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1/*
2 * VFIO-KVM bridge pseudo device
3 *
4 * Copyright (C) 2013 Red Hat, Inc. All rights reserved.
5 * Author: Alex Williamson <alex.williamson@redhat.com>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 */
11
12#include <linux/errno.h>
13#include <linux/file.h>
14#include <linux/kvm_host.h>
15#include <linux/list.h>
16#include <linux/module.h>
17#include <linux/mutex.h>
18#include <linux/slab.h>
19#include <linux/uaccess.h>
20#include <linux/vfio.h>
21
22struct kvm_vfio_group {
23 struct list_head node;
24 struct vfio_group *vfio_group;
25};
26
27struct kvm_vfio {
28 struct list_head group_list;
29 struct mutex lock;
30 bool noncoherent;
31};
32
33static struct vfio_group *kvm_vfio_group_get_external_user(struct file *filep)
34{
35 struct vfio_group *vfio_group;
36 struct vfio_group *(*fn)(struct file *);
37
38 fn = symbol_get(vfio_group_get_external_user);
39 if (!fn)
40 return ERR_PTR(-EINVAL);
41
42 vfio_group = fn(filep);
43
44 symbol_put(vfio_group_get_external_user);
45
46 return vfio_group;
47}
48
49static void kvm_vfio_group_put_external_user(struct vfio_group *vfio_group)
50{
51 void (*fn)(struct vfio_group *);
52
53 fn = symbol_get(vfio_group_put_external_user);
54 if (!fn)
55 return;
56
57 fn(vfio_group);
58
59 symbol_put(vfio_group_put_external_user);
60}
61
62static bool kvm_vfio_group_is_coherent(struct vfio_group *vfio_group)
63{
64 long (*fn)(struct vfio_group *, unsigned long);
65 long ret;
66
67 fn = symbol_get(vfio_external_check_extension);
68 if (!fn)
69 return false;
70
71 ret = fn(vfio_group, VFIO_DMA_CC_IOMMU);
72
73 symbol_put(vfio_external_check_extension);
74
75 return ret > 0;
76}
77
78/*
79 * Groups can use the same or different IOMMU domains. If the same then
80 * adding a new group may change the coherency of groups we've previously
81 * been told about. We don't want to care about any of that so we retest
82 * each group and bail as soon as we find one that's noncoherent. This
83 * means we only ever [un]register_noncoherent_dma once for the whole device.
84 */
85static void kvm_vfio_update_coherency(struct kvm_device *dev)
86{
87 struct kvm_vfio *kv = dev->private;
88 bool noncoherent = false;
89 struct kvm_vfio_group *kvg;
90
91 mutex_lock(&kv->lock);
92
93 list_for_each_entry(kvg, &kv->group_list, node) {
94 if (!kvm_vfio_group_is_coherent(kvg->vfio_group)) {
95 noncoherent = true;
96 break;
97 }
98 }
99
100 if (noncoherent != kv->noncoherent) {
101 kv->noncoherent = noncoherent;
102
103 if (kv->noncoherent)
104 kvm_arch_register_noncoherent_dma(dev->kvm);
105 else
106 kvm_arch_unregister_noncoherent_dma(dev->kvm);
107 }
108
109 mutex_unlock(&kv->lock);
110}
111
112static int kvm_vfio_set_group(struct kvm_device *dev, long attr, u64 arg)
113{
114 struct kvm_vfio *kv = dev->private;
115 struct vfio_group *vfio_group;
116 struct kvm_vfio_group *kvg;
117 int32_t __user *argp = (int32_t __user *)(unsigned long)arg;
118 struct fd f;
119 int32_t fd;
120 int ret;
121
122 switch (attr) {
123 case KVM_DEV_VFIO_GROUP_ADD:
124 if (get_user(fd, argp))
125 return -EFAULT;
126
127 f = fdget(fd);
128 if (!f.file)
129 return -EBADF;
130
131 vfio_group = kvm_vfio_group_get_external_user(f.file);
132 fdput(f);
133
134 if (IS_ERR(vfio_group))
135 return PTR_ERR(vfio_group);
136
137 mutex_lock(&kv->lock);
138
139 list_for_each_entry(kvg, &kv->group_list, node) {
140 if (kvg->vfio_group == vfio_group) {
141 mutex_unlock(&kv->lock);
142 kvm_vfio_group_put_external_user(vfio_group);
143 return -EEXIST;
144 }
145 }
146
147 kvg = kzalloc(sizeof(*kvg), GFP_KERNEL);
148 if (!kvg) {
149 mutex_unlock(&kv->lock);
150 kvm_vfio_group_put_external_user(vfio_group);
151 return -ENOMEM;
152 }
153
154 list_add_tail(&kvg->node, &kv->group_list);
155 kvg->vfio_group = vfio_group;
156
157 mutex_unlock(&kv->lock);
158
159 kvm_vfio_update_coherency(dev);
160
161 return 0;
162
163 case KVM_DEV_VFIO_GROUP_DEL:
164 if (get_user(fd, argp))
165 return -EFAULT;
166
167 f = fdget(fd);
168 if (!f.file)
169 return -EBADF;
170
171 vfio_group = kvm_vfio_group_get_external_user(f.file);
172 fdput(f);
173
174 if (IS_ERR(vfio_group))
175 return PTR_ERR(vfio_group);
176
177 ret = -ENOENT;
178
179 mutex_lock(&kv->lock);
180
181 list_for_each_entry(kvg, &kv->group_list, node) {
182 if (kvg->vfio_group != vfio_group)
183 continue;
184
185 list_del(&kvg->node);
186 kvm_vfio_group_put_external_user(kvg->vfio_group);
187 kfree(kvg);
188 ret = 0;
189 break;
190 }
191
192 mutex_unlock(&kv->lock);
193
194 kvm_vfio_group_put_external_user(vfio_group);
195
196 kvm_vfio_update_coherency(dev);
197
198 return ret;
199 }
200
201 return -ENXIO;
202}
203
204static int kvm_vfio_set_attr(struct kvm_device *dev,
205 struct kvm_device_attr *attr)
206{
207 switch (attr->group) {
208 case KVM_DEV_VFIO_GROUP:
209 return kvm_vfio_set_group(dev, attr->attr, attr->addr);
210 }
211
212 return -ENXIO;
213}
214
215static int kvm_vfio_has_attr(struct kvm_device *dev,
216 struct kvm_device_attr *attr)
217{
218 switch (attr->group) {
219 case KVM_DEV_VFIO_GROUP:
220 switch (attr->attr) {
221 case KVM_DEV_VFIO_GROUP_ADD:
222 case KVM_DEV_VFIO_GROUP_DEL:
223 return 0;
224 }
225
226 break;
227 }
228
229 return -ENXIO;
230}
231
232static void kvm_vfio_destroy(struct kvm_device *dev)
233{
234 struct kvm_vfio *kv = dev->private;
235 struct kvm_vfio_group *kvg, *tmp;
236
237 list_for_each_entry_safe(kvg, tmp, &kv->group_list, node) {
238 kvm_vfio_group_put_external_user(kvg->vfio_group);
239 list_del(&kvg->node);
240 kfree(kvg);
241 }
242
243 kvm_vfio_update_coherency(dev);
244
245 kfree(kv);
246 kfree(dev); /* alloc by kvm_ioctl_create_device, free by .destroy */
247}
248
249static int kvm_vfio_create(struct kvm_device *dev, u32 type)
250{
251 struct kvm_device *tmp;
252 struct kvm_vfio *kv;
253
254 /* Only one VFIO "device" per VM */
255 list_for_each_entry(tmp, &dev->kvm->devices, vm_node)
256 if (tmp->ops == &kvm_vfio_ops)
257 return -EBUSY;
258
259 kv = kzalloc(sizeof(*kv), GFP_KERNEL);
260 if (!kv)
261 return -ENOMEM;
262
263 INIT_LIST_HEAD(&kv->group_list);
264 mutex_init(&kv->lock);
265
266 dev->private = kv;
267
268 return 0;
269}
270
271struct kvm_device_ops kvm_vfio_ops = {
272 .name = "kvm-vfio",
273 .create = kvm_vfio_create,
274 .destroy = kvm_vfio_destroy,
275 .set_attr = kvm_vfio_set_attr,
276 .has_attr = kvm_vfio_has_attr,
277};
1/*
2 * VFIO-KVM bridge pseudo device
3 *
4 * Copyright (C) 2013 Red Hat, Inc. All rights reserved.
5 * Author: Alex Williamson <alex.williamson@redhat.com>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 */
11
12#include <linux/errno.h>
13#include <linux/file.h>
14#include <linux/kvm_host.h>
15#include <linux/list.h>
16#include <linux/module.h>
17#include <linux/mutex.h>
18#include <linux/slab.h>
19#include <linux/uaccess.h>
20#include <linux/vfio.h>
21#include "vfio.h"
22
23struct kvm_vfio_group {
24 struct list_head node;
25 struct vfio_group *vfio_group;
26};
27
28struct kvm_vfio {
29 struct list_head group_list;
30 struct mutex lock;
31 bool noncoherent;
32};
33
34static struct vfio_group *kvm_vfio_group_get_external_user(struct file *filep)
35{
36 struct vfio_group *vfio_group;
37 struct vfio_group *(*fn)(struct file *);
38
39 fn = symbol_get(vfio_group_get_external_user);
40 if (!fn)
41 return ERR_PTR(-EINVAL);
42
43 vfio_group = fn(filep);
44
45 symbol_put(vfio_group_get_external_user);
46
47 return vfio_group;
48}
49
50static void kvm_vfio_group_put_external_user(struct vfio_group *vfio_group)
51{
52 void (*fn)(struct vfio_group *);
53
54 fn = symbol_get(vfio_group_put_external_user);
55 if (!fn)
56 return;
57
58 fn(vfio_group);
59
60 symbol_put(vfio_group_put_external_user);
61}
62
63static bool kvm_vfio_group_is_coherent(struct vfio_group *vfio_group)
64{
65 long (*fn)(struct vfio_group *, unsigned long);
66 long ret;
67
68 fn = symbol_get(vfio_external_check_extension);
69 if (!fn)
70 return false;
71
72 ret = fn(vfio_group, VFIO_DMA_CC_IOMMU);
73
74 symbol_put(vfio_external_check_extension);
75
76 return ret > 0;
77}
78
79/*
80 * Groups can use the same or different IOMMU domains. If the same then
81 * adding a new group may change the coherency of groups we've previously
82 * been told about. We don't want to care about any of that so we retest
83 * each group and bail as soon as we find one that's noncoherent. This
84 * means we only ever [un]register_noncoherent_dma once for the whole device.
85 */
86static void kvm_vfio_update_coherency(struct kvm_device *dev)
87{
88 struct kvm_vfio *kv = dev->private;
89 bool noncoherent = false;
90 struct kvm_vfio_group *kvg;
91
92 mutex_lock(&kv->lock);
93
94 list_for_each_entry(kvg, &kv->group_list, node) {
95 if (!kvm_vfio_group_is_coherent(kvg->vfio_group)) {
96 noncoherent = true;
97 break;
98 }
99 }
100
101 if (noncoherent != kv->noncoherent) {
102 kv->noncoherent = noncoherent;
103
104 if (kv->noncoherent)
105 kvm_arch_register_noncoherent_dma(dev->kvm);
106 else
107 kvm_arch_unregister_noncoherent_dma(dev->kvm);
108 }
109
110 mutex_unlock(&kv->lock);
111}
112
113static int kvm_vfio_set_group(struct kvm_device *dev, long attr, u64 arg)
114{
115 struct kvm_vfio *kv = dev->private;
116 struct vfio_group *vfio_group;
117 struct kvm_vfio_group *kvg;
118 int32_t __user *argp = (int32_t __user *)(unsigned long)arg;
119 struct fd f;
120 int32_t fd;
121 int ret;
122
123 switch (attr) {
124 case KVM_DEV_VFIO_GROUP_ADD:
125 if (get_user(fd, argp))
126 return -EFAULT;
127
128 f = fdget(fd);
129 if (!f.file)
130 return -EBADF;
131
132 vfio_group = kvm_vfio_group_get_external_user(f.file);
133 fdput(f);
134
135 if (IS_ERR(vfio_group))
136 return PTR_ERR(vfio_group);
137
138 mutex_lock(&kv->lock);
139
140 list_for_each_entry(kvg, &kv->group_list, node) {
141 if (kvg->vfio_group == vfio_group) {
142 mutex_unlock(&kv->lock);
143 kvm_vfio_group_put_external_user(vfio_group);
144 return -EEXIST;
145 }
146 }
147
148 kvg = kzalloc(sizeof(*kvg), GFP_KERNEL);
149 if (!kvg) {
150 mutex_unlock(&kv->lock);
151 kvm_vfio_group_put_external_user(vfio_group);
152 return -ENOMEM;
153 }
154
155 list_add_tail(&kvg->node, &kv->group_list);
156 kvg->vfio_group = vfio_group;
157
158 kvm_arch_start_assignment(dev->kvm);
159
160 mutex_unlock(&kv->lock);
161
162 kvm_vfio_update_coherency(dev);
163
164 return 0;
165
166 case KVM_DEV_VFIO_GROUP_DEL:
167 if (get_user(fd, argp))
168 return -EFAULT;
169
170 f = fdget(fd);
171 if (!f.file)
172 return -EBADF;
173
174 vfio_group = kvm_vfio_group_get_external_user(f.file);
175 fdput(f);
176
177 if (IS_ERR(vfio_group))
178 return PTR_ERR(vfio_group);
179
180 ret = -ENOENT;
181
182 mutex_lock(&kv->lock);
183
184 list_for_each_entry(kvg, &kv->group_list, node) {
185 if (kvg->vfio_group != vfio_group)
186 continue;
187
188 list_del(&kvg->node);
189 kvm_vfio_group_put_external_user(kvg->vfio_group);
190 kfree(kvg);
191 ret = 0;
192 break;
193 }
194
195 kvm_arch_end_assignment(dev->kvm);
196
197 mutex_unlock(&kv->lock);
198
199 kvm_vfio_group_put_external_user(vfio_group);
200
201 kvm_vfio_update_coherency(dev);
202
203 return ret;
204 }
205
206 return -ENXIO;
207}
208
209static int kvm_vfio_set_attr(struct kvm_device *dev,
210 struct kvm_device_attr *attr)
211{
212 switch (attr->group) {
213 case KVM_DEV_VFIO_GROUP:
214 return kvm_vfio_set_group(dev, attr->attr, attr->addr);
215 }
216
217 return -ENXIO;
218}
219
220static int kvm_vfio_has_attr(struct kvm_device *dev,
221 struct kvm_device_attr *attr)
222{
223 switch (attr->group) {
224 case KVM_DEV_VFIO_GROUP:
225 switch (attr->attr) {
226 case KVM_DEV_VFIO_GROUP_ADD:
227 case KVM_DEV_VFIO_GROUP_DEL:
228 return 0;
229 }
230
231 break;
232 }
233
234 return -ENXIO;
235}
236
237static void kvm_vfio_destroy(struct kvm_device *dev)
238{
239 struct kvm_vfio *kv = dev->private;
240 struct kvm_vfio_group *kvg, *tmp;
241
242 list_for_each_entry_safe(kvg, tmp, &kv->group_list, node) {
243 kvm_vfio_group_put_external_user(kvg->vfio_group);
244 list_del(&kvg->node);
245 kfree(kvg);
246 kvm_arch_end_assignment(dev->kvm);
247 }
248
249 kvm_vfio_update_coherency(dev);
250
251 kfree(kv);
252 kfree(dev); /* alloc by kvm_ioctl_create_device, free by .destroy */
253}
254
255static int kvm_vfio_create(struct kvm_device *dev, u32 type);
256
257static struct kvm_device_ops kvm_vfio_ops = {
258 .name = "kvm-vfio",
259 .create = kvm_vfio_create,
260 .destroy = kvm_vfio_destroy,
261 .set_attr = kvm_vfio_set_attr,
262 .has_attr = kvm_vfio_has_attr,
263};
264
265static int kvm_vfio_create(struct kvm_device *dev, u32 type)
266{
267 struct kvm_device *tmp;
268 struct kvm_vfio *kv;
269
270 /* Only one VFIO "device" per VM */
271 list_for_each_entry(tmp, &dev->kvm->devices, vm_node)
272 if (tmp->ops == &kvm_vfio_ops)
273 return -EBUSY;
274
275 kv = kzalloc(sizeof(*kv), GFP_KERNEL);
276 if (!kv)
277 return -ENOMEM;
278
279 INIT_LIST_HEAD(&kv->group_list);
280 mutex_init(&kv->lock);
281
282 dev->private = kv;
283
284 return 0;
285}
286
287int kvm_vfio_ops_init(void)
288{
289 return kvm_register_device_ops(&kvm_vfio_ops, KVM_DEV_TYPE_VFIO);
290}
291
292void kvm_vfio_ops_exit(void)
293{
294 kvm_unregister_device_ops(KVM_DEV_TYPE_VFIO);
295}