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>
23 struct kvm_vfio_group {
24 struct list_head node;
25 struct vfio_group *vfio_group;
29 struct list_head group_list;
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);
41 return ERR_PTR(-EINVAL);
43 vfio_group = fn(filep);
45 symbol_put(vfio_group_get_external_user);
50 static bool kvm_vfio_external_group_match_file(struct vfio_group *group,
53 bool ret, (*fn)(struct vfio_group *, struct file *);
55 fn = symbol_get(vfio_external_group_match_file);
59 ret = fn(group, filep);
61 symbol_put(vfio_external_group_match_file);
66 static void kvm_vfio_group_put_external_user(struct vfio_group *vfio_group)
68 void (*fn)(struct vfio_group *);
70 fn = symbol_get(vfio_group_put_external_user);
76 symbol_put(vfio_group_put_external_user);
79 static bool kvm_vfio_group_is_coherent(struct vfio_group *vfio_group)
81 long (*fn)(struct vfio_group *, unsigned long);
84 fn = symbol_get(vfio_external_check_extension);
88 ret = fn(vfio_group, VFIO_DMA_CC_IOMMU);
90 symbol_put(vfio_external_check_extension);
96 * Groups can use the same or different IOMMU domains. If the same then
97 * adding a new group may change the coherency of groups we've previously
98 * been told about. We don't want to care about any of that so we retest
99 * each group and bail as soon as we find one that's noncoherent. This
100 * means we only ever [un]register_noncoherent_dma once for the whole device.
102 static void kvm_vfio_update_coherency(struct kvm_device *dev)
104 struct kvm_vfio *kv = dev->private;
105 bool noncoherent = false;
106 struct kvm_vfio_group *kvg;
108 mutex_lock(&kv->lock);
110 list_for_each_entry(kvg, &kv->group_list, node) {
111 if (!kvm_vfio_group_is_coherent(kvg->vfio_group)) {
117 if (noncoherent != kv->noncoherent) {
118 kv->noncoherent = noncoherent;
121 kvm_arch_register_noncoherent_dma(dev->kvm);
123 kvm_arch_unregister_noncoherent_dma(dev->kvm);
126 mutex_unlock(&kv->lock);
129 static int kvm_vfio_set_group(struct kvm_device *dev, long attr, u64 arg)
131 struct kvm_vfio *kv = dev->private;
132 struct vfio_group *vfio_group;
133 struct kvm_vfio_group *kvg;
134 int32_t __user *argp = (int32_t __user *)(unsigned long)arg;
140 case KVM_DEV_VFIO_GROUP_ADD:
141 if (get_user(fd, argp))
148 vfio_group = kvm_vfio_group_get_external_user(f.file);
151 if (IS_ERR(vfio_group))
152 return PTR_ERR(vfio_group);
154 mutex_lock(&kv->lock);
156 list_for_each_entry(kvg, &kv->group_list, node) {
157 if (kvg->vfio_group == vfio_group) {
158 mutex_unlock(&kv->lock);
159 kvm_vfio_group_put_external_user(vfio_group);
164 kvg = kzalloc(sizeof(*kvg), GFP_KERNEL);
166 mutex_unlock(&kv->lock);
167 kvm_vfio_group_put_external_user(vfio_group);
171 list_add_tail(&kvg->node, &kv->group_list);
172 kvg->vfio_group = vfio_group;
174 kvm_arch_start_assignment(dev->kvm);
176 mutex_unlock(&kv->lock);
178 kvm_vfio_update_coherency(dev);
182 case KVM_DEV_VFIO_GROUP_DEL:
183 if (get_user(fd, argp))
192 mutex_lock(&kv->lock);
194 list_for_each_entry(kvg, &kv->group_list, node) {
195 if (!kvm_vfio_external_group_match_file(kvg->vfio_group,
199 list_del(&kvg->node);
200 kvm_vfio_group_put_external_user(kvg->vfio_group);
206 kvm_arch_end_assignment(dev->kvm);
208 mutex_unlock(&kv->lock);
212 kvm_vfio_update_coherency(dev);
220 static int kvm_vfio_set_attr(struct kvm_device *dev,
221 struct kvm_device_attr *attr)
223 switch (attr->group) {
224 case KVM_DEV_VFIO_GROUP:
225 return kvm_vfio_set_group(dev, attr->attr, attr->addr);
231 static int kvm_vfio_has_attr(struct kvm_device *dev,
232 struct kvm_device_attr *attr)
234 switch (attr->group) {
235 case KVM_DEV_VFIO_GROUP:
236 switch (attr->attr) {
237 case KVM_DEV_VFIO_GROUP_ADD:
238 case KVM_DEV_VFIO_GROUP_DEL:
248 static void kvm_vfio_destroy(struct kvm_device *dev)
250 struct kvm_vfio *kv = dev->private;
251 struct kvm_vfio_group *kvg, *tmp;
253 list_for_each_entry_safe(kvg, tmp, &kv->group_list, node) {
254 kvm_vfio_group_put_external_user(kvg->vfio_group);
255 list_del(&kvg->node);
257 kvm_arch_end_assignment(dev->kvm);
260 kvm_vfio_update_coherency(dev);
263 kfree(dev); /* alloc by kvm_ioctl_create_device, free by .destroy */
266 static int kvm_vfio_create(struct kvm_device *dev, u32 type);
268 static struct kvm_device_ops kvm_vfio_ops = {
270 .create = kvm_vfio_create,
271 .destroy = kvm_vfio_destroy,
272 .set_attr = kvm_vfio_set_attr,
273 .has_attr = kvm_vfio_has_attr,
276 static int kvm_vfio_create(struct kvm_device *dev, u32 type)
278 struct kvm_device *tmp;
281 /* Only one VFIO "device" per VM */
282 list_for_each_entry(tmp, &dev->kvm->devices, vm_node)
283 if (tmp->ops == &kvm_vfio_ops)
286 kv = kzalloc(sizeof(*kv), GFP_KERNEL);
290 INIT_LIST_HEAD(&kv->group_list);
291 mutex_init(&kv->lock);
298 int kvm_vfio_ops_init(void)
300 return kvm_register_device_ops(&kvm_vfio_ops, KVM_DEV_TYPE_VFIO);
303 void kvm_vfio_ops_exit(void)
305 kvm_unregister_device_ops(KVM_DEV_TYPE_VFIO);