diff options
Diffstat (limited to 'virt/kvm/vfio.c')
| -rw-r--r-- | virt/kvm/vfio.c | 220 |
1 files changed, 220 insertions, 0 deletions
diff --git a/virt/kvm/vfio.c b/virt/kvm/vfio.c new file mode 100644 index 000000000000..597c258245ea --- /dev/null +++ b/virt/kvm/vfio.c @@ -0,0 +1,220 @@ +/* + * VFIO-KVM bridge pseudo device + * + * Copyright (C) 2013 Red Hat, Inc. All rights reserved. + * Author: Alex Williamson <alex.williamson@redhat.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/errno.h> +#include <linux/file.h> +#include <linux/kvm_host.h> +#include <linux/list.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/slab.h> +#include <linux/uaccess.h> +#include <linux/vfio.h> + +struct kvm_vfio_group { + struct list_head node; + struct vfio_group *vfio_group; +}; + +struct kvm_vfio { + struct list_head group_list; + struct mutex lock; +}; + +static struct vfio_group *kvm_vfio_group_get_external_user(struct file *filep) +{ + struct vfio_group *vfio_group; + struct vfio_group *(*fn)(struct file *); + + fn = symbol_get(vfio_group_get_external_user); + if (!fn) + return ERR_PTR(-EINVAL); + + vfio_group = fn(filep); + + symbol_put(vfio_group_get_external_user); + + return vfio_group; +} + +static void kvm_vfio_group_put_external_user(struct vfio_group *vfio_group) +{ + void (*fn)(struct vfio_group *); + + fn = symbol_get(vfio_group_put_external_user); + if (!fn) + return; + + fn(vfio_group); + + symbol_put(vfio_group_put_external_user); +} + +static int kvm_vfio_set_group(struct kvm_device *dev, long attr, u64 arg) +{ + struct kvm_vfio *kv = dev->private; + struct vfio_group *vfio_group; + struct kvm_vfio_group *kvg; + void __user *argp = (void __user *)arg; + struct fd f; + int32_t fd; + int ret; + + switch (attr) { + case KVM_DEV_VFIO_GROUP_ADD: + if (get_user(fd, (int32_t __user *)argp)) + return -EFAULT; + + f = fdget(fd); + if (!f.file) + return -EBADF; + + vfio_group = kvm_vfio_group_get_external_user(f.file); + fdput(f); + + if (IS_ERR(vfio_group)) + return PTR_ERR(vfio_group); + + mutex_lock(&kv->lock); + + list_for_each_entry(kvg, &kv->group_list, node) { + if (kvg->vfio_group == vfio_group) { + mutex_unlock(&kv->lock); + kvm_vfio_group_put_external_user(vfio_group); + return -EEXIST; + } + } + + kvg = kzalloc(sizeof(*kvg), GFP_KERNEL); + if (!kvg) { + mutex_unlock(&kv->lock); + kvm_vfio_group_put_external_user(vfio_group); + return -ENOMEM; + } + + list_add_tail(&kvg->node, &kv->group_list); + kvg->vfio_group = vfio_group; + + mutex_unlock(&kv->lock); + + return 0; + + case KVM_DEV_VFIO_GROUP_DEL: + if (get_user(fd, (int32_t __user *)argp)) + return -EFAULT; + + f = fdget(fd); + if (!f.file) + return -EBADF; + + vfio_group = kvm_vfio_group_get_external_user(f.file); + fdput(f); + + if (IS_ERR(vfio_group)) + return PTR_ERR(vfio_group); + + ret = -ENOENT; + + mutex_lock(&kv->lock); + + list_for_each_entry(kvg, &kv->group_list, node) { + if (kvg->vfio_group != vfio_group) + continue; + + list_del(&kvg->node); + kvm_vfio_group_put_external_user(kvg->vfio_group); + kfree(kvg); + ret = 0; + break; + } + + mutex_unlock(&kv->lock); + + kvm_vfio_group_put_external_user(vfio_group); + + return ret; + } + + return -ENXIO; +} + +static int kvm_vfio_set_attr(struct kvm_device *dev, + struct kvm_device_attr *attr) +{ + switch (attr->group) { + case KVM_DEV_VFIO_GROUP: + return kvm_vfio_set_group(dev, attr->attr, attr->addr); + } + + return -ENXIO; +} + +static int kvm_vfio_has_attr(struct kvm_device *dev, + struct kvm_device_attr *attr) +{ + switch (attr->group) { + case KVM_DEV_VFIO_GROUP: + switch (attr->attr) { + case KVM_DEV_VFIO_GROUP_ADD: + case KVM_DEV_VFIO_GROUP_DEL: + return 0; + } + + break; + } + + return -ENXIO; +} + +static void kvm_vfio_destroy(struct kvm_device *dev) +{ + struct kvm_vfio *kv = dev->private; + struct kvm_vfio_group *kvg, *tmp; + + list_for_each_entry_safe(kvg, tmp, &kv->group_list, node) { + kvm_vfio_group_put_external_user(kvg->vfio_group); + list_del(&kvg->node); + kfree(kvg); + } + + kfree(kv); + kfree(dev); /* alloc by kvm_ioctl_create_device, free by .destroy */ +} + +static int kvm_vfio_create(struct kvm_device *dev, u32 type) +{ + struct kvm_device *tmp; + struct kvm_vfio *kv; + + /* Only one VFIO "device" per VM */ + list_for_each_entry(tmp, &dev->kvm->devices, vm_node) + if (tmp->ops == &kvm_vfio_ops) + return -EBUSY; + + kv = kzalloc(sizeof(*kv), GFP_KERNEL); + if (!kv) + return -ENOMEM; + + INIT_LIST_HEAD(&kv->group_list); + mutex_init(&kv->lock); + + dev->private = kv; + + return 0; +} + +struct kvm_device_ops kvm_vfio_ops = { + .name = "kvm-vfio", + .create = kvm_vfio_create, + .destroy = kvm_vfio_destroy, + .set_attr = kvm_vfio_set_attr, + .has_attr = kvm_vfio_has_attr, +}; |