Commit 3c28a761 authored by Yi Liu's avatar Yi Liu Committed by Alex Williamson
Browse files

vfio: Add struct device to vfio_device 



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: default avatarJason Gunthorpe <jgg@nvidia.com>
Signed-off-by: default avatarYi Liu <yi.l.liu@intel.com>
Signed-off-by: default avatarKevin Tian <kevin.tian@intel.com>
Reviewed-by: default avatarJason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20220921104401.38898-16-kevin.tian@intel.com


Signed-off-by: default avatarAlex Williamson <alex.williamson@redhat.com>
parent 4a725b8d

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

0 → 100644
+8 −0
Original line number Diff line number Diff line 
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.

MAINTAINERS

+1 −0
Original line number Diff line number Diff line
@@ -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

drivers/vfio/vfio_main.c

+53 −11
Original line number Diff line number Diff line
@@ -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);

include/linux/vfio.h

+3 −3
Original line number Diff line number Diff line
@@ -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);