OpenCloudOS-Kernel/drivers/vfio/group.c

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// SPDX-License-Identifier: GPL-2.0-only
/*
* VFIO core
*
* Copyright (C) 2012 Red Hat, Inc. All rights reserved.
* Author: Alex Williamson <alex.williamson@redhat.com>
*
* Derived from original vfio:
* Copyright 2010 Cisco Systems, Inc. All rights reserved.
* Author: Tom Lyon, pugs@cisco.com
*/
#include <linux/vfio.h>
#include <linux/iommufd.h>
#include <linux/anon_inodes.h>
#include "vfio.h"
static struct vfio {
struct class *class;
struct list_head group_list;
struct mutex group_lock; /* locks group_list */
struct ida group_ida;
dev_t group_devt;
} vfio;
static struct vfio_device *vfio_device_get_from_name(struct vfio_group *group,
char *buf)
{
struct vfio_device *it, *device = ERR_PTR(-ENODEV);
mutex_lock(&group->device_lock);
list_for_each_entry(it, &group->device_list, group_next) {
int ret;
if (it->ops->match) {
ret = it->ops->match(it, buf);
if (ret < 0) {
device = ERR_PTR(ret);
break;
}
} else {
ret = !strcmp(dev_name(it->dev), buf);
}
if (ret && vfio_device_try_get_registration(it)) {
device = it;
break;
}
}
mutex_unlock(&group->device_lock);
return device;
}
/*
* VFIO Group fd, /dev/vfio/$GROUP
*/
static bool vfio_group_has_iommu(struct vfio_group *group)
{
lockdep_assert_held(&group->group_lock);
/*
* There can only be users if there is a container, and if there is a
* container there must be users.
*/
WARN_ON(!group->container != !group->container_users);
return group->container || group->iommufd;
}
/*
* VFIO_GROUP_UNSET_CONTAINER should fail if there are other users or
* if there was no container to unset. Since the ioctl is called on
* the group, we know that still exists, therefore the only valid
* transition here is 1->0.
*/
static int vfio_group_ioctl_unset_container(struct vfio_group *group)
{
int ret = 0;
mutex_lock(&group->group_lock);
if (!vfio_group_has_iommu(group)) {
ret = -EINVAL;
goto out_unlock;
}
if (group->container) {
if (group->container_users != 1) {
ret = -EBUSY;
goto out_unlock;
}
vfio_group_detach_container(group);
}
if (group->iommufd) {
iommufd_ctx_put(group->iommufd);
group->iommufd = NULL;
}
out_unlock:
mutex_unlock(&group->group_lock);
return ret;
}
static int vfio_group_ioctl_set_container(struct vfio_group *group,
int __user *arg)
{
struct vfio_container *container;
struct iommufd_ctx *iommufd;
struct fd f;
int ret;
int fd;
if (get_user(fd, arg))
return -EFAULT;
f = fdget(fd);
if (!f.file)
return -EBADF;
mutex_lock(&group->group_lock);
if (vfio_group_has_iommu(group)) {
ret = -EINVAL;
goto out_unlock;
}
if (!group->iommu_group) {
ret = -ENODEV;
goto out_unlock;
}
container = vfio_container_from_file(f.file);
if (container) {
ret = vfio_container_attach_group(container, group);
goto out_unlock;
}
iommufd = iommufd_ctx_from_file(f.file);
if (!IS_ERR(iommufd)) {
if (IS_ENABLED(CONFIG_VFIO_NOIOMMU) &&
group->type == VFIO_NO_IOMMU)
ret = iommufd_vfio_compat_set_no_iommu(iommufd);
else
ret = iommufd_vfio_compat_ioas_create(iommufd);
if (ret) {
iommufd_ctx_put(iommufd);
goto out_unlock;
}
group->iommufd = iommufd;
goto out_unlock;
}
/* The FD passed is not recognized. */
ret = -EBADFD;
out_unlock:
mutex_unlock(&group->group_lock);
fdput(f);
return ret;
}
static void vfio_device_group_get_kvm_safe(struct vfio_device *device)
{
spin_lock(&device->group->kvm_ref_lock);
vfio_device_get_kvm_safe(device, device->group->kvm);
spin_unlock(&device->group->kvm_ref_lock);
}
static int vfio_df_group_open(struct vfio_device_file *df)
{
struct vfio_device *device = df->device;
int ret;
mutex_lock(&device->group->group_lock);
if (!vfio_group_has_iommu(device->group)) {
ret = -EINVAL;
goto out_unlock;
}
mutex_lock(&device->dev_set->lock);
/*
* Before the first device open, get the KVM pointer currently
* associated with the group (if there is one) and obtain a reference
* now that will be held until the open_count reaches 0 again. Save
* the pointer in the device for use by drivers.
*/
if (device->open_count == 0)
vfio_device_group_get_kvm_safe(device);
df->iommufd = device->group->iommufd;
if (df->iommufd && vfio_device_is_noiommu(device) && device->open_count == 0) {
/*
* Require no compat ioas to be assigned to proceed. The basic
* statement is that the user cannot have done something that
* implies they expected translation to exist
*/
if (!capable(CAP_SYS_RAWIO) ||
vfio_iommufd_device_has_compat_ioas(device, df->iommufd))
ret = -EPERM;
else
ret = 0;
goto out_put_kvm;
}
ret = vfio_df_open(df);
if (ret)
vfio: Block device access via device fd until device is opened Allow the vfio_device file to be in a state where the device FD is opened but the device cannot be used by userspace (i.e. its .open_device() hasn't been called). This inbetween state is not used when the device FD is spawned from the group FD, however when we create the device FD directly by opening a cdev it will be opened in the blocked state. The reason for the inbetween state is that userspace only gets a FD but doesn't gain access permission until binding the FD to an iommufd. So in the blocked state, only the bind operation is allowed. Completing bind will allow user to further access the device. This is implemented by adding a flag in struct vfio_device_file to mark the blocked state and using a simple smp_load_acquire() to obtain the flag value and serialize all the device setup with the thread accessing this device. Following this lockless scheme, it can safely handle the device FD unbound->bound but it cannot handle bound->unbound. To allow this we'd need to add a lock on all the vfio ioctls which seems costly. So once device FD is bound, it remains bound until the FD is closed. Suggested-by: Jason Gunthorpe <jgg@nvidia.com> Reviewed-by: Kevin Tian <kevin.tian@intel.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Reviewed-by: Eric Auger <eric.auger@redhat.com> Tested-by: Terrence Xu <terrence.xu@intel.com> Tested-by: Nicolin Chen <nicolinc@nvidia.com> Tested-by: Matthew Rosato <mjrosato@linux.ibm.com> Tested-by: Yanting Jiang <yanting.jiang@intel.com> Tested-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com> Tested-by: Zhenzhong Duan <zhenzhong.duan@intel.com> Signed-off-by: Yi Liu <yi.l.liu@intel.com> Link: https://lore.kernel.org/r/20230718135551.6592-8-yi.l.liu@intel.com Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2023-07-18 21:55:32 +08:00
goto out_put_kvm;
if (df->iommufd && device->open_count == 1) {
ret = vfio_iommufd_compat_attach_ioas(device, df->iommufd);
if (ret)
goto out_close_device;
vfio: Block device access via device fd until device is opened Allow the vfio_device file to be in a state where the device FD is opened but the device cannot be used by userspace (i.e. its .open_device() hasn't been called). This inbetween state is not used when the device FD is spawned from the group FD, however when we create the device FD directly by opening a cdev it will be opened in the blocked state. The reason for the inbetween state is that userspace only gets a FD but doesn't gain access permission until binding the FD to an iommufd. So in the blocked state, only the bind operation is allowed. Completing bind will allow user to further access the device. This is implemented by adding a flag in struct vfio_device_file to mark the blocked state and using a simple smp_load_acquire() to obtain the flag value and serialize all the device setup with the thread accessing this device. Following this lockless scheme, it can safely handle the device FD unbound->bound but it cannot handle bound->unbound. To allow this we'd need to add a lock on all the vfio ioctls which seems costly. So once device FD is bound, it remains bound until the FD is closed. Suggested-by: Jason Gunthorpe <jgg@nvidia.com> Reviewed-by: Kevin Tian <kevin.tian@intel.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Reviewed-by: Eric Auger <eric.auger@redhat.com> Tested-by: Terrence Xu <terrence.xu@intel.com> Tested-by: Nicolin Chen <nicolinc@nvidia.com> Tested-by: Matthew Rosato <mjrosato@linux.ibm.com> Tested-by: Yanting Jiang <yanting.jiang@intel.com> Tested-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com> Tested-by: Zhenzhong Duan <zhenzhong.duan@intel.com> Signed-off-by: Yi Liu <yi.l.liu@intel.com> Link: https://lore.kernel.org/r/20230718135551.6592-8-yi.l.liu@intel.com Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2023-07-18 21:55:32 +08:00
}
/*
* Paired with smp_load_acquire() in vfio_device_fops::ioctl/
* read/write/mmap and vfio_file_has_device_access()
*/
smp_store_release(&df->access_granted, true);
mutex_unlock(&device->dev_set->lock);
mutex_unlock(&device->group->group_lock);
return 0;
out_close_device:
vfio_df_close(df);
vfio: Block device access via device fd until device is opened Allow the vfio_device file to be in a state where the device FD is opened but the device cannot be used by userspace (i.e. its .open_device() hasn't been called). This inbetween state is not used when the device FD is spawned from the group FD, however when we create the device FD directly by opening a cdev it will be opened in the blocked state. The reason for the inbetween state is that userspace only gets a FD but doesn't gain access permission until binding the FD to an iommufd. So in the blocked state, only the bind operation is allowed. Completing bind will allow user to further access the device. This is implemented by adding a flag in struct vfio_device_file to mark the blocked state and using a simple smp_load_acquire() to obtain the flag value and serialize all the device setup with the thread accessing this device. Following this lockless scheme, it can safely handle the device FD unbound->bound but it cannot handle bound->unbound. To allow this we'd need to add a lock on all the vfio ioctls which seems costly. So once device FD is bound, it remains bound until the FD is closed. Suggested-by: Jason Gunthorpe <jgg@nvidia.com> Reviewed-by: Kevin Tian <kevin.tian@intel.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Reviewed-by: Eric Auger <eric.auger@redhat.com> Tested-by: Terrence Xu <terrence.xu@intel.com> Tested-by: Nicolin Chen <nicolinc@nvidia.com> Tested-by: Matthew Rosato <mjrosato@linux.ibm.com> Tested-by: Yanting Jiang <yanting.jiang@intel.com> Tested-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com> Tested-by: Zhenzhong Duan <zhenzhong.duan@intel.com> Signed-off-by: Yi Liu <yi.l.liu@intel.com> Link: https://lore.kernel.org/r/20230718135551.6592-8-yi.l.liu@intel.com Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2023-07-18 21:55:32 +08:00
out_put_kvm:
df->iommufd = NULL;
if (device->open_count == 0)
vfio_device_put_kvm(device);
mutex_unlock(&device->dev_set->lock);
out_unlock:
mutex_unlock(&device->group->group_lock);
return ret;
}
void vfio_df_group_close(struct vfio_device_file *df)
{
struct vfio_device *device = df->device;
mutex_lock(&device->group->group_lock);
mutex_lock(&device->dev_set->lock);
vfio_df_close(df);
df->iommufd = NULL;
if (device->open_count == 0)
vfio_device_put_kvm(device);
mutex_unlock(&device->dev_set->lock);
mutex_unlock(&device->group->group_lock);
}
static struct file *vfio_device_open_file(struct vfio_device *device)
{
struct vfio_device_file *df;
struct file *filep;
int ret;
df = vfio_allocate_device_file(device);
if (IS_ERR(df)) {
ret = PTR_ERR(df);
goto err_out;
}
df->group = device->group;
ret = vfio_df_group_open(df);
if (ret)
goto err_free;
/*
* We can't use anon_inode_getfd() because we need to modify
* the f_mode flags directly to allow more than just ioctls
*/
filep = anon_inode_getfile("[vfio-device]", &vfio_device_fops,
df, O_RDWR);
if (IS_ERR(filep)) {
ret = PTR_ERR(filep);
goto err_close_device;
}
/*
* TODO: add an anon_inode interface to do this.
* Appears to be missing by lack of need rather than
* explicitly prevented. Now there's need.
*/
filep->f_mode |= (FMODE_PREAD | FMODE_PWRITE);
if (device->group->type == VFIO_NO_IOMMU)
dev_warn(device->dev, "vfio-noiommu device opened by user "
"(%s:%d)\n", current->comm, task_pid_nr(current));
/*
* On success the ref of device is moved to the file and
* put in vfio_device_fops_release()
*/
return filep;
err_close_device:
vfio_df_group_close(df);
err_free:
kfree(df);
err_out:
return ERR_PTR(ret);
}
static int vfio_group_ioctl_get_device_fd(struct vfio_group *group,
char __user *arg)
{
struct vfio_device *device;
struct file *filep;
char *buf;
int fdno;
int ret;
buf = strndup_user(arg, PAGE_SIZE);
if (IS_ERR(buf))
return PTR_ERR(buf);
device = vfio_device_get_from_name(group, buf);
kfree(buf);
if (IS_ERR(device))
return PTR_ERR(device);
fdno = get_unused_fd_flags(O_CLOEXEC);
if (fdno < 0) {
ret = fdno;
goto err_put_device;
}
filep = vfio_device_open_file(device);
if (IS_ERR(filep)) {
ret = PTR_ERR(filep);
goto err_put_fdno;
}
fd_install(fdno, filep);
return fdno;
err_put_fdno:
put_unused_fd(fdno);
err_put_device:
vfio_device_put_registration(device);
return ret;
}
static int vfio_group_ioctl_get_status(struct vfio_group *group,
struct vfio_group_status __user *arg)
{
unsigned long minsz = offsetofend(struct vfio_group_status, flags);
struct vfio_group_status status;
if (copy_from_user(&status, arg, minsz))
return -EFAULT;
if (status.argsz < minsz)
return -EINVAL;
status.flags = 0;
mutex_lock(&group->group_lock);
if (!group->iommu_group) {
mutex_unlock(&group->group_lock);
return -ENODEV;
}
/*
* With the container FD the iommu_group_claim_dma_owner() is done
* during SET_CONTAINER but for IOMMFD this is done during
* VFIO_GROUP_GET_DEVICE_FD. Meaning that with iommufd
* VFIO_GROUP_FLAGS_VIABLE could be set but GET_DEVICE_FD will fail due
* to viability.
*/
if (vfio_group_has_iommu(group))
status.flags |= VFIO_GROUP_FLAGS_CONTAINER_SET |
VFIO_GROUP_FLAGS_VIABLE;
else if (!iommu_group_dma_owner_claimed(group->iommu_group))
status.flags |= VFIO_GROUP_FLAGS_VIABLE;
mutex_unlock(&group->group_lock);
if (copy_to_user(arg, &status, minsz))
return -EFAULT;
return 0;
}
static long vfio_group_fops_unl_ioctl(struct file *filep,
unsigned int cmd, unsigned long arg)
{
struct vfio_group *group = filep->private_data;
void __user *uarg = (void __user *)arg;
switch (cmd) {
case VFIO_GROUP_GET_DEVICE_FD:
return vfio_group_ioctl_get_device_fd(group, uarg);
case VFIO_GROUP_GET_STATUS:
return vfio_group_ioctl_get_status(group, uarg);
case VFIO_GROUP_SET_CONTAINER:
return vfio_group_ioctl_set_container(group, uarg);
case VFIO_GROUP_UNSET_CONTAINER:
return vfio_group_ioctl_unset_container(group);
default:
return -ENOTTY;
}
}
int vfio_device_block_group(struct vfio_device *device)
{
struct vfio_group *group = device->group;
int ret = 0;
mutex_lock(&group->group_lock);
if (group->opened_file) {
ret = -EBUSY;
goto out_unlock;
}
group->cdev_device_open_cnt++;
out_unlock:
mutex_unlock(&group->group_lock);
return ret;
}
void vfio_device_unblock_group(struct vfio_device *device)
{
struct vfio_group *group = device->group;
mutex_lock(&group->group_lock);
group->cdev_device_open_cnt--;
mutex_unlock(&group->group_lock);
}
static int vfio_group_fops_open(struct inode *inode, struct file *filep)
{
struct vfio_group *group =
container_of(inode->i_cdev, struct vfio_group, cdev);
int ret;
mutex_lock(&group->group_lock);
/*
* drivers can be zero if this races with vfio_device_remove_group(), it
* will be stable at 0 under the group rwsem
*/
if (refcount_read(&group->drivers) == 0) {
ret = -ENODEV;
goto out_unlock;
}
if (group->type == VFIO_NO_IOMMU && !capable(CAP_SYS_RAWIO)) {
ret = -EPERM;
goto out_unlock;
}
if (group->cdev_device_open_cnt) {
ret = -EBUSY;
goto out_unlock;
}
/*
* Do we need multiple instances of the group open? Seems not.
*/
if (group->opened_file) {
ret = -EBUSY;
goto out_unlock;
}
group->opened_file = filep;
filep->private_data = group;
ret = 0;
out_unlock:
mutex_unlock(&group->group_lock);
return ret;
}
static int vfio_group_fops_release(struct inode *inode, struct file *filep)
{
struct vfio_group *group = filep->private_data;
filep->private_data = NULL;
mutex_lock(&group->group_lock);
/*
* Device FDs hold a group file reference, therefore the group release
* is only called when there are no open devices.
*/
WARN_ON(group->notifier.head);
if (group->container)
vfio_group_detach_container(group);
if (group->iommufd) {
iommufd_ctx_put(group->iommufd);
group->iommufd = NULL;
}
group->opened_file = NULL;
mutex_unlock(&group->group_lock);
return 0;
}
static const struct file_operations vfio_group_fops = {
.owner = THIS_MODULE,
.unlocked_ioctl = vfio_group_fops_unl_ioctl,
.compat_ioctl = compat_ptr_ioctl,
.open = vfio_group_fops_open,
.release = vfio_group_fops_release,
};
/*
* Group objects - create, release, get, put, search
*/
static struct vfio_group *
vfio_group_find_from_iommu(struct iommu_group *iommu_group)
{
struct vfio_group *group;
lockdep_assert_held(&vfio.group_lock);
/*
* group->iommu_group from the vfio.group_list cannot be NULL
* under the vfio.group_lock.
*/
list_for_each_entry(group, &vfio.group_list, vfio_next) {
if (group->iommu_group == iommu_group)
return group;
}
return NULL;
}
static void vfio_group_release(struct device *dev)
{
struct vfio_group *group = container_of(dev, struct vfio_group, dev);
mutex_destroy(&group->device_lock);
mutex_destroy(&group->group_lock);
WARN_ON(group->iommu_group);
WARN_ON(group->cdev_device_open_cnt);
ida_free(&vfio.group_ida, MINOR(group->dev.devt));
kfree(group);
}
static struct vfio_group *vfio_group_alloc(struct iommu_group *iommu_group,
enum vfio_group_type type)
{
struct vfio_group *group;
int minor;
group = kzalloc(sizeof(*group), GFP_KERNEL);
if (!group)
return ERR_PTR(-ENOMEM);
minor = ida_alloc_max(&vfio.group_ida, MINORMASK, GFP_KERNEL);
if (minor < 0) {
kfree(group);
return ERR_PTR(minor);
}
device_initialize(&group->dev);
group->dev.devt = MKDEV(MAJOR(vfio.group_devt), minor);
group->dev.class = vfio.class;
group->dev.release = vfio_group_release;
cdev_init(&group->cdev, &vfio_group_fops);
group->cdev.owner = THIS_MODULE;
refcount_set(&group->drivers, 1);
mutex_init(&group->group_lock);
spin_lock_init(&group->kvm_ref_lock);
INIT_LIST_HEAD(&group->device_list);
mutex_init(&group->device_lock);
group->iommu_group = iommu_group;
/* put in vfio_group_release() */
iommu_group_ref_get(iommu_group);
group->type = type;
BLOCKING_INIT_NOTIFIER_HEAD(&group->notifier);
return group;
}
static struct vfio_group *vfio_create_group(struct iommu_group *iommu_group,
enum vfio_group_type type)
{
struct vfio_group *group;
struct vfio_group *ret;
int err;
lockdep_assert_held(&vfio.group_lock);
group = vfio_group_alloc(iommu_group, type);
if (IS_ERR(group))
return group;
err = dev_set_name(&group->dev, "%s%d",
group->type == VFIO_NO_IOMMU ? "noiommu-" : "",
iommu_group_id(iommu_group));
if (err) {
ret = ERR_PTR(err);
goto err_put;
}
err = cdev_device_add(&group->cdev, &group->dev);
if (err) {
ret = ERR_PTR(err);
goto err_put;
}
list_add(&group->vfio_next, &vfio.group_list);
return group;
err_put:
put_device(&group->dev);
return ret;
}
static struct vfio_group *vfio_noiommu_group_alloc(struct device *dev,
enum vfio_group_type type)
{
struct iommu_group *iommu_group;
struct vfio_group *group;
int ret;
iommu_group = iommu_group_alloc();
if (IS_ERR(iommu_group))
return ERR_CAST(iommu_group);
ret = iommu_group_set_name(iommu_group, "vfio-noiommu");
if (ret)
goto out_put_group;
ret = iommu_group_add_device(iommu_group, dev);
if (ret)
goto out_put_group;
mutex_lock(&vfio.group_lock);
group = vfio_create_group(iommu_group, type);
mutex_unlock(&vfio.group_lock);
if (IS_ERR(group)) {
ret = PTR_ERR(group);
goto out_remove_device;
}
iommu_group_put(iommu_group);
return group;
out_remove_device:
iommu_group_remove_device(dev);
out_put_group:
iommu_group_put(iommu_group);
return ERR_PTR(ret);
}
static bool vfio_group_has_device(struct vfio_group *group, struct device *dev)
{
struct vfio_device *device;
mutex_lock(&group->device_lock);
list_for_each_entry(device, &group->device_list, group_next) {
if (device->dev == dev) {
mutex_unlock(&group->device_lock);
return true;
}
}
mutex_unlock(&group->device_lock);
return false;
}
static struct vfio_group *vfio_group_find_or_alloc(struct device *dev)
{
struct iommu_group *iommu_group;
struct vfio_group *group;
iommu_group = iommu_group_get(dev);
if (!iommu_group && vfio_noiommu) {
/*
* With noiommu enabled, create an IOMMU group for devices that
* don't already have one, implying no IOMMU hardware/driver
* exists. Taint the kernel because we're about to give a DMA
* capable device to a user without IOMMU protection.
*/
group = vfio_noiommu_group_alloc(dev, VFIO_NO_IOMMU);
if (!IS_ERR(group)) {
add_taint(TAINT_USER, LOCKDEP_STILL_OK);
dev_warn(dev, "Adding kernel taint for vfio-noiommu group on device\n");
}
return group;
}
if (!iommu_group)
return ERR_PTR(-EINVAL);
mutex_lock(&vfio.group_lock);
group = vfio_group_find_from_iommu(iommu_group);
if (group) {
if (WARN_ON(vfio_group_has_device(group, dev)))
group = ERR_PTR(-EINVAL);
else
refcount_inc(&group->drivers);
} else {
group = vfio_create_group(iommu_group, VFIO_IOMMU);
}
mutex_unlock(&vfio.group_lock);
/* The vfio_group holds a reference to the iommu_group */
iommu_group_put(iommu_group);
return group;
}
int vfio_device_set_group(struct vfio_device *device,
enum vfio_group_type type)
{
struct vfio_group *group;
if (type == VFIO_IOMMU)
group = vfio_group_find_or_alloc(device->dev);
else
group = vfio_noiommu_group_alloc(device->dev, type);
if (IS_ERR(group))
return PTR_ERR(group);
/* Our reference on group is moved to the device */
device->group = group;
return 0;
}
void vfio_device_remove_group(struct vfio_device *device)
{
struct vfio_group *group = device->group;
struct iommu_group *iommu_group;
if (group->type == VFIO_NO_IOMMU || group->type == VFIO_EMULATED_IOMMU)
iommu_group_remove_device(device->dev);
/* Pairs with vfio_create_group() / vfio_group_get_from_iommu() */
if (!refcount_dec_and_mutex_lock(&group->drivers, &vfio.group_lock))
return;
list_del(&group->vfio_next);
/*
* We could concurrently probe another driver in the group that might
* race vfio_device_remove_group() with vfio_get_group(), so we have to
* ensure that the sysfs is all cleaned up under lock otherwise the
* cdev_device_add() will fail due to the name aready existing.
*/
cdev_device_del(&group->cdev, &group->dev);
mutex_lock(&group->group_lock);
/*
* These data structures all have paired operations that can only be
* undone when the caller holds a live reference on the device. Since
* all pairs must be undone these WARN_ON's indicate some caller did not
* properly hold the group reference.
*/
WARN_ON(!list_empty(&group->device_list));
WARN_ON(group->notifier.head);
/*
* Revoke all users of group->iommu_group. At this point we know there
* are no devices active because we are unplugging the last one. Setting
* iommu_group to NULL blocks all new users.
*/
if (group->container)
vfio_group_detach_container(group);
iommu_group = group->iommu_group;
group->iommu_group = NULL;
mutex_unlock(&group->group_lock);
mutex_unlock(&vfio.group_lock);
iommu_group_put(iommu_group);
put_device(&group->dev);
}
void vfio_device_group_register(struct vfio_device *device)
{
mutex_lock(&device->group->device_lock);
list_add(&device->group_next, &device->group->device_list);
mutex_unlock(&device->group->device_lock);
}
void vfio_device_group_unregister(struct vfio_device *device)
{
mutex_lock(&device->group->device_lock);
list_del(&device->group_next);
mutex_unlock(&device->group->device_lock);
}
int vfio_device_group_use_iommu(struct vfio_device *device)
{
struct vfio_group *group = device->group;
int ret = 0;
lockdep_assert_held(&group->group_lock);
if (WARN_ON(!group->container))
return -EINVAL;
ret = vfio_group_use_container(group);
if (ret)
return ret;
vfio_device_container_register(device);
return 0;
}
void vfio_device_group_unuse_iommu(struct vfio_device *device)
{
struct vfio_group *group = device->group;
lockdep_assert_held(&group->group_lock);
if (WARN_ON(!group->container))
return;
vfio_device_container_unregister(device);
vfio_group_unuse_container(group);
}
bool vfio_device_has_container(struct vfio_device *device)
{
return device->group->container;
}
struct vfio_group *vfio_group_from_file(struct file *file)
{
struct vfio_group *group = file->private_data;
if (file->f_op != &vfio_group_fops)
return NULL;
return group;
}
/**
* vfio_file_iommu_group - Return the struct iommu_group for the vfio group file
* @file: VFIO group file
*
* The returned iommu_group is valid as long as a ref is held on the file. This
* returns a reference on the group. This function is deprecated, only the SPAPR
* path in kvm should call it.
*/
struct iommu_group *vfio_file_iommu_group(struct file *file)
{
struct vfio_group *group = vfio_group_from_file(file);
struct iommu_group *iommu_group = NULL;
if (!IS_ENABLED(CONFIG_SPAPR_TCE_IOMMU))
return NULL;
if (!group)
return NULL;
mutex_lock(&group->group_lock);
if (group->iommu_group) {
iommu_group = group->iommu_group;
iommu_group_ref_get(iommu_group);
}
mutex_unlock(&group->group_lock);
return iommu_group;
}
EXPORT_SYMBOL_GPL(vfio_file_iommu_group);
/**
* vfio_file_is_group - True if the file is a vfio group file
* @file: VFIO group file
*/
bool vfio_file_is_group(struct file *file)
{
return vfio_group_from_file(file);
}
EXPORT_SYMBOL_GPL(vfio_file_is_group);
bool vfio_group_enforced_coherent(struct vfio_group *group)
{
struct vfio_device *device;
bool ret = true;
/*
* If the device does not have IOMMU_CAP_ENFORCE_CACHE_COHERENCY then
* any domain later attached to it will also not support it. If the cap
* is set then the iommu_domain eventually attached to the device/group
* must use a domain with enforce_cache_coherency().
*/
mutex_lock(&group->device_lock);
list_for_each_entry(device, &group->device_list, group_next) {
if (!device_iommu_capable(device->dev,
IOMMU_CAP_ENFORCE_CACHE_COHERENCY)) {
ret = false;
break;
}
}
mutex_unlock(&group->device_lock);
return ret;
}
void vfio_group_set_kvm(struct vfio_group *group, struct kvm *kvm)
{
spin_lock(&group->kvm_ref_lock);
group->kvm = kvm;
spin_unlock(&group->kvm_ref_lock);
}
/**
* vfio_file_has_dev - True if the VFIO file is a handle for device
* @file: VFIO file to check
* @device: Device that must be part of the file
*
* Returns true if given file has permission to manipulate the given device.
*/
bool vfio_file_has_dev(struct file *file, struct vfio_device *device)
{
struct vfio_group *group = vfio_group_from_file(file);
if (!group)
return false;
return group == device->group;
}
EXPORT_SYMBOL_GPL(vfio_file_has_dev);
Driver Core changes for 6.2-rc1 Here is the set of driver core and kernfs changes for 6.2-rc1. The "big" change in here is the addition of a new macro, container_of_const() that will preserve the "const-ness" of a pointer passed into it. The "problem" of the current container_of() macro is that if you pass in a "const *", out of it can comes a non-const pointer unless you specifically ask for it. For many usages, we want to preserve the "const" attribute by using the same call. For a specific example, this series changes the kobj_to_dev() macro to use it, allowing it to be used no matter what the const value is. This prevents every subsystem from having to declare 2 different individual macros (i.e. kobj_const_to_dev() and kobj_to_dev()) and having the compiler enforce the const value at build time, which having 2 macros would not do either. The driver for all of this have been discussions with the Rust kernel developers as to how to properly mark driver core, and kobject, objects as being "non-mutable". The changes to the kobject and driver core in this pull request are the result of that, as there are lots of paths where kobjects and device pointers are not modified at all, so marking them as "const" allows the compiler to enforce this. So, a nice side affect of the Rust development effort has been already to clean up the driver core code to be more obvious about object rules. All of this has been bike-shedded in quite a lot of detail on lkml with different names and implementations resulting in the tiny version we have in here, much better than my original proposal. Lots of subsystem maintainers have acked the changes as well. Other than this change, included in here are smaller stuff like: - kernfs fixes and updates to handle lock contention better - vmlinux.lds.h fixes and updates - sysfs and debugfs documentation updates - device property updates All of these have been in the linux-next tree for quite a while with no problems, OTHER than some merge issues with other trees that should be obvious when you hit them (block tree deletes a driver that this tree modifies, iommufd tree modifies code that this tree also touches). If there are merge problems with these trees, please let me know. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> -----BEGIN PGP SIGNATURE----- iG0EABECAC0WIQT0tgzFv3jCIUoxPcsxR9QN2y37KQUCY5wz3A8cZ3JlZ0Brcm9h aC5jb20ACgkQMUfUDdst+yks0ACeKYUlVgCsER8eYW+x18szFa2QTXgAn2h/VhZe 1Fp53boFaQkGBjl8mGF8 =v+FB -----END PGP SIGNATURE----- Merge tag 'driver-core-6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core Pull driver core updates from Greg KH: "Here is the set of driver core and kernfs changes for 6.2-rc1. The "big" change in here is the addition of a new macro, container_of_const() that will preserve the "const-ness" of a pointer passed into it. The "problem" of the current container_of() macro is that if you pass in a "const *", out of it can comes a non-const pointer unless you specifically ask for it. For many usages, we want to preserve the "const" attribute by using the same call. For a specific example, this series changes the kobj_to_dev() macro to use it, allowing it to be used no matter what the const value is. This prevents every subsystem from having to declare 2 different individual macros (i.e. kobj_const_to_dev() and kobj_to_dev()) and having the compiler enforce the const value at build time, which having 2 macros would not do either. The driver for all of this have been discussions with the Rust kernel developers as to how to properly mark driver core, and kobject, objects as being "non-mutable". The changes to the kobject and driver core in this pull request are the result of that, as there are lots of paths where kobjects and device pointers are not modified at all, so marking them as "const" allows the compiler to enforce this. So, a nice side affect of the Rust development effort has been already to clean up the driver core code to be more obvious about object rules. All of this has been bike-shedded in quite a lot of detail on lkml with different names and implementations resulting in the tiny version we have in here, much better than my original proposal. Lots of subsystem maintainers have acked the changes as well. Other than this change, included in here are smaller stuff like: - kernfs fixes and updates to handle lock contention better - vmlinux.lds.h fixes and updates - sysfs and debugfs documentation updates - device property updates All of these have been in the linux-next tree for quite a while with no problems" * tag 'driver-core-6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (58 commits) device property: Fix documentation for fwnode_get_next_parent() firmware_loader: fix up to_fw_sysfs() to preserve const usb.h: take advantage of container_of_const() device.h: move kobj_to_dev() to use container_of_const() container_of: add container_of_const() that preserves const-ness of the pointer driver core: fix up missed drivers/s390/char/hmcdrv_dev.c class.devnode() conversion. driver core: fix up missed scsi/cxlflash class.devnode() conversion. driver core: fix up some missing class.devnode() conversions. driver core: make struct class.devnode() take a const * driver core: make struct class.dev_uevent() take a const * cacheinfo: Remove of_node_put() for fw_token device property: Add a blank line in Kconfig of tests device property: Rename goto label to be more precise device property: Move PROPERTY_ENTRY_BOOL() a bit down device property: Get rid of __PROPERTY_ENTRY_ARRAY_EL*SIZE*() kernfs: fix all kernel-doc warnings and multiple typos driver core: pass a const * into of_device_uevent() kobject: kset_uevent_ops: make name() callback take a const * kobject: kset_uevent_ops: make filter() callback take a const * kobject: make kobject_namespace take a const * ...
2022-12-16 19:54:54 +08:00
static char *vfio_devnode(const struct device *dev, umode_t *mode)
{
return kasprintf(GFP_KERNEL, "vfio/%s", dev_name(dev));
}
int __init vfio_group_init(void)
{
int ret;
ida_init(&vfio.group_ida);
mutex_init(&vfio.group_lock);
INIT_LIST_HEAD(&vfio.group_list);
ret = vfio_container_init();
if (ret)
return ret;
/* /dev/vfio/$GROUP */
vfio.class = class_create("vfio");
if (IS_ERR(vfio.class)) {
ret = PTR_ERR(vfio.class);
goto err_group_class;
}
vfio.class->devnode = vfio_devnode;
ret = alloc_chrdev_region(&vfio.group_devt, 0, MINORMASK + 1, "vfio");
if (ret)
goto err_alloc_chrdev;
return 0;
err_alloc_chrdev:
class_destroy(vfio.class);
vfio.class = NULL;
err_group_class:
vfio_container_cleanup();
return ret;
}
void vfio_group_cleanup(void)
{
WARN_ON(!list_empty(&vfio.group_list));
ida_destroy(&vfio.group_ida);
unregister_chrdev_region(vfio.group_devt, MINORMASK + 1);
class_destroy(vfio.class);
vfio.class = NULL;
vfio_container_cleanup();
}