Loading...
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * VFIO-KVM bridge pseudo device
4 *
5 * Copyright (C) 2013 Red Hat, Inc. All rights reserved.
6 * Author: Alex Williamson <alex.williamson@redhat.com>
7 */
8
9#include <linux/errno.h>
10#include <linux/file.h>
11#include <linux/kvm_host.h>
12#include <linux/list.h>
13#include <linux/module.h>
14#include <linux/mutex.h>
15#include <linux/slab.h>
16#include <linux/uaccess.h>
17#include <linux/vfio.h>
18#include "vfio.h"
19
20#ifdef CONFIG_SPAPR_TCE_IOMMU
21#include <asm/kvm_ppc.h>
22#endif
23
24struct kvm_vfio_group {
25 struct list_head node;
26 struct file *file;
27#ifdef CONFIG_SPAPR_TCE_IOMMU
28 struct iommu_group *iommu_group;
29#endif
30};
31
32struct kvm_vfio {
33 struct list_head group_list;
34 struct mutex lock;
35 bool noncoherent;
36};
37
38static void kvm_vfio_file_set_kvm(struct file *file, struct kvm *kvm)
39{
40 void (*fn)(struct file *file, struct kvm *kvm);
41
42 fn = symbol_get(vfio_file_set_kvm);
43 if (!fn)
44 return;
45
46 fn(file, kvm);
47
48 symbol_put(vfio_file_set_kvm);
49}
50
51static bool kvm_vfio_file_enforced_coherent(struct file *file)
52{
53 bool (*fn)(struct file *file);
54 bool ret;
55
56 fn = symbol_get(vfio_file_enforced_coherent);
57 if (!fn)
58 return false;
59
60 ret = fn(file);
61
62 symbol_put(vfio_file_enforced_coherent);
63
64 return ret;
65}
66
67static bool kvm_vfio_file_is_group(struct file *file)
68{
69 bool (*fn)(struct file *file);
70 bool ret;
71
72 fn = symbol_get(vfio_file_is_group);
73 if (!fn)
74 return false;
75
76 ret = fn(file);
77
78 symbol_put(vfio_file_is_group);
79
80 return ret;
81}
82
83#ifdef CONFIG_SPAPR_TCE_IOMMU
84static struct iommu_group *kvm_vfio_file_iommu_group(struct file *file)
85{
86 struct iommu_group *(*fn)(struct file *file);
87 struct iommu_group *ret;
88
89 fn = symbol_get(vfio_file_iommu_group);
90 if (!fn)
91 return NULL;
92
93 ret = fn(file);
94
95 symbol_put(vfio_file_iommu_group);
96
97 return ret;
98}
99
100static void kvm_spapr_tce_release_vfio_group(struct kvm *kvm,
101 struct kvm_vfio_group *kvg)
102{
103 if (WARN_ON_ONCE(!kvg->iommu_group))
104 return;
105
106 kvm_spapr_tce_release_iommu_group(kvm, kvg->iommu_group);
107 iommu_group_put(kvg->iommu_group);
108 kvg->iommu_group = NULL;
109}
110#endif
111
112/*
113 * Groups can use the same or different IOMMU domains. If the same then
114 * adding a new group may change the coherency of groups we've previously
115 * been told about. We don't want to care about any of that so we retest
116 * each group and bail as soon as we find one that's noncoherent. This
117 * means we only ever [un]register_noncoherent_dma once for the whole device.
118 */
119static void kvm_vfio_update_coherency(struct kvm_device *dev)
120{
121 struct kvm_vfio *kv = dev->private;
122 bool noncoherent = false;
123 struct kvm_vfio_group *kvg;
124
125 mutex_lock(&kv->lock);
126
127 list_for_each_entry(kvg, &kv->group_list, node) {
128 if (!kvm_vfio_file_enforced_coherent(kvg->file)) {
129 noncoherent = true;
130 break;
131 }
132 }
133
134 if (noncoherent != kv->noncoherent) {
135 kv->noncoherent = noncoherent;
136
137 if (kv->noncoherent)
138 kvm_arch_register_noncoherent_dma(dev->kvm);
139 else
140 kvm_arch_unregister_noncoherent_dma(dev->kvm);
141 }
142
143 mutex_unlock(&kv->lock);
144}
145
146static int kvm_vfio_group_add(struct kvm_device *dev, unsigned int fd)
147{
148 struct kvm_vfio *kv = dev->private;
149 struct kvm_vfio_group *kvg;
150 struct file *filp;
151 int ret;
152
153 filp = fget(fd);
154 if (!filp)
155 return -EBADF;
156
157 /* Ensure the FD is a vfio group FD.*/
158 if (!kvm_vfio_file_is_group(filp)) {
159 ret = -EINVAL;
160 goto err_fput;
161 }
162
163 mutex_lock(&kv->lock);
164
165 list_for_each_entry(kvg, &kv->group_list, node) {
166 if (kvg->file == filp) {
167 ret = -EEXIST;
168 goto err_unlock;
169 }
170 }
171
172 kvg = kzalloc(sizeof(*kvg), GFP_KERNEL_ACCOUNT);
173 if (!kvg) {
174 ret = -ENOMEM;
175 goto err_unlock;
176 }
177
178 kvg->file = filp;
179 list_add_tail(&kvg->node, &kv->group_list);
180
181 kvm_arch_start_assignment(dev->kvm);
182
183 mutex_unlock(&kv->lock);
184
185 kvm_vfio_file_set_kvm(kvg->file, dev->kvm);
186 kvm_vfio_update_coherency(dev);
187
188 return 0;
189err_unlock:
190 mutex_unlock(&kv->lock);
191err_fput:
192 fput(filp);
193 return ret;
194}
195
196static int kvm_vfio_group_del(struct kvm_device *dev, unsigned int fd)
197{
198 struct kvm_vfio *kv = dev->private;
199 struct kvm_vfio_group *kvg;
200 struct fd f;
201 int ret;
202
203 f = fdget(fd);
204 if (!f.file)
205 return -EBADF;
206
207 ret = -ENOENT;
208
209 mutex_lock(&kv->lock);
210
211 list_for_each_entry(kvg, &kv->group_list, node) {
212 if (kvg->file != f.file)
213 continue;
214
215 list_del(&kvg->node);
216 kvm_arch_end_assignment(dev->kvm);
217#ifdef CONFIG_SPAPR_TCE_IOMMU
218 kvm_spapr_tce_release_vfio_group(dev->kvm, kvg);
219#endif
220 kvm_vfio_file_set_kvm(kvg->file, NULL);
221 fput(kvg->file);
222 kfree(kvg);
223 ret = 0;
224 break;
225 }
226
227 mutex_unlock(&kv->lock);
228
229 fdput(f);
230
231 kvm_vfio_update_coherency(dev);
232
233 return ret;
234}
235
236#ifdef CONFIG_SPAPR_TCE_IOMMU
237static int kvm_vfio_group_set_spapr_tce(struct kvm_device *dev,
238 void __user *arg)
239{
240 struct kvm_vfio_spapr_tce param;
241 struct kvm_vfio *kv = dev->private;
242 struct kvm_vfio_group *kvg;
243 struct fd f;
244 int ret;
245
246 if (copy_from_user(¶m, arg, sizeof(struct kvm_vfio_spapr_tce)))
247 return -EFAULT;
248
249 f = fdget(param.groupfd);
250 if (!f.file)
251 return -EBADF;
252
253 ret = -ENOENT;
254
255 mutex_lock(&kv->lock);
256
257 list_for_each_entry(kvg, &kv->group_list, node) {
258 if (kvg->file != f.file)
259 continue;
260
261 if (!kvg->iommu_group) {
262 kvg->iommu_group = kvm_vfio_file_iommu_group(kvg->file);
263 if (WARN_ON_ONCE(!kvg->iommu_group)) {
264 ret = -EIO;
265 goto err_fdput;
266 }
267 }
268
269 ret = kvm_spapr_tce_attach_iommu_group(dev->kvm, param.tablefd,
270 kvg->iommu_group);
271 break;
272 }
273
274err_fdput:
275 mutex_unlock(&kv->lock);
276 fdput(f);
277 return ret;
278}
279#endif
280
281static int kvm_vfio_set_group(struct kvm_device *dev, long attr,
282 void __user *arg)
283{
284 int32_t __user *argp = arg;
285 int32_t fd;
286
287 switch (attr) {
288 case KVM_DEV_VFIO_GROUP_ADD:
289 if (get_user(fd, argp))
290 return -EFAULT;
291 return kvm_vfio_group_add(dev, fd);
292
293 case KVM_DEV_VFIO_GROUP_DEL:
294 if (get_user(fd, argp))
295 return -EFAULT;
296 return kvm_vfio_group_del(dev, fd);
297
298#ifdef CONFIG_SPAPR_TCE_IOMMU
299 case KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE:
300 return kvm_vfio_group_set_spapr_tce(dev, arg);
301#endif
302 }
303
304 return -ENXIO;
305}
306
307static int kvm_vfio_set_attr(struct kvm_device *dev,
308 struct kvm_device_attr *attr)
309{
310 switch (attr->group) {
311 case KVM_DEV_VFIO_GROUP:
312 return kvm_vfio_set_group(dev, attr->attr,
313 u64_to_user_ptr(attr->addr));
314 }
315
316 return -ENXIO;
317}
318
319static int kvm_vfio_has_attr(struct kvm_device *dev,
320 struct kvm_device_attr *attr)
321{
322 switch (attr->group) {
323 case KVM_DEV_VFIO_GROUP:
324 switch (attr->attr) {
325 case KVM_DEV_VFIO_GROUP_ADD:
326 case KVM_DEV_VFIO_GROUP_DEL:
327#ifdef CONFIG_SPAPR_TCE_IOMMU
328 case KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE:
329#endif
330 return 0;
331 }
332
333 break;
334 }
335
336 return -ENXIO;
337}
338
339static void kvm_vfio_release(struct kvm_device *dev)
340{
341 struct kvm_vfio *kv = dev->private;
342 struct kvm_vfio_group *kvg, *tmp;
343
344 list_for_each_entry_safe(kvg, tmp, &kv->group_list, node) {
345#ifdef CONFIG_SPAPR_TCE_IOMMU
346 kvm_spapr_tce_release_vfio_group(dev->kvm, kvg);
347#endif
348 kvm_vfio_file_set_kvm(kvg->file, NULL);
349 fput(kvg->file);
350 list_del(&kvg->node);
351 kfree(kvg);
352 kvm_arch_end_assignment(dev->kvm);
353 }
354
355 kvm_vfio_update_coherency(dev);
356
357 kfree(kv);
358 kfree(dev); /* alloc by kvm_ioctl_create_device, free by .release */
359}
360
361static int kvm_vfio_create(struct kvm_device *dev, u32 type);
362
363static struct kvm_device_ops kvm_vfio_ops = {
364 .name = "kvm-vfio",
365 .create = kvm_vfio_create,
366 .release = kvm_vfio_release,
367 .set_attr = kvm_vfio_set_attr,
368 .has_attr = kvm_vfio_has_attr,
369};
370
371static int kvm_vfio_create(struct kvm_device *dev, u32 type)
372{
373 struct kvm_device *tmp;
374 struct kvm_vfio *kv;
375
376 /* Only one VFIO "device" per VM */
377 list_for_each_entry(tmp, &dev->kvm->devices, vm_node)
378 if (tmp->ops == &kvm_vfio_ops)
379 return -EBUSY;
380
381 kv = kzalloc(sizeof(*kv), GFP_KERNEL_ACCOUNT);
382 if (!kv)
383 return -ENOMEM;
384
385 INIT_LIST_HEAD(&kv->group_list);
386 mutex_init(&kv->lock);
387
388 dev->private = kv;
389
390 return 0;
391}
392
393int kvm_vfio_ops_init(void)
394{
395 return kvm_register_device_ops(&kvm_vfio_ops, KVM_DEV_TYPE_VFIO);
396}
397
398void kvm_vfio_ops_exit(void)
399{
400 kvm_unregister_device_ops(KVM_DEV_TYPE_VFIO);
401}
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 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
76static 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
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 */
99static 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) {
108 if (!kvm_vfio_group_is_coherent(kvg->vfio_group)) {
109 noncoherent = true;
110 break;
111 }
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
126static 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;
131 int32_t __user *argp = (int32_t __user *)(unsigned long)arg;
132 struct fd f;
133 int32_t fd;
134 int ret;
135
136 switch (attr) {
137 case KVM_DEV_VFIO_GROUP_ADD:
138 if (get_user(fd, argp))
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
171 kvm_arch_start_assignment(dev->kvm);
172
173 mutex_unlock(&kv->lock);
174
175 kvm_vfio_group_set_kvm(vfio_group, dev->kvm);
176
177 kvm_vfio_update_coherency(dev);
178
179 return 0;
180
181 case KVM_DEV_VFIO_GROUP_DEL:
182 if (get_user(fd, argp))
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
210 kvm_arch_end_assignment(dev->kvm);
211
212 mutex_unlock(&kv->lock);
213
214 kvm_vfio_group_set_kvm(vfio_group, NULL);
215
216 kvm_vfio_group_put_external_user(vfio_group);
217
218 kvm_vfio_update_coherency(dev);
219
220 return ret;
221 }
222
223 return -ENXIO;
224}
225
226static 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
237static 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
254static 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) {
260 kvm_vfio_group_set_kvm(kvg->vfio_group, NULL);
261 kvm_vfio_group_put_external_user(kvg->vfio_group);
262 list_del(&kvg->node);
263 kfree(kvg);
264 kvm_arch_end_assignment(dev->kvm);
265 }
266
267 kvm_vfio_update_coherency(dev);
268
269 kfree(kv);
270 kfree(dev); /* alloc by kvm_ioctl_create_device, free by .destroy */
271}
272
273static int kvm_vfio_create(struct kvm_device *dev, u32 type);
274
275static 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
283static 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
305int kvm_vfio_ops_init(void)
306{
307 return kvm_register_device_ops(&kvm_vfio_ops, KVM_DEV_TYPE_VFIO);
308}
309
310void kvm_vfio_ops_exit(void)
311{
312 kvm_unregister_device_ops(KVM_DEV_TYPE_VFIO);
313}