diff mbox series

[v4,15/15] vfio: Add struct device to vfio_device

Message ID 20220921104401.38898-16-kevin.tian@intel.com (mailing list archive)
State New, archived
Headers show
Series Tidy up vfio_device life cycle | expand

Commit Message

Tian, Kevin Sept. 21, 2022, 10:44 a.m. UTC
From: Yi Liu <yi.l.liu@intel.com>

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>
---
 .../ABI/testing/sysfs-devices-vfio-dev        |  8 +++
 MAINTAINERS                                   |  1 +
 drivers/vfio/vfio_main.c                      | 64 +++++++++++++++----
 include/linux/vfio.h                          |  6 +-
 4 files changed, 65 insertions(+), 14 deletions(-)
 create mode 100644 Documentation/ABI/testing/sysfs-devices-vfio-dev

Comments

Alex Williamson Sept. 29, 2022, 4:55 p.m. UTC | #1
Hi Kevin,

This introduced the regression discovered here:

https://lore.kernel.org/all/20220928125650.0a2ea297.alex.williamson@redhat.com/

Seems we're not releasing the resources when removing an mdev.  This is
a regression, so it needs to be fixed or reverted before the merge
window.  Thanks,

Alex

On Wed, 21 Sep 2022 18:44:01 +0800
Kevin Tian <kevin.tian@intel.com> wrote:

> From: Yi Liu <yi.l.liu@intel.com>
> 
> 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>
> ---
>  .../ABI/testing/sysfs-devices-vfio-dev        |  8 +++
>  MAINTAINERS                                   |  1 +
>  drivers/vfio/vfio_main.c                      | 64 +++++++++++++++----
>  include/linux/vfio.h                          |  6 +-
>  4 files changed, 65 insertions(+), 14 deletions(-)
>  create mode 100644 Documentation/ABI/testing/sysfs-devices-vfio-dev
> 
> diff --git a/Documentation/ABI/testing/sysfs-devices-vfio-dev b/Documentation/ABI/testing/sysfs-devices-vfio-dev
> new file mode 100644
> index 000000000000..e21424fd9666
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-devices-vfio-dev
> @@ -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.
> diff --git a/MAINTAINERS b/MAINTAINERS
> index d30f26e07cd3..02c8f11b1c17 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -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
> diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c
> index c27449613a1d..f9d10dbcf3e6 100644
> --- a/drivers/vfio/vfio_main.c
> +++ b/drivers/vfio/vfio_main.c
> @@ -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);
> diff --git a/include/linux/vfio.h b/include/linux/vfio.h
> index 3cf857b1eec7..ee399a768070 100644
> --- a/include/linux/vfio.h
> +++ b/include/linux/vfio.h
> @@ -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);
Alex Williamson Sept. 29, 2022, 6:24 p.m. UTC | #2
On Thu, 29 Sep 2022 14:49:56 -0300
Jason Gunthorpe <jgg@ziepe.ca> wrote:

> On Thu, Sep 29, 2022 at 10:55:19AM -0600, Alex Williamson wrote:
> > Hi Kevin,
> > 
> > This introduced the regression discovered here:
> > 
> > https://lore.kernel.org/all/20220928125650.0a2ea297.alex.williamson@redhat.com/
> > 
> > Seems we're not releasing the resources when removing an mdev.  This is
> > a regression, so it needs to be fixed or reverted before the merge
> > window.  Thanks,  
> 
> My guess at the fix for this:
> 
> https://lore.kernel.org/r/0-v1-013609965fe8+9d-vfio_gvt_unregister_jgg@nvidia.com

Indeed this seems to work  I'll look for acks and further reviews from
Intel folks. Thanks!

Alex
Tian, Kevin Sept. 30, 2022, 2:03 a.m. UTC | #3
> From: Alex Williamson <alex.williamson@redhat.com>
> Sent: Friday, September 30, 2022 2:24 AM
> 
> On Thu, 29 Sep 2022 14:49:56 -0300
> Jason Gunthorpe <jgg@ziepe.ca> wrote:
> 
> > On Thu, Sep 29, 2022 at 10:55:19AM -0600, Alex Williamson wrote:
> > > Hi Kevin,
> > >
> > > This introduced the regression discovered here:
> > >
> > >
> https://lore.kernel.org/all/20220928125650.0a2ea297.alex.williamson@redh
> at.com/
> > >
> > > Seems we're not releasing the resources when removing an mdev.  This is
> > > a regression, so it needs to be fixed or reverted before the merge
> > > window.  Thanks,
> >
> > My guess at the fix for this:
> >
> > https://lore.kernel.org/r/0-v1-013609965fe8+9d-
> vfio_gvt_unregister_jgg@nvidia.com
> 
> Indeed this seems to work  I'll look for acks and further reviews from
> Intel folks. Thanks!
> 

Thanks Jason for baking a quick fix! I've acked it.
diff mbox series

Patch

diff --git a/Documentation/ABI/testing/sysfs-devices-vfio-dev b/Documentation/ABI/testing/sysfs-devices-vfio-dev
new file mode 100644
index 000000000000..e21424fd9666
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-devices-vfio-dev
@@ -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.
diff --git a/MAINTAINERS b/MAINTAINERS
index d30f26e07cd3..02c8f11b1c17 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -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
diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c
index c27449613a1d..f9d10dbcf3e6 100644
--- a/drivers/vfio/vfio_main.c
+++ b/drivers/vfio/vfio_main.c
@@ -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);
diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index 3cf857b1eec7..ee399a768070 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -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);