite(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);
	void __iomem *io;
	size_t done = 0;

	if (!pci_resource_start(pdev, bar))
		return -EINVAL;

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

	if (!vdev->barmap[bar]) {
		int ret;

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

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

		if (!vdev->barmap[bar]) {
			pci_release_selected_regions(pdev, 1 << bar);
			return -EINVAL;
		}
	}

	io = vdev->barmap[bar];

	while (count) {
		int filled;

		if (count >= 3 && !(pos % 4)) {
			__le32 val;

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

				iowrite32(le32_to_cpu(val), io + pos);
			} else {
				val = cpu_to_le32(ioread32(io + pos));

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

			filled = 4;

		} else if ((pos % 2) == 0 && count >= 2) {
			__le16 val;

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

				iowrite16(le16_to_cpu(val), io + pos);
			} else {
				val = cpu_to_le16(ioread16(io + pos));

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

			filled = 2;
		} else {
			u8 val;

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

				iowrite8(val, io + pos);
			} else {
				val = ioread8(io + pos);

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

			filled = 1;
		}

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

	*ppos += done;

	return done;
}

/*
 * MMIO BAR access
 * We handle two excluded ranges here as well, if the user tries to read
 * the ROM beyond what PCI tells us is available or the MSI-X table region,
 * we return 0xFF and writes are dropped.
 */
ssize_t vfio_pci_mem_readwrite(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);
	void __iomem *io;
	resource_size_t end;
	size_t done = 0;
	size_t x_start = 0, x_end = 0; /* excluded range */

	if (!pci_resource_start(pdev, bar))
		return -EINVAL;

	end = pci_resource_len(pdev, bar);

	if (pos > end)
		return -EINVAL;

	if (pos == end)
		return 0;

	if (pos + count > end)
		count = end - pos;

	if (bar == PCI_ROM_RESOURCE) {
		io = pci_map_rom(pdev, &x_start);
		x_end = end;
	} else {
		if (!vdev->barmap[bar]) {
			int ret;

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

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

			if (!vdev->barmap[bar]) {
				pci_release_selected_regions(pdev, 1 << bar);
				return -EINVAL;
			}
		}

		io = vdev->barmap[bar];

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

	if (!io)
		return -EINVAL;

	while (count) {
		size_t fillable, filled;

		if (pos < x_start)
			fillable = x_start - pos;
		else if (pos >= x_end)
			fillable = end - pos;
		else
			fillable = 0;

		if (fillable >= 4 && !(pos % 4) && (count >= 4)) {
			__le32 val;

			if (iswrite) {
				if (copy_from_user(&val, buf, 4))
					goto out;

				iowrite32(le32_to_cpu(val), io + pos);
			} else {
				val = cpu_to_le32(ioread32(io + pos));

				if (copy_to_user(buf, &val, 4))
					goto out;
			}

			filled = 4;
		} else if (fillable >= 2 && !(pos % 2) && (count >= 2)) {
			__le16 val;

			if (iswrite) {
				if (copy_from_user(&val, buf, 2))
					goto out;

				iowrite16(le16_to_cpu(val), io + pos);
			} else {
				val = cpu_to_le16(ioread16(io + pos));

				if (copy_to_user(buf, &val, 2))
					goto out;
			}

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

			if (iswrite) {
				if (copy_from_user(&val, buf, 1))
					goto out;

				iowrite8(val, io + pos);
			} else {
				val = ioread8(io + pos);

				if (copy_to_user(buf, &val, 1))
					goto out;
			}

			filled = 1;
		} else {
			/* Drop writes, fill reads with FF */
			filled = min((size_t)(x_end - pos), count);
			if (!iswrite) {
				char val = 0xFF;
				size_t i;

				for (i = 0; i < filled; i++) {
					if (put_user(val, buf + i))
						goto out;
				}
			}

		}

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

	*ppos += done;

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

	return count ? -EFAULT : done;
}