blob: 281e7cf2b8e56c07ab2e53a21707f3a4cf0c4c60 [file] [log] [blame]
Alex Williamsonec535002013-10-30 11:02:17 -06001/*
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>
Paolo Bonzini3c3c29f2014-09-24 13:02:46 +020021#include "vfio.h"
Alex Williamsonec535002013-10-30 11:02:17 -060022
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;
Alex Williamsone0f0bbc2013-10-30 11:02:30 -060031 bool noncoherent;
Alex Williamsonec535002013-10-30 11:02:17 -060032};
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
Alex Williamson9d830d42014-02-26 11:38:40 -070063static 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
Alex Williamsone0f0bbc2013-10-30 11:02:30 -060079/*
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) {
Alex Williamson9d830d42014-02-26 11:38:40 -070095 if (!kvm_vfio_group_is_coherent(kvg->vfio_group)) {
96 noncoherent = true;
97 break;
98 }
Alex Williamsone0f0bbc2013-10-30 11:02:30 -060099 }
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
Alex Williamsonec535002013-10-30 11:02:17 -0600113static 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;
Paul Bollee81d1ad2014-01-10 01:28:46 +0100118 int32_t __user *argp = (int32_t __user *)(unsigned long)arg;
Alex Williamsonec535002013-10-30 11:02:17 -0600119 struct fd f;
120 int32_t fd;
121 int ret;
122
123 switch (attr) {
124 case KVM_DEV_VFIO_GROUP_ADD:
Paul Bollee81d1ad2014-01-10 01:28:46 +0100125 if (get_user(fd, argp))
Alex Williamsonec535002013-10-30 11:02:17 -0600126 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
Alex Williamsone0f0bbc2013-10-30 11:02:30 -0600160 kvm_vfio_update_coherency(dev);
161
Alex Williamsonec535002013-10-30 11:02:17 -0600162 return 0;
163
164 case KVM_DEV_VFIO_GROUP_DEL:
Paul Bollee81d1ad2014-01-10 01:28:46 +0100165 if (get_user(fd, argp))
Alex Williamsonec535002013-10-30 11:02:17 -0600166 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
Alex Williamsone0f0bbc2013-10-30 11:02:30 -0600197 kvm_vfio_update_coherency(dev);
198
Alex Williamsonec535002013-10-30 11:02:17 -0600199 return ret;
200 }
201
202 return -ENXIO;
203}
204
205static 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
216static 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
233static 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
Alex Williamsone0f0bbc2013-10-30 11:02:30 -0600244 kvm_vfio_update_coherency(dev);
245
Alex Williamsonec535002013-10-30 11:02:17 -0600246 kfree(kv);
247 kfree(dev); /* alloc by kvm_ioctl_create_device, free by .destroy */
248}
249
Will Deacon80ce1632014-09-02 10:27:36 +0100250static int kvm_vfio_create(struct kvm_device *dev, u32 type);
251
252static 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
Alex Williamsonec535002013-10-30 11:02:17 -0600260static 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
Paolo Bonzini3c3c29f2014-09-24 13:02:46 +0200282int kvm_vfio_ops_init(void)
Will Deacon80ce1632014-09-02 10:27:36 +0100283{
284 return kvm_register_device_ops(&kvm_vfio_ops, KVM_DEV_TYPE_VFIO);
285}