Commit | Line | Data |
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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 | ||
9d830d47 AW |
63 | static 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 | ||
e0f0bbc5 AW |
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 | */ | |
86 | static 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) { | |
9d830d47 AW |
95 | if (!kvm_vfio_group_is_coherent(kvg->vfio_group)) { |
96 | noncoherent = true; | |
97 | break; | |
98 | } | |
e0f0bbc5 AW |
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 | ||
ec53500f AW |
113 | static 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; | |
e81d1ad3 | 118 | int32_t __user *argp = (int32_t __user *)(unsigned long)arg; |
ec53500f AW |
119 | struct fd f; |
120 | int32_t fd; | |
121 | int ret; | |
122 | ||
123 | switch (attr) { | |
124 | case KVM_DEV_VFIO_GROUP_ADD: | |
e81d1ad3 | 125 | if (get_user(fd, argp)) |
ec53500f AW |
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 | mutex_unlock(&kv->lock); | |
159 | ||
e0f0bbc5 AW |
160 | kvm_vfio_update_coherency(dev); |
161 | ||
ec53500f AW |
162 | return 0; |
163 | ||
164 | case KVM_DEV_VFIO_GROUP_DEL: | |
e81d1ad3 | 165 | if (get_user(fd, argp)) |
ec53500f AW |
166 | return -EFAULT; |
167 | ||
168 | f = fdget(fd); | |
169 | if (!f.file) | |
170 | return -EBADF; | |
171 | ||
172 | vfio_group = kvm_vfio_group_get_external_user(f.file); | |
173 | fdput(f); | |
174 | ||
175 | if (IS_ERR(vfio_group)) | |
176 | return PTR_ERR(vfio_group); | |
177 | ||
178 | ret = -ENOENT; | |
179 | ||
180 | mutex_lock(&kv->lock); | |
181 | ||
182 | list_for_each_entry(kvg, &kv->group_list, node) { | |
183 | if (kvg->vfio_group != vfio_group) | |
184 | continue; | |
185 | ||
186 | list_del(&kvg->node); | |
187 | kvm_vfio_group_put_external_user(kvg->vfio_group); | |
188 | kfree(kvg); | |
189 | ret = 0; | |
190 | break; | |
191 | } | |
192 | ||
193 | mutex_unlock(&kv->lock); | |
194 | ||
195 | kvm_vfio_group_put_external_user(vfio_group); | |
196 | ||
e0f0bbc5 AW |
197 | kvm_vfio_update_coherency(dev); |
198 | ||
ec53500f AW |
199 | return ret; |
200 | } | |
201 | ||
202 | return -ENXIO; | |
203 | } | |
204 | ||
205 | static int kvm_vfio_set_attr(struct kvm_device *dev, | |
206 | struct kvm_device_attr *attr) | |
207 | { | |
208 | switch (attr->group) { | |
209 | case KVM_DEV_VFIO_GROUP: | |
210 | return kvm_vfio_set_group(dev, attr->attr, attr->addr); | |
211 | } | |
212 | ||
213 | return -ENXIO; | |
214 | } | |
215 | ||
216 | static int kvm_vfio_has_attr(struct kvm_device *dev, | |
217 | struct kvm_device_attr *attr) | |
218 | { | |
219 | switch (attr->group) { | |
220 | case KVM_DEV_VFIO_GROUP: | |
221 | switch (attr->attr) { | |
222 | case KVM_DEV_VFIO_GROUP_ADD: | |
223 | case KVM_DEV_VFIO_GROUP_DEL: | |
224 | return 0; | |
225 | } | |
226 | ||
227 | break; | |
228 | } | |
229 | ||
230 | return -ENXIO; | |
231 | } | |
232 | ||
233 | static void kvm_vfio_destroy(struct kvm_device *dev) | |
234 | { | |
235 | struct kvm_vfio *kv = dev->private; | |
236 | struct kvm_vfio_group *kvg, *tmp; | |
237 | ||
238 | list_for_each_entry_safe(kvg, tmp, &kv->group_list, node) { | |
239 | kvm_vfio_group_put_external_user(kvg->vfio_group); | |
240 | list_del(&kvg->node); | |
241 | kfree(kvg); | |
242 | } | |
243 | ||
e0f0bbc5 AW |
244 | kvm_vfio_update_coherency(dev); |
245 | ||
ec53500f AW |
246 | kfree(kv); |
247 | kfree(dev); /* alloc by kvm_ioctl_create_device, free by .destroy */ | |
248 | } | |
249 | ||
80ce1639 WD |
250 | static int kvm_vfio_create(struct kvm_device *dev, u32 type); |
251 | ||
252 | static struct kvm_device_ops kvm_vfio_ops = { | |
253 | .name = "kvm-vfio", | |
254 | .create = kvm_vfio_create, | |
255 | .destroy = kvm_vfio_destroy, | |
256 | .set_attr = kvm_vfio_set_attr, | |
257 | .has_attr = kvm_vfio_has_attr, | |
258 | }; | |
259 | ||
ec53500f AW |
260 | static int kvm_vfio_create(struct kvm_device *dev, u32 type) |
261 | { | |
262 | struct kvm_device *tmp; | |
263 | struct kvm_vfio *kv; | |
264 | ||
265 | /* Only one VFIO "device" per VM */ | |
266 | list_for_each_entry(tmp, &dev->kvm->devices, vm_node) | |
267 | if (tmp->ops == &kvm_vfio_ops) | |
268 | return -EBUSY; | |
269 | ||
270 | kv = kzalloc(sizeof(*kv), GFP_KERNEL); | |
271 | if (!kv) | |
272 | return -ENOMEM; | |
273 | ||
274 | INIT_LIST_HEAD(&kv->group_list); | |
275 | mutex_init(&kv->lock); | |
276 | ||
277 | dev->private = kv; | |
278 | ||
279 | return 0; | |
280 | } | |
281 | ||
3c3c29fd | 282 | int kvm_vfio_ops_init(void) |
80ce1639 WD |
283 | { |
284 | return kvm_register_device_ops(&kvm_vfio_ops, KVM_DEV_TYPE_VFIO); | |
285 | } | |
571ee1b6 WL |
286 | |
287 | void kvm_vfio_ops_exit(void) | |
288 | { | |
289 | kvm_unregister_device_ops(KVM_DEV_TYPE_VFIO); | |
290 | } |