linux/virt/kvm/vfio.c

426 lines
8.8 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* VFIO-KVM bridge pseudo device
*
* Copyright (C) 2013 Red Hat, Inc. All rights reserved.
* Author: Alex Williamson <alex.williamson@redhat.com>
*/
#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>
#include "vfio.h"
#ifdef CONFIG_SPAPR_TCE_IOMMU
#include <asm/kvm_ppc.h>
#endif
struct kvm_vfio_group {
struct list_head node;
struct vfio_group *vfio_group;
};
struct kvm_vfio {
struct list_head group_list;
struct mutex lock;
bool noncoherent;
};
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 bool kvm_vfio_external_group_match_file(struct vfio_group *group,
struct file *filep)
{
bool ret, (*fn)(struct vfio_group *, struct file *);
fn = symbol_get(vfio_external_group_match_file);
if (!fn)
return false;
ret = fn(group, filep);
symbol_put(vfio_external_group_match_file);
return ret;
}
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 void kvm_vfio_group_set_kvm(struct vfio_group *group, struct kvm *kvm)
{
void (*fn)(struct vfio_group *, struct kvm *);
fn = symbol_get(vfio_group_set_kvm);
if (!fn)
return;
fn(group, kvm);
symbol_put(vfio_group_set_kvm);
}
static bool kvm_vfio_group_is_coherent(struct vfio_group *vfio_group)
{
long (*fn)(struct vfio_group *, unsigned long);
long ret;
fn = symbol_get(vfio_external_check_extension);
if (!fn)
return false;
ret = fn(vfio_group, VFIO_DMA_CC_IOMMU);
symbol_put(vfio_external_check_extension);
return ret > 0;
}
#ifdef CONFIG_SPAPR_TCE_IOMMU
static int kvm_vfio_external_user_iommu_id(struct vfio_group *vfio_group)
{
int (*fn)(struct vfio_group *);
int ret = -EINVAL;
fn = symbol_get(vfio_external_user_iommu_id);
if (!fn)
return ret;
ret = fn(vfio_group);
symbol_put(vfio_external_user_iommu_id);
return ret;
}
static struct iommu_group *kvm_vfio_group_get_iommu_group(
struct vfio_group *group)
{
int group_id = kvm_vfio_external_user_iommu_id(group);
if (group_id < 0)
return NULL;
return iommu_group_get_by_id(group_id);
}
static void kvm_spapr_tce_release_vfio_group(struct kvm *kvm,
struct vfio_group *vfio_group)
{
struct iommu_group *grp = kvm_vfio_group_get_iommu_group(vfio_group);
if (WARN_ON_ONCE(!grp))
return;
kvm_spapr_tce_release_iommu_group(kvm, grp);
iommu_group_put(grp);
}
#endif
/*
* Groups can use the same or different IOMMU domains. If the same then
* adding a new group may change the coherency of groups we've previously
* been told about. We don't want to care about any of that so we retest
* each group and bail as soon as we find one that's noncoherent. This
* means we only ever [un]register_noncoherent_dma once for the whole device.
*/
static void kvm_vfio_update_coherency(struct kvm_device *dev)
{
struct kvm_vfio *kv = dev->private;
bool noncoherent = false;
struct kvm_vfio_group *kvg;
mutex_lock(&kv->lock);
list_for_each_entry(kvg, &kv->group_list, node) {
if (!kvm_vfio_group_is_coherent(kvg->vfio_group)) {
noncoherent = true;
break;
}
}
if (noncoherent != kv->noncoherent) {
kv->noncoherent = noncoherent;
if (kv->noncoherent)
kvm_arch_register_noncoherent_dma(dev->kvm);
else
kvm_arch_unregister_noncoherent_dma(dev->kvm);
}
mutex_unlock(&kv->lock);
}
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;
int32_t __user *argp = (int32_t __user *)(unsigned long)arg;
struct fd f;
int32_t fd;
int ret;
switch (attr) {
case KVM_DEV_VFIO_GROUP_ADD:
if (get_user(fd, 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_ACCOUNT);
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;
kvm_arch_start_assignment(dev->kvm);
mutex_unlock(&kv->lock);
kvm_vfio_group_set_kvm(vfio_group, dev->kvm);
kvm_vfio_update_coherency(dev);
return 0;
case KVM_DEV_VFIO_GROUP_DEL:
if (get_user(fd, argp))
return -EFAULT;
f = fdget(fd);
if (!f.file)
return -EBADF;
ret = -ENOENT;
mutex_lock(&kv->lock);
list_for_each_entry(kvg, &kv->group_list, node) {
if (!kvm_vfio_external_group_match_file(kvg->vfio_group,
f.file))
continue;
list_del(&kvg->node);
kvm_arch_end_assignment(dev->kvm);
#ifdef CONFIG_SPAPR_TCE_IOMMU
kvm_spapr_tce_release_vfio_group(dev->kvm,
kvg->vfio_group);
#endif
kvm_vfio_group_set_kvm(kvg->vfio_group, NULL);
kvm_vfio_group_put_external_user(kvg->vfio_group);
kfree(kvg);
ret = 0;
break;
}
mutex_unlock(&kv->lock);
fdput(f);
kvm_vfio_update_coherency(dev);
return ret;
#ifdef CONFIG_SPAPR_TCE_IOMMU
case KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE: {
struct kvm_vfio_spapr_tce param;
struct kvm_vfio *kv = dev->private;
struct vfio_group *vfio_group;
struct kvm_vfio_group *kvg;
struct fd f;
struct iommu_group *grp;
if (copy_from_user(&param, (void __user *)arg,
sizeof(struct kvm_vfio_spapr_tce)))
return -EFAULT;
f = fdget(param.groupfd);
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);
grp = kvm_vfio_group_get_iommu_group(vfio_group);
if (WARN_ON_ONCE(!grp)) {
kvm_vfio_group_put_external_user(vfio_group);
return -EIO;
}
ret = -ENOENT;
mutex_lock(&kv->lock);
list_for_each_entry(kvg, &kv->group_list, node) {
if (kvg->vfio_group != vfio_group)
continue;
ret = kvm_spapr_tce_attach_iommu_group(dev->kvm,
param.tablefd, grp);
break;
}
mutex_unlock(&kv->lock);
iommu_group_put(grp);
kvm_vfio_group_put_external_user(vfio_group);
return ret;
}
#endif /* CONFIG_SPAPR_TCE_IOMMU */
}
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:
#ifdef CONFIG_SPAPR_TCE_IOMMU
case KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE:
#endif
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) {
#ifdef CONFIG_SPAPR_TCE_IOMMU
kvm_spapr_tce_release_vfio_group(dev->kvm, kvg->vfio_group);
#endif
kvm_vfio_group_set_kvm(kvg->vfio_group, NULL);
kvm_vfio_group_put_external_user(kvg->vfio_group);
list_del(&kvg->node);
kfree(kvg);
kvm_arch_end_assignment(dev->kvm);
}
kvm_vfio_update_coherency(dev);
kfree(kv);
kfree(dev); /* alloc by kvm_ioctl_create_device, free by .destroy */
}
static int kvm_vfio_create(struct kvm_device *dev, u32 type);
static 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,
};
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_ACCOUNT);
if (!kv)
return -ENOMEM;
INIT_LIST_HEAD(&kv->group_list);
mutex_init(&kv->lock);
dev->private = kv;
return 0;
}
int kvm_vfio_ops_init(void)
{
return kvm_register_device_ops(&kvm_vfio_ops, KVM_DEV_TYPE_VFIO);
}
void kvm_vfio_ops_exit(void)
{
kvm_unregister_device_ops(KVM_DEV_TYPE_VFIO);
}