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ec53500f AW |
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> | |
3c3c29fd | 21 | #include "vfio.h" |
ec53500f AW |
22 | |
23 | struct kvm_vfio_group { | |
24 | struct list_head node; | |
25 | struct vfio_group *vfio_group; | |
26 | }; | |
27 | ||
28 | struct kvm_vfio { | |
29 | struct list_head group_list; | |
30 | struct mutex lock; | |
e0f0bbc5 | 31 | bool noncoherent; |
ec53500f AW |
32 | }; |
33 | ||
34 | static 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 | ||
50 | static 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 | ||
2fc1bec1 JS |
63 | static void kvm_vfio_group_set_kvm(struct vfio_group *group, struct kvm *kvm) |
64 | { | |
65 | void (*fn)(struct vfio_group *, struct kvm *); | |
66 | ||
67 | fn = symbol_get(vfio_group_set_kvm); | |
68 | if (!fn) | |
69 | return; | |
70 | ||
71 | fn(group, kvm); | |
72 | ||
73 | symbol_put(vfio_group_set_kvm); | |
74 | } | |
75 | ||
9d830d47 AW |
76 | static bool kvm_vfio_group_is_coherent(struct vfio_group *vfio_group) |
77 | { | |
78 | long (*fn)(struct vfio_group *, unsigned long); | |
79 | long ret; | |
80 | ||
81 | fn = symbol_get(vfio_external_check_extension); | |
82 | if (!fn) | |
83 | return false; | |
84 | ||
85 | ret = fn(vfio_group, VFIO_DMA_CC_IOMMU); | |
86 | ||
87 | symbol_put(vfio_external_check_extension); | |
88 | ||
89 | return ret > 0; | |
90 | } | |
91 | ||
e0f0bbc5 AW |
92 | /* |
93 | * Groups can use the same or different IOMMU domains. If the same then | |
94 | * adding a new group may change the coherency of groups we've previously | |
95 | * been told about. We don't want to care about any of that so we retest | |
96 | * each group and bail as soon as we find one that's noncoherent. This | |
97 | * means we only ever [un]register_noncoherent_dma once for the whole device. | |
98 | */ | |
99 | static void kvm_vfio_update_coherency(struct kvm_device *dev) | |
100 | { | |
101 | struct kvm_vfio *kv = dev->private; | |
102 | bool noncoherent = false; | |
103 | struct kvm_vfio_group *kvg; | |
104 | ||
105 | mutex_lock(&kv->lock); | |
106 | ||
107 | list_for_each_entry(kvg, &kv->group_list, node) { | |
9d830d47 AW |
108 | if (!kvm_vfio_group_is_coherent(kvg->vfio_group)) { |
109 | noncoherent = true; | |
110 | break; | |
111 | } | |
e0f0bbc5 AW |
112 | } |
113 | ||
114 | if (noncoherent != kv->noncoherent) { | |
115 | kv->noncoherent = noncoherent; | |
116 | ||
117 | if (kv->noncoherent) | |
118 | kvm_arch_register_noncoherent_dma(dev->kvm); | |
119 | else | |
120 | kvm_arch_unregister_noncoherent_dma(dev->kvm); | |
121 | } | |
122 | ||
123 | mutex_unlock(&kv->lock); | |
124 | } | |
125 | ||
ec53500f AW |
126 | static int kvm_vfio_set_group(struct kvm_device *dev, long attr, u64 arg) |
127 | { | |
128 | struct kvm_vfio *kv = dev->private; | |
129 | struct vfio_group *vfio_group; | |
130 | struct kvm_vfio_group *kvg; | |
e81d1ad3 | 131 | int32_t __user *argp = (int32_t __user *)(unsigned long)arg; |
ec53500f AW |
132 | struct fd f; |
133 | int32_t fd; | |
134 | int ret; | |
135 | ||
136 | switch (attr) { | |
137 | case KVM_DEV_VFIO_GROUP_ADD: | |
e81d1ad3 | 138 | if (get_user(fd, argp)) |
ec53500f AW |
139 | return -EFAULT; |
140 | ||
141 | f = fdget(fd); | |
142 | if (!f.file) | |
143 | return -EBADF; | |
144 | ||
145 | vfio_group = kvm_vfio_group_get_external_user(f.file); | |
146 | fdput(f); | |
147 | ||
148 | if (IS_ERR(vfio_group)) | |
149 | return PTR_ERR(vfio_group); | |
150 | ||
151 | mutex_lock(&kv->lock); | |
152 | ||
153 | list_for_each_entry(kvg, &kv->group_list, node) { | |
154 | if (kvg->vfio_group == vfio_group) { | |
155 | mutex_unlock(&kv->lock); | |
156 | kvm_vfio_group_put_external_user(vfio_group); | |
157 | return -EEXIST; | |
158 | } | |
159 | } | |
160 | ||
161 | kvg = kzalloc(sizeof(*kvg), GFP_KERNEL); | |
162 | if (!kvg) { | |
163 | mutex_unlock(&kv->lock); | |
164 | kvm_vfio_group_put_external_user(vfio_group); | |
165 | return -ENOMEM; | |
166 | } | |
167 | ||
168 | list_add_tail(&kvg->node, &kv->group_list); | |
169 | kvg->vfio_group = vfio_group; | |
170 | ||
5544eb9b PB |
171 | kvm_arch_start_assignment(dev->kvm); |
172 | ||
ec53500f AW |
173 | mutex_unlock(&kv->lock); |
174 | ||
2fc1bec1 JS |
175 | kvm_vfio_group_set_kvm(vfio_group, dev->kvm); |
176 | ||
e0f0bbc5 AW |
177 | kvm_vfio_update_coherency(dev); |
178 | ||
ec53500f AW |
179 | return 0; |
180 | ||
181 | case KVM_DEV_VFIO_GROUP_DEL: | |
e81d1ad3 | 182 | if (get_user(fd, argp)) |
ec53500f AW |
183 | return -EFAULT; |
184 | ||
185 | f = fdget(fd); | |
186 | if (!f.file) | |
187 | return -EBADF; | |
188 | ||
189 | vfio_group = kvm_vfio_group_get_external_user(f.file); | |
190 | fdput(f); | |
191 | ||
192 | if (IS_ERR(vfio_group)) | |
193 | return PTR_ERR(vfio_group); | |
194 | ||
195 | ret = -ENOENT; | |
196 | ||
197 | mutex_lock(&kv->lock); | |
198 | ||
199 | list_for_each_entry(kvg, &kv->group_list, node) { | |
200 | if (kvg->vfio_group != vfio_group) | |
201 | continue; | |
202 | ||
203 | list_del(&kvg->node); | |
204 | kvm_vfio_group_put_external_user(kvg->vfio_group); | |
205 | kfree(kvg); | |
206 | ret = 0; | |
207 | break; | |
208 | } | |
209 | ||
5544eb9b PB |
210 | kvm_arch_end_assignment(dev->kvm); |
211 | ||
ec53500f AW |
212 | mutex_unlock(&kv->lock); |
213 | ||
2fc1bec1 JS |
214 | kvm_vfio_group_set_kvm(vfio_group, NULL); |
215 | ||
ec53500f AW |
216 | kvm_vfio_group_put_external_user(vfio_group); |
217 | ||
e0f0bbc5 AW |
218 | kvm_vfio_update_coherency(dev); |
219 | ||
ec53500f AW |
220 | return ret; |
221 | } | |
222 | ||
223 | return -ENXIO; | |
224 | } | |
225 | ||
226 | static int kvm_vfio_set_attr(struct kvm_device *dev, | |
227 | struct kvm_device_attr *attr) | |
228 | { | |
229 | switch (attr->group) { | |
230 | case KVM_DEV_VFIO_GROUP: | |
231 | return kvm_vfio_set_group(dev, attr->attr, attr->addr); | |
232 | } | |
233 | ||
234 | return -ENXIO; | |
235 | } | |
236 | ||
237 | static int kvm_vfio_has_attr(struct kvm_device *dev, | |
238 | struct kvm_device_attr *attr) | |
239 | { | |
240 | switch (attr->group) { | |
241 | case KVM_DEV_VFIO_GROUP: | |
242 | switch (attr->attr) { | |
243 | case KVM_DEV_VFIO_GROUP_ADD: | |
244 | case KVM_DEV_VFIO_GROUP_DEL: | |
245 | return 0; | |
246 | } | |
247 | ||
248 | break; | |
249 | } | |
250 | ||
251 | return -ENXIO; | |
252 | } | |
253 | ||
254 | static void kvm_vfio_destroy(struct kvm_device *dev) | |
255 | { | |
256 | struct kvm_vfio *kv = dev->private; | |
257 | struct kvm_vfio_group *kvg, *tmp; | |
258 | ||
259 | list_for_each_entry_safe(kvg, tmp, &kv->group_list, node) { | |
2fc1bec1 | 260 | kvm_vfio_group_set_kvm(kvg->vfio_group, NULL); |
ec53500f AW |
261 | kvm_vfio_group_put_external_user(kvg->vfio_group); |
262 | list_del(&kvg->node); | |
263 | kfree(kvg); | |
5544eb9b | 264 | kvm_arch_end_assignment(dev->kvm); |
ec53500f AW |
265 | } |
266 | ||
e0f0bbc5 AW |
267 | kvm_vfio_update_coherency(dev); |
268 | ||
ec53500f AW |
269 | kfree(kv); |
270 | kfree(dev); /* alloc by kvm_ioctl_create_device, free by .destroy */ | |
271 | } | |
272 | ||
80ce1639 WD |
273 | static int kvm_vfio_create(struct kvm_device *dev, u32 type); |
274 | ||
275 | static struct kvm_device_ops kvm_vfio_ops = { | |
276 | .name = "kvm-vfio", | |
277 | .create = kvm_vfio_create, | |
278 | .destroy = kvm_vfio_destroy, | |
279 | .set_attr = kvm_vfio_set_attr, | |
280 | .has_attr = kvm_vfio_has_attr, | |
281 | }; | |
282 | ||
ec53500f AW |
283 | static int kvm_vfio_create(struct kvm_device *dev, u32 type) |
284 | { | |
285 | struct kvm_device *tmp; | |
286 | struct kvm_vfio *kv; | |
287 | ||
288 | /* Only one VFIO "device" per VM */ | |
289 | list_for_each_entry(tmp, &dev->kvm->devices, vm_node) | |
290 | if (tmp->ops == &kvm_vfio_ops) | |
291 | return -EBUSY; | |
292 | ||
293 | kv = kzalloc(sizeof(*kv), GFP_KERNEL); | |
294 | if (!kv) | |
295 | return -ENOMEM; | |
296 | ||
297 | INIT_LIST_HEAD(&kv->group_list); | |
298 | mutex_init(&kv->lock); | |
299 | ||
300 | dev->private = kv; | |
301 | ||
302 | return 0; | |
303 | } | |
304 | ||
3c3c29fd | 305 | int kvm_vfio_ops_init(void) |
80ce1639 WD |
306 | { |
307 | return kvm_register_device_ops(&kvm_vfio_ops, KVM_DEV_TYPE_VFIO); | |
308 | } | |
571ee1b6 WL |
309 | |
310 | void kvm_vfio_ops_exit(void) | |
311 | { | |
312 | kvm_unregister_device_ops(KVM_DEV_TYPE_VFIO); | |
313 | } |