Linux 4.8.3
[linux/fpc-iii.git] / virt / kvm / vfio.c
blob1dd087da6f31ae2f38c70042213ee6e5159cee10
1 /*
2 * VFIO-KVM bridge pseudo device
4 * Copyright (C) 2013 Red Hat, Inc. All rights reserved.
5 * Author: Alex Williamson <alex.williamson@redhat.com>
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.
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"
23 struct kvm_vfio_group {
24 struct list_head node;
25 struct vfio_group *vfio_group;
28 struct kvm_vfio {
29 struct list_head group_list;
30 struct mutex lock;
31 bool noncoherent;
34 static struct vfio_group *kvm_vfio_group_get_external_user(struct file *filep)
36 struct vfio_group *vfio_group;
37 struct vfio_group *(*fn)(struct file *);
39 fn = symbol_get(vfio_group_get_external_user);
40 if (!fn)
41 return ERR_PTR(-EINVAL);
43 vfio_group = fn(filep);
45 symbol_put(vfio_group_get_external_user);
47 return vfio_group;
50 static void kvm_vfio_group_put_external_user(struct vfio_group *vfio_group)
52 void (*fn)(struct vfio_group *);
54 fn = symbol_get(vfio_group_put_external_user);
55 if (!fn)
56 return;
58 fn(vfio_group);
60 symbol_put(vfio_group_put_external_user);
63 static bool kvm_vfio_group_is_coherent(struct vfio_group *vfio_group)
65 long (*fn)(struct vfio_group *, unsigned long);
66 long ret;
68 fn = symbol_get(vfio_external_check_extension);
69 if (!fn)
70 return false;
72 ret = fn(vfio_group, VFIO_DMA_CC_IOMMU);
74 symbol_put(vfio_external_check_extension);
76 return ret > 0;
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.
86 static void kvm_vfio_update_coherency(struct kvm_device *dev)
88 struct kvm_vfio *kv = dev->private;
89 bool noncoherent = false;
90 struct kvm_vfio_group *kvg;
92 mutex_lock(&kv->lock);
94 list_for_each_entry(kvg, &kv->group_list, node) {
95 if (!kvm_vfio_group_is_coherent(kvg->vfio_group)) {
96 noncoherent = true;
97 break;
101 if (noncoherent != kv->noncoherent) {
102 kv->noncoherent = noncoherent;
104 if (kv->noncoherent)
105 kvm_arch_register_noncoherent_dma(dev->kvm);
106 else
107 kvm_arch_unregister_noncoherent_dma(dev->kvm);
110 mutex_unlock(&kv->lock);
113 static int kvm_vfio_set_group(struct kvm_device *dev, long attr, u64 arg)
115 struct kvm_vfio *kv = dev->private;
116 struct vfio_group *vfio_group;
117 struct kvm_vfio_group *kvg;
118 int32_t __user *argp = (int32_t __user *)(unsigned long)arg;
119 struct fd f;
120 int32_t fd;
121 int ret;
123 switch (attr) {
124 case KVM_DEV_VFIO_GROUP_ADD:
125 if (get_user(fd, argp))
126 return -EFAULT;
128 f = fdget(fd);
129 if (!f.file)
130 return -EBADF;
132 vfio_group = kvm_vfio_group_get_external_user(f.file);
133 fdput(f);
135 if (IS_ERR(vfio_group))
136 return PTR_ERR(vfio_group);
138 mutex_lock(&kv->lock);
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;
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;
155 list_add_tail(&kvg->node, &kv->group_list);
156 kvg->vfio_group = vfio_group;
158 kvm_arch_start_assignment(dev->kvm);
160 mutex_unlock(&kv->lock);
162 kvm_vfio_update_coherency(dev);
164 return 0;
166 case KVM_DEV_VFIO_GROUP_DEL:
167 if (get_user(fd, argp))
168 return -EFAULT;
170 f = fdget(fd);
171 if (!f.file)
172 return -EBADF;
174 vfio_group = kvm_vfio_group_get_external_user(f.file);
175 fdput(f);
177 if (IS_ERR(vfio_group))
178 return PTR_ERR(vfio_group);
180 ret = -ENOENT;
182 mutex_lock(&kv->lock);
184 list_for_each_entry(kvg, &kv->group_list, node) {
185 if (kvg->vfio_group != vfio_group)
186 continue;
188 list_del(&kvg->node);
189 kvm_vfio_group_put_external_user(kvg->vfio_group);
190 kfree(kvg);
191 ret = 0;
192 break;
195 kvm_arch_end_assignment(dev->kvm);
197 mutex_unlock(&kv->lock);
199 kvm_vfio_group_put_external_user(vfio_group);
201 kvm_vfio_update_coherency(dev);
203 return ret;
206 return -ENXIO;
209 static int kvm_vfio_set_attr(struct kvm_device *dev,
210 struct kvm_device_attr *attr)
212 switch (attr->group) {
213 case KVM_DEV_VFIO_GROUP:
214 return kvm_vfio_set_group(dev, attr->attr, attr->addr);
217 return -ENXIO;
220 static int kvm_vfio_has_attr(struct kvm_device *dev,
221 struct kvm_device_attr *attr)
223 switch (attr->group) {
224 case KVM_DEV_VFIO_GROUP:
225 switch (attr->attr) {
226 case KVM_DEV_VFIO_GROUP_ADD:
227 case KVM_DEV_VFIO_GROUP_DEL:
228 return 0;
231 break;
234 return -ENXIO;
237 static void kvm_vfio_destroy(struct kvm_device *dev)
239 struct kvm_vfio *kv = dev->private;
240 struct kvm_vfio_group *kvg, *tmp;
242 list_for_each_entry_safe(kvg, tmp, &kv->group_list, node) {
243 kvm_vfio_group_put_external_user(kvg->vfio_group);
244 list_del(&kvg->node);
245 kfree(kvg);
246 kvm_arch_end_assignment(dev->kvm);
249 kvm_vfio_update_coherency(dev);
251 kfree(kv);
252 kfree(dev); /* alloc by kvm_ioctl_create_device, free by .destroy */
255 static int kvm_vfio_create(struct kvm_device *dev, u32 type);
257 static struct kvm_device_ops kvm_vfio_ops = {
258 .name = "kvm-vfio",
259 .create = kvm_vfio_create,
260 .destroy = kvm_vfio_destroy,
261 .set_attr = kvm_vfio_set_attr,
262 .has_attr = kvm_vfio_has_attr,
265 static int kvm_vfio_create(struct kvm_device *dev, u32 type)
267 struct kvm_device *tmp;
268 struct kvm_vfio *kv;
270 /* Only one VFIO "device" per VM */
271 list_for_each_entry(tmp, &dev->kvm->devices, vm_node)
272 if (tmp->ops == &kvm_vfio_ops)
273 return -EBUSY;
275 kv = kzalloc(sizeof(*kv), GFP_KERNEL);
276 if (!kv)
277 return -ENOMEM;
279 INIT_LIST_HEAD(&kv->group_list);
280 mutex_init(&kv->lock);
282 dev->private = kv;
284 return 0;
287 int kvm_vfio_ops_init(void)
289 return kvm_register_device_ops(&kvm_vfio_ops, KVM_DEV_TYPE_VFIO);
292 void kvm_vfio_ops_exit(void)
294 kvm_unregister_device_ops(KVM_DEV_TYPE_VFIO);