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vfio: Add struct device to vfio_device

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and replace kref. With it a 'vfio-dev/vfioX' node is created under the
sysfs path of the parent, indicating the device is bound to a vfio
driver, e.g.:

/sys/devices/pci0000\:6f/0000\:6f\:01.0/vfio-dev/vfio0

It is also a preparatory step toward adding cdev for supporting future
device-oriented uAPI.

Add Documentation/ABI/testing/sysfs-devices-vfio-dev.

Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
Signed-off-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20220921104401.38898-16-kevin.tian@intel.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
This commit is contained in:
Yi Liu 2022-09-21 18:44:01 +08:00 committed by Alex Williamson
parent 4a725b8de4
commit 3c28a76124
4 changed files with 65 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
Documentation/ABI/testing/sysfs-devices-vfio-dev Normal file
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@ -0,0 +1,8 @@
What: /sys/.../<device>/vfio-dev/vfioX/
Date: September 2022
Contact: Yi Liu <yi.l.liu@intel.com>
Description:
This directory is created when the device is bound to a
vfio driver. The layout under this directory matches what
exists for a standard 'struct device'. 'X' is a unique
index marking this device in vfio.

1
MAINTAINERS
View File

@ -21312,6 +21312,7 @@ R: Cornelia Huck <cohuck@redhat.com>
L: kvm@vger.kernel.org
S: Maintained
T: git git://github.com/awilliam/linux-vfio.git
F: Documentation/ABI/testing/sysfs-devices-vfio-dev
F: Documentation/driver-api/vfio.rst
F: drivers/vfio/
F: include/linux/vfio.h

64
drivers/vfio/vfio_main.c
View File

@ -49,6 +49,8 @@ static struct vfio {
struct mutex group_lock; /* locks group_list */
struct ida group_ida;
dev_t group_devt;
struct class *device_class;
struct ida device_ida;
} vfio;
struct vfio_iommu_driver {
@ -485,12 +487,13 @@ static struct vfio_device *vfio_group_get_device(struct vfio_group *group,
* VFIO driver API
*/
/* Release helper called by vfio_put_device() */
void vfio_device_release(struct kref *kref)
static void vfio_device_release(struct device *dev)
{
struct vfio_device *device =
container_of(kref, struct vfio_device, kref);
container_of(dev, struct vfio_device, device);
vfio_release_device_set(device);
ida_free(&vfio.device_ida, device->index);
/*
* kvfree() cannot be done here due to a life cycle mess in
@ -500,7 +503,6 @@ void vfio_device_release(struct kref *kref)
*/
device->ops->release(device);
}
EXPORT_SYMBOL_GPL(vfio_device_release);
/*
* Allocate and initialize vfio_device so it can be registered to vfio
@ -548,6 +550,13 @@ int vfio_init_device(struct vfio_device *device, struct device *dev,
{
int ret;
ret = ida_alloc_max(&vfio.device_ida, MINORMASK, GFP_KERNEL);
if (ret < 0) {
dev_dbg(dev, "Error to alloc index\n");
return ret;
}
device->index = ret;
init_completion(&device->comp);
device->dev = dev;
device->ops = ops;
@ -558,11 +567,15 @@ int vfio_init_device(struct vfio_device *device, struct device *dev,
goto out_uninit;
}
kref_init(&device->kref);
device_initialize(&device->device);
device->device.release = vfio_device_release;
device->device.class = vfio.device_class;
device->device.parent = device->dev;
return 0;
out_uninit:
vfio_release_device_set(device);
ida_free(&vfio.device_ida, device->index);
return ret;
}
EXPORT_SYMBOL_GPL(vfio_init_device);
@ -659,6 +672,7 @@ static int __vfio_register_dev(struct vfio_device *device,
struct vfio_group *group)
{
struct vfio_device *existing_device;
int ret;
if (IS_ERR(group))
return PTR_ERR(group);
@ -675,16 +689,21 @@ static int __vfio_register_dev(struct vfio_device *device,
dev_WARN(device->dev, "Device already exists on group %d\n",
iommu_group_id(group->iommu_group));
vfio_device_put_registration(existing_device);
if (group->type == VFIO_NO_IOMMU ||
group->type == VFIO_EMULATED_IOMMU)
iommu_group_remove_device(device->dev);
vfio_group_put(group);
return -EBUSY;
ret = -EBUSY;
goto err_out;
}
/* Our reference on group is moved to the device */
device->group = group;
ret = dev_set_name(&device->device, "vfio%d", device->index);
if (ret)
goto err_out;
ret = device_add(&device->device);
if (ret)
goto err_out;
/* Refcounting can't start until the driver calls register */
refcount_set(&device->refcount, 1);
@ -693,6 +712,12 @@ static int __vfio_register_dev(struct vfio_device *device,
mutex_unlock(&group->device_lock);
return 0;
err_out:
if (group->type == VFIO_NO_IOMMU ||
group->type == VFIO_EMULATED_IOMMU)
iommu_group_remove_device(device->dev);
vfio_group_put(group);
return ret;
}
int vfio_register_group_dev(struct vfio_device *device)
@ -779,6 +804,9 @@ void vfio_unregister_group_dev(struct vfio_device *device)
list_del(&device->group_next);
mutex_unlock(&group->device_lock);
/* Balances device_add in register path */
device_del(&device->device);
if (group->type == VFIO_NO_IOMMU || group->type == VFIO_EMULATED_IOMMU)
iommu_group_remove_device(device->dev);
@ -2362,6 +2390,7 @@ static int __init vfio_init(void)
int ret;
ida_init(&vfio.group_ida);
ida_init(&vfio.device_ida);
mutex_init(&vfio.group_lock);
mutex_init(&vfio.iommu_drivers_lock);
INIT_LIST_HEAD(&vfio.group_list);
@ -2377,11 +2406,18 @@ static int __init vfio_init(void)
vfio.class = class_create(THIS_MODULE, "vfio");
if (IS_ERR(vfio.class)) {
ret = PTR_ERR(vfio.class);
goto err_class;
goto err_group_class;
}
vfio.class->devnode = vfio_devnode;
/* /sys/class/vfio-dev/vfioX */
vfio.device_class = class_create(THIS_MODULE, "vfio-dev");
if (IS_ERR(vfio.device_class)) {
ret = PTR_ERR(vfio.device_class);
goto err_dev_class;
}
ret = alloc_chrdev_region(&vfio.group_devt, 0, MINORMASK + 1, "vfio");
if (ret)
goto err_alloc_chrdev;
@ -2398,9 +2434,12 @@ static int __init vfio_init(void)
err_driver_register:
unregister_chrdev_region(vfio.group_devt, MINORMASK + 1);
err_alloc_chrdev:
class_destroy(vfio.device_class);
vfio.device_class = NULL;
err_dev_class:
class_destroy(vfio.class);
vfio.class = NULL;
err_class:
err_group_class:
misc_deregister(&vfio_dev);
return ret;
}
@ -2412,8 +2451,11 @@ static void __exit vfio_cleanup(void)
#ifdef CONFIG_VFIO_NOIOMMU
vfio_unregister_iommu_driver(&vfio_noiommu_ops);
#endif
ida_destroy(&vfio.device_ida);
ida_destroy(&vfio.group_ida);
unregister_chrdev_region(vfio.group_devt, MINORMASK + 1);
class_destroy(vfio.device_class);
vfio.device_class = NULL;
class_destroy(vfio.class);
vfio.class = NULL;
misc_deregister(&vfio_dev);

6
include/linux/vfio.h
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@ -47,7 +47,8 @@ struct vfio_device {
struct kvm *kvm;
/* Members below here are private, not for driver use */
struct kref kref; /* object life cycle */
unsigned int index;
struct device device; /* device.kref covers object life circle */
refcount_t refcount; /* user count on registered device*/
unsigned int open_count;
struct completion comp;
@ -178,10 +179,9 @@ struct vfio_device *_vfio_alloc_device(size_t size, struct device *dev,
int vfio_init_device(struct vfio_device *device, struct device *dev,
const struct vfio_device_ops *ops);
void vfio_free_device(struct vfio_device *device);
void vfio_device_release(struct kref *kref);
static inline void vfio_put_device(struct vfio_device *device)
{
kref_put(&device->kref, vfio_device_release);
put_device(&device->device);
}
int vfio_register_group_dev(struct vfio_device *device);