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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
23#ifdef CONFIG_SPAPR_TCE_IOMMU
24#include <asm/kvm_ppc.h>
25#endif
26
27struct kvm_vfio_group {
28 struct list_head node;
29 struct vfio_group *vfio_group;
30};
31
32struct kvm_vfio {
33 struct list_head group_list;
34 struct mutex lock;
35 bool noncoherent;
36};
37
38static struct vfio_group *kvm_vfio_group_get_external_user(struct file *filep)
39{
40 struct vfio_group *vfio_group;
41 struct vfio_group *(*fn)(struct file *);
42
43 fn = symbol_get(vfio_group_get_external_user);
44 if (!fn)
45 return ERR_PTR(-EINVAL);
46
47 vfio_group = fn(filep);
48
49 symbol_put(vfio_group_get_external_user);
50
51 return vfio_group;
52}
53
54static bool kvm_vfio_external_group_match_file(struct vfio_group *group,
55 struct file *filep)
56{
57 bool ret, (*fn)(struct vfio_group *, struct file *);
58
59 fn = symbol_get(vfio_external_group_match_file);
60 if (!fn)
61 return false;
62
63 ret = fn(group, filep);
64
65 symbol_put(vfio_external_group_match_file);
66
67 return ret;
68}
69
70static void kvm_vfio_group_put_external_user(struct vfio_group *vfio_group)
71{
72 void (*fn)(struct vfio_group *);
73
74 fn = symbol_get(vfio_group_put_external_user);
75 if (!fn)
76 return;
77
78 fn(vfio_group);
79
80 symbol_put(vfio_group_put_external_user);
81}
82
83static void kvm_vfio_group_set_kvm(struct vfio_group *group, struct kvm *kvm)
84{
85 void (*fn)(struct vfio_group *, struct kvm *);
86
87 fn = symbol_get(vfio_group_set_kvm);
88 if (!fn)
89 return;
90
91 fn(group, kvm);
92
93 symbol_put(vfio_group_set_kvm);
94}
95
96static bool kvm_vfio_group_is_coherent(struct vfio_group *vfio_group)
97{
98 long (*fn)(struct vfio_group *, unsigned long);
99 long ret;
100
101 fn = symbol_get(vfio_external_check_extension);
102 if (!fn)
103 return false;
104
105 ret = fn(vfio_group, VFIO_DMA_CC_IOMMU);
106
107 symbol_put(vfio_external_check_extension);
108
109 return ret > 0;
110}
111
112#ifdef CONFIG_SPAPR_TCE_IOMMU
113static int kvm_vfio_external_user_iommu_id(struct vfio_group *vfio_group)
114{
115 int (*fn)(struct vfio_group *);
116 int ret = -EINVAL;
117
118 fn = symbol_get(vfio_external_user_iommu_id);
119 if (!fn)
120 return ret;
121
122 ret = fn(vfio_group);
123
124 symbol_put(vfio_external_user_iommu_id);
125
126 return ret;
127}
128
129static struct iommu_group *kvm_vfio_group_get_iommu_group(
130 struct vfio_group *group)
131{
132 int group_id = kvm_vfio_external_user_iommu_id(group);
133
134 if (group_id < 0)
135 return NULL;
136
137 return iommu_group_get_by_id(group_id);
138}
139
140static void kvm_spapr_tce_release_vfio_group(struct kvm *kvm,
141 struct vfio_group *vfio_group)
142{
143 struct iommu_group *grp = kvm_vfio_group_get_iommu_group(vfio_group);
144
145 if (WARN_ON_ONCE(!grp))
146 return;
147
148 kvm_spapr_tce_release_iommu_group(kvm, grp);
149 iommu_group_put(grp);
150}
151#endif
152
153/*
154 * Groups can use the same or different IOMMU domains. If the same then
155 * adding a new group may change the coherency of groups we've previously
156 * been told about. We don't want to care about any of that so we retest
157 * each group and bail as soon as we find one that's noncoherent. This
158 * means we only ever [un]register_noncoherent_dma once for the whole device.
159 */
160static void kvm_vfio_update_coherency(struct kvm_device *dev)
161{
162 struct kvm_vfio *kv = dev->private;
163 bool noncoherent = false;
164 struct kvm_vfio_group *kvg;
165
166 mutex_lock(&kv->lock);
167
168 list_for_each_entry(kvg, &kv->group_list, node) {
169 if (!kvm_vfio_group_is_coherent(kvg->vfio_group)) {
170 noncoherent = true;
171 break;
172 }
173 }
174
175 if (noncoherent != kv->noncoherent) {
176 kv->noncoherent = noncoherent;
177
178 if (kv->noncoherent)
179 kvm_arch_register_noncoherent_dma(dev->kvm);
180 else
181 kvm_arch_unregister_noncoherent_dma(dev->kvm);
182 }
183
184 mutex_unlock(&kv->lock);
185}
186
187static int kvm_vfio_set_group(struct kvm_device *dev, long attr, u64 arg)
188{
189 struct kvm_vfio *kv = dev->private;
190 struct vfio_group *vfio_group;
191 struct kvm_vfio_group *kvg;
192 int32_t __user *argp = (int32_t __user *)(unsigned long)arg;
193 struct fd f;
194 int32_t fd;
195 int ret;
196
197 switch (attr) {
198 case KVM_DEV_VFIO_GROUP_ADD:
199 if (get_user(fd, argp))
200 return -EFAULT;
201
202 f = fdget(fd);
203 if (!f.file)
204 return -EBADF;
205
206 vfio_group = kvm_vfio_group_get_external_user(f.file);
207 fdput(f);
208
209 if (IS_ERR(vfio_group))
210 return PTR_ERR(vfio_group);
211
212 mutex_lock(&kv->lock);
213
214 list_for_each_entry(kvg, &kv->group_list, node) {
215 if (kvg->vfio_group == vfio_group) {
216 mutex_unlock(&kv->lock);
217 kvm_vfio_group_put_external_user(vfio_group);
218 return -EEXIST;
219 }
220 }
221
222 kvg = kzalloc(sizeof(*kvg), GFP_KERNEL);
223 if (!kvg) {
224 mutex_unlock(&kv->lock);
225 kvm_vfio_group_put_external_user(vfio_group);
226 return -ENOMEM;
227 }
228
229 list_add_tail(&kvg->node, &kv->group_list);
230 kvg->vfio_group = vfio_group;
231
232 kvm_arch_start_assignment(dev->kvm);
233
234 mutex_unlock(&kv->lock);
235
236 kvm_vfio_group_set_kvm(vfio_group, dev->kvm);
237
238 kvm_vfio_update_coherency(dev);
239
240 return 0;
241
242 case KVM_DEV_VFIO_GROUP_DEL:
243 if (get_user(fd, argp))
244 return -EFAULT;
245
246 f = fdget(fd);
247 if (!f.file)
248 return -EBADF;
249
250 ret = -ENOENT;
251
252 mutex_lock(&kv->lock);
253
254 list_for_each_entry(kvg, &kv->group_list, node) {
255 if (!kvm_vfio_external_group_match_file(kvg->vfio_group,
256 f.file))
257 continue;
258
259 list_del(&kvg->node);
260 kvm_arch_end_assignment(dev->kvm);
261#ifdef CONFIG_SPAPR_TCE_IOMMU
262 kvm_spapr_tce_release_vfio_group(dev->kvm,
263 kvg->vfio_group);
264#endif
265 kvm_vfio_group_set_kvm(kvg->vfio_group, NULL);
266 kvm_vfio_group_put_external_user(kvg->vfio_group);
267 kfree(kvg);
268 ret = 0;
269 break;
270 }
271
272 mutex_unlock(&kv->lock);
273
274 fdput(f);
275
276 kvm_vfio_update_coherency(dev);
277
278 return ret;
279
280#ifdef CONFIG_SPAPR_TCE_IOMMU
281 case KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE: {
282 struct kvm_vfio_spapr_tce param;
283 struct kvm_vfio *kv = dev->private;
284 struct vfio_group *vfio_group;
285 struct kvm_vfio_group *kvg;
286 struct fd f;
287 struct iommu_group *grp;
288
289 if (copy_from_user(¶m, (void __user *)arg,
290 sizeof(struct kvm_vfio_spapr_tce)))
291 return -EFAULT;
292
293 f = fdget(param.groupfd);
294 if (!f.file)
295 return -EBADF;
296
297 vfio_group = kvm_vfio_group_get_external_user(f.file);
298 fdput(f);
299
300 if (IS_ERR(vfio_group))
301 return PTR_ERR(vfio_group);
302
303 grp = kvm_vfio_group_get_iommu_group(vfio_group);
304 if (WARN_ON_ONCE(!grp)) {
305 kvm_vfio_group_put_external_user(vfio_group);
306 return -EIO;
307 }
308
309 ret = -ENOENT;
310
311 mutex_lock(&kv->lock);
312
313 list_for_each_entry(kvg, &kv->group_list, node) {
314 if (kvg->vfio_group != vfio_group)
315 continue;
316
317 ret = kvm_spapr_tce_attach_iommu_group(dev->kvm,
318 param.tablefd, grp);
319 break;
320 }
321
322 mutex_unlock(&kv->lock);
323
324 iommu_group_put(grp);
325 kvm_vfio_group_put_external_user(vfio_group);
326
327 return ret;
328 }
329#endif /* CONFIG_SPAPR_TCE_IOMMU */
330 }
331
332 return -ENXIO;
333}
334
335static int kvm_vfio_set_attr(struct kvm_device *dev,
336 struct kvm_device_attr *attr)
337{
338 switch (attr->group) {
339 case KVM_DEV_VFIO_GROUP:
340 return kvm_vfio_set_group(dev, attr->attr, attr->addr);
341 }
342
343 return -ENXIO;
344}
345
346static int kvm_vfio_has_attr(struct kvm_device *dev,
347 struct kvm_device_attr *attr)
348{
349 switch (attr->group) {
350 case KVM_DEV_VFIO_GROUP:
351 switch (attr->attr) {
352 case KVM_DEV_VFIO_GROUP_ADD:
353 case KVM_DEV_VFIO_GROUP_DEL:
354#ifdef CONFIG_SPAPR_TCE_IOMMU
355 case KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE:
356#endif
357 return 0;
358 }
359
360 break;
361 }
362
363 return -ENXIO;
364}
365
366static void kvm_vfio_destroy(struct kvm_device *dev)
367{
368 struct kvm_vfio *kv = dev->private;
369 struct kvm_vfio_group *kvg, *tmp;
370
371 list_for_each_entry_safe(kvg, tmp, &kv->group_list, node) {
372#ifdef CONFIG_SPAPR_TCE_IOMMU
373 kvm_spapr_tce_release_vfio_group(dev->kvm, kvg->vfio_group);
374#endif
375 kvm_vfio_group_set_kvm(kvg->vfio_group, NULL);
376 kvm_vfio_group_put_external_user(kvg->vfio_group);
377 list_del(&kvg->node);
378 kfree(kvg);
379 kvm_arch_end_assignment(dev->kvm);
380 }
381
382 kvm_vfio_update_coherency(dev);
383
384 kfree(kv);
385 kfree(dev); /* alloc by kvm_ioctl_create_device, free by .destroy */
386}
387
388static int kvm_vfio_create(struct kvm_device *dev, u32 type);
389
390static struct kvm_device_ops kvm_vfio_ops = {
391 .name = "kvm-vfio",
392 .create = kvm_vfio_create,
393 .destroy = kvm_vfio_destroy,
394 .set_attr = kvm_vfio_set_attr,
395 .has_attr = kvm_vfio_has_attr,
396};
397
398static int kvm_vfio_create(struct kvm_device *dev, u32 type)
399{
400 struct kvm_device *tmp;
401 struct kvm_vfio *kv;
402
403 /* Only one VFIO "device" per VM */
404 list_for_each_entry(tmp, &dev->kvm->devices, vm_node)
405 if (tmp->ops == &kvm_vfio_ops)
406 return -EBUSY;
407
408 kv = kzalloc(sizeof(*kv), GFP_KERNEL);
409 if (!kv)
410 return -ENOMEM;
411
412 INIT_LIST_HEAD(&kv->group_list);
413 mutex_init(&kv->lock);
414
415 dev->private = kv;
416
417 return 0;
418}
419
420int kvm_vfio_ops_init(void)
421{
422 return kvm_register_device_ops(&kvm_vfio_ops, KVM_DEV_TYPE_VFIO);
423}
424
425void kvm_vfio_ops_exit(void)
426{
427 kvm_unregister_device_ops(KVM_DEV_TYPE_VFIO);
428}