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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> | |
21 | ||
22 | struct kvm_vfio_group { | |
23 | struct list_head node; | |
24 | struct vfio_group *vfio_group; | |
25 | }; | |
26 | ||
27 | struct kvm_vfio { | |
28 | struct list_head group_list; | |
29 | struct mutex lock; | |
e0f0bbc5 | 30 | bool noncoherent; |
ec53500f AW |
31 | }; |
32 | ||
33 | static 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 | ||
49 | static 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 | ||
e0f0bbc5 AW |
62 | /* |
63 | * Groups can use the same or different IOMMU domains. If the same then | |
64 | * adding a new group may change the coherency of groups we've previously | |
65 | * been told about. We don't want to care about any of that so we retest | |
66 | * each group and bail as soon as we find one that's noncoherent. This | |
67 | * means we only ever [un]register_noncoherent_dma once for the whole device. | |
68 | */ | |
69 | static void kvm_vfio_update_coherency(struct kvm_device *dev) | |
70 | { | |
71 | struct kvm_vfio *kv = dev->private; | |
72 | bool noncoherent = false; | |
73 | struct kvm_vfio_group *kvg; | |
74 | ||
75 | mutex_lock(&kv->lock); | |
76 | ||
77 | list_for_each_entry(kvg, &kv->group_list, node) { | |
78 | /* | |
79 | * TODO: We need an interface to check the coherency of | |
80 | * the IOMMU domain this group is using. For now, assume | |
81 | * it's always noncoherent. | |
82 | */ | |
83 | noncoherent = true; | |
84 | break; | |
85 | } | |
86 | ||
87 | if (noncoherent != kv->noncoherent) { | |
88 | kv->noncoherent = noncoherent; | |
89 | ||
90 | if (kv->noncoherent) | |
91 | kvm_arch_register_noncoherent_dma(dev->kvm); | |
92 | else | |
93 | kvm_arch_unregister_noncoherent_dma(dev->kvm); | |
94 | } | |
95 | ||
96 | mutex_unlock(&kv->lock); | |
97 | } | |
98 | ||
ec53500f AW |
99 | static int kvm_vfio_set_group(struct kvm_device *dev, long attr, u64 arg) |
100 | { | |
101 | struct kvm_vfio *kv = dev->private; | |
102 | struct vfio_group *vfio_group; | |
103 | struct kvm_vfio_group *kvg; | |
e81d1ad3 | 104 | int32_t __user *argp = (int32_t __user *)(unsigned long)arg; |
ec53500f AW |
105 | struct fd f; |
106 | int32_t fd; | |
107 | int ret; | |
108 | ||
109 | switch (attr) { | |
110 | case KVM_DEV_VFIO_GROUP_ADD: | |
e81d1ad3 | 111 | if (get_user(fd, argp)) |
ec53500f AW |
112 | return -EFAULT; |
113 | ||
114 | f = fdget(fd); | |
115 | if (!f.file) | |
116 | return -EBADF; | |
117 | ||
118 | vfio_group = kvm_vfio_group_get_external_user(f.file); | |
119 | fdput(f); | |
120 | ||
121 | if (IS_ERR(vfio_group)) | |
122 | return PTR_ERR(vfio_group); | |
123 | ||
124 | mutex_lock(&kv->lock); | |
125 | ||
126 | list_for_each_entry(kvg, &kv->group_list, node) { | |
127 | if (kvg->vfio_group == vfio_group) { | |
128 | mutex_unlock(&kv->lock); | |
129 | kvm_vfio_group_put_external_user(vfio_group); | |
130 | return -EEXIST; | |
131 | } | |
132 | } | |
133 | ||
134 | kvg = kzalloc(sizeof(*kvg), GFP_KERNEL); | |
135 | if (!kvg) { | |
136 | mutex_unlock(&kv->lock); | |
137 | kvm_vfio_group_put_external_user(vfio_group); | |
138 | return -ENOMEM; | |
139 | } | |
140 | ||
141 | list_add_tail(&kvg->node, &kv->group_list); | |
142 | kvg->vfio_group = vfio_group; | |
143 | ||
144 | mutex_unlock(&kv->lock); | |
145 | ||
e0f0bbc5 AW |
146 | kvm_vfio_update_coherency(dev); |
147 | ||
ec53500f AW |
148 | return 0; |
149 | ||
150 | case KVM_DEV_VFIO_GROUP_DEL: | |
e81d1ad3 | 151 | if (get_user(fd, argp)) |
ec53500f AW |
152 | return -EFAULT; |
153 | ||
154 | f = fdget(fd); | |
155 | if (!f.file) | |
156 | return -EBADF; | |
157 | ||
158 | vfio_group = kvm_vfio_group_get_external_user(f.file); | |
159 | fdput(f); | |
160 | ||
161 | if (IS_ERR(vfio_group)) | |
162 | return PTR_ERR(vfio_group); | |
163 | ||
164 | ret = -ENOENT; | |
165 | ||
166 | mutex_lock(&kv->lock); | |
167 | ||
168 | list_for_each_entry(kvg, &kv->group_list, node) { | |
169 | if (kvg->vfio_group != vfio_group) | |
170 | continue; | |
171 | ||
172 | list_del(&kvg->node); | |
173 | kvm_vfio_group_put_external_user(kvg->vfio_group); | |
174 | kfree(kvg); | |
175 | ret = 0; | |
176 | break; | |
177 | } | |
178 | ||
179 | mutex_unlock(&kv->lock); | |
180 | ||
181 | kvm_vfio_group_put_external_user(vfio_group); | |
182 | ||
e0f0bbc5 AW |
183 | kvm_vfio_update_coherency(dev); |
184 | ||
ec53500f AW |
185 | return ret; |
186 | } | |
187 | ||
188 | return -ENXIO; | |
189 | } | |
190 | ||
191 | static int kvm_vfio_set_attr(struct kvm_device *dev, | |
192 | struct kvm_device_attr *attr) | |
193 | { | |
194 | switch (attr->group) { | |
195 | case KVM_DEV_VFIO_GROUP: | |
196 | return kvm_vfio_set_group(dev, attr->attr, attr->addr); | |
197 | } | |
198 | ||
199 | return -ENXIO; | |
200 | } | |
201 | ||
202 | static int kvm_vfio_has_attr(struct kvm_device *dev, | |
203 | struct kvm_device_attr *attr) | |
204 | { | |
205 | switch (attr->group) { | |
206 | case KVM_DEV_VFIO_GROUP: | |
207 | switch (attr->attr) { | |
208 | case KVM_DEV_VFIO_GROUP_ADD: | |
209 | case KVM_DEV_VFIO_GROUP_DEL: | |
210 | return 0; | |
211 | } | |
212 | ||
213 | break; | |
214 | } | |
215 | ||
216 | return -ENXIO; | |
217 | } | |
218 | ||
219 | static void kvm_vfio_destroy(struct kvm_device *dev) | |
220 | { | |
221 | struct kvm_vfio *kv = dev->private; | |
222 | struct kvm_vfio_group *kvg, *tmp; | |
223 | ||
224 | list_for_each_entry_safe(kvg, tmp, &kv->group_list, node) { | |
225 | kvm_vfio_group_put_external_user(kvg->vfio_group); | |
226 | list_del(&kvg->node); | |
227 | kfree(kvg); | |
228 | } | |
229 | ||
e0f0bbc5 AW |
230 | kvm_vfio_update_coherency(dev); |
231 | ||
ec53500f AW |
232 | kfree(kv); |
233 | kfree(dev); /* alloc by kvm_ioctl_create_device, free by .destroy */ | |
234 | } | |
235 | ||
236 | static int kvm_vfio_create(struct kvm_device *dev, u32 type) | |
237 | { | |
238 | struct kvm_device *tmp; | |
239 | struct kvm_vfio *kv; | |
240 | ||
241 | /* Only one VFIO "device" per VM */ | |
242 | list_for_each_entry(tmp, &dev->kvm->devices, vm_node) | |
243 | if (tmp->ops == &kvm_vfio_ops) | |
244 | return -EBUSY; | |
245 | ||
246 | kv = kzalloc(sizeof(*kv), GFP_KERNEL); | |
247 | if (!kv) | |
248 | return -ENOMEM; | |
249 | ||
250 | INIT_LIST_HEAD(&kv->group_list); | |
251 | mutex_init(&kv->lock); | |
252 | ||
253 | dev->private = kv; | |
254 | ||
255 | return 0; | |
256 | } | |
257 | ||
258 | struct kvm_device_ops kvm_vfio_ops = { | |
259 | .name = "kvm-vfio", | |
260 | .create = kvm_vfio_create, | |
261 | .destroy = kvm_vfio_destroy, | |
262 | .set_attr = kvm_vfio_set_attr, | |
263 | .has_attr = kvm_vfio_has_attr, | |
264 | }; |