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>
22 struct kvm_vfio_group {
23 struct list_head node;
24 struct vfio_group *vfio_group;
28 struct list_head group_list;
32 static struct vfio_group *kvm_vfio_group_get_external_user(struct file *filep)
34 struct vfio_group *vfio_group;
35 struct vfio_group *(*fn)(struct file *);
37 fn = symbol_get(vfio_group_get_external_user);
39 return ERR_PTR(-EINVAL);
41 vfio_group = fn(filep);
43 symbol_put(vfio_group_get_external_user);
48 static void kvm_vfio_group_put_external_user(struct vfio_group *vfio_group)
50 void (*fn)(struct vfio_group *);
52 fn = symbol_get(vfio_group_put_external_user);
58 symbol_put(vfio_group_put_external_user);
61 static int kvm_vfio_set_group(struct kvm_device *dev, long attr, u64 arg)
63 struct kvm_vfio *kv = dev->private;
64 struct vfio_group *vfio_group;
65 struct kvm_vfio_group *kvg;
66 void __user *argp = (void __user *)arg;
72 case KVM_DEV_VFIO_GROUP_ADD:
73 if (get_user(fd, (int32_t __user *)argp))
80 vfio_group = kvm_vfio_group_get_external_user(f.file);
83 if (IS_ERR(vfio_group))
84 return PTR_ERR(vfio_group);
86 mutex_lock(&kv->lock);
88 list_for_each_entry(kvg, &kv->group_list, node) {
89 if (kvg->vfio_group == vfio_group) {
90 mutex_unlock(&kv->lock);
91 kvm_vfio_group_put_external_user(vfio_group);
96 kvg = kzalloc(sizeof(*kvg), GFP_KERNEL);
98 mutex_unlock(&kv->lock);
99 kvm_vfio_group_put_external_user(vfio_group);
103 list_add_tail(&kvg->node, &kv->group_list);
104 kvg->vfio_group = vfio_group;
106 mutex_unlock(&kv->lock);
110 case KVM_DEV_VFIO_GROUP_DEL:
111 if (get_user(fd, (int32_t __user *)argp))
118 vfio_group = kvm_vfio_group_get_external_user(f.file);
121 if (IS_ERR(vfio_group))
122 return PTR_ERR(vfio_group);
126 mutex_lock(&kv->lock);
128 list_for_each_entry(kvg, &kv->group_list, node) {
129 if (kvg->vfio_group != vfio_group)
132 list_del(&kvg->node);
133 kvm_vfio_group_put_external_user(kvg->vfio_group);
139 mutex_unlock(&kv->lock);
141 kvm_vfio_group_put_external_user(vfio_group);
149 static int kvm_vfio_set_attr(struct kvm_device *dev,
150 struct kvm_device_attr *attr)
152 switch (attr->group) {
153 case KVM_DEV_VFIO_GROUP:
154 return kvm_vfio_set_group(dev, attr->attr, attr->addr);
160 static int kvm_vfio_has_attr(struct kvm_device *dev,
161 struct kvm_device_attr *attr)
163 switch (attr->group) {
164 case KVM_DEV_VFIO_GROUP:
165 switch (attr->attr) {
166 case KVM_DEV_VFIO_GROUP_ADD:
167 case KVM_DEV_VFIO_GROUP_DEL:
177 static void kvm_vfio_destroy(struct kvm_device *dev)
179 struct kvm_vfio *kv = dev->private;
180 struct kvm_vfio_group *kvg, *tmp;
182 list_for_each_entry_safe(kvg, tmp, &kv->group_list, node) {
183 kvm_vfio_group_put_external_user(kvg->vfio_group);
184 list_del(&kvg->node);
189 kfree(dev); /* alloc by kvm_ioctl_create_device, free by .destroy */
192 static int kvm_vfio_create(struct kvm_device *dev, u32 type);
194 static struct kvm_device_ops kvm_vfio_ops = {
196 .create = kvm_vfio_create,
197 .destroy = kvm_vfio_destroy,
198 .set_attr = kvm_vfio_set_attr,
199 .has_attr = kvm_vfio_has_attr,
202 static int kvm_vfio_create(struct kvm_device *dev, u32 type)
204 struct kvm_device *tmp;
207 /* Only one VFIO "device" per VM */
208 list_for_each_entry(tmp, &dev->kvm->devices, vm_node)
209 if (tmp->ops == &kvm_vfio_ops)
212 kv = kzalloc(sizeof(*kv), GFP_KERNEL);
216 INIT_LIST_HEAD(&kv->group_list);
217 mutex_init(&kv->lock);
224 static int __init kvm_vfio_ops_init(void)
226 return kvm_register_device_ops(&kvm_vfio_ops, KVM_DEV_TYPE_VFIO);
228 module_init(kvm_vfio_ops_init);