[1/6] mdev: class id support
diff mbox series

Message ID 20190923130331.29324-2-jasowang@redhat.com
State Superseded
Headers show
Series
  • mdev based hardware virtio offloading support
Related show

Commit Message

Jason Wang Sept. 23, 2019, 1:03 p.m. UTC
Mdev bus only supports vfio driver right now, so it doesn't implement
match method. But in the future, we may add drivers other than vfio,
one example is virtio-mdev[1] driver. This means we need to add device
class id support in bus match method to pair the mdev device and mdev
driver correctly.

So this patch adds id_table to mdev_driver and class_id for mdev
parent with the match method for mdev bus.

Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 Documentation/driver-api/vfio-mediated-device.rst |  7 +++++--
 drivers/gpu/drm/i915/gvt/kvmgt.c                  |  2 +-
 drivers/s390/cio/vfio_ccw_ops.c                   |  2 +-
 drivers/s390/crypto/vfio_ap_ops.c                 |  3 ++-
 drivers/vfio/mdev/mdev_core.c                     | 14 ++++++++++++--
 drivers/vfio/mdev/mdev_driver.c                   | 14 ++++++++++++++
 drivers/vfio/mdev/mdev_private.h                  |  1 +
 drivers/vfio/mdev/vfio_mdev.c                     |  6 ++++++
 include/linux/mdev.h                              |  7 ++++++-
 include/linux/mod_devicetable.h                   |  8 ++++++++
 samples/vfio-mdev/mbochs.c                        |  2 +-
 samples/vfio-mdev/mdpy.c                          |  2 +-
 samples/vfio-mdev/mtty.c                          |  2 +-
 13 files changed, 59 insertions(+), 11 deletions(-)

Comments

Alex Williamson Sept. 23, 2019, 4:05 p.m. UTC | #1
On Mon, 23 Sep 2019 21:03:26 +0800
Jason Wang <jasowang@redhat.com> wrote:

> Mdev bus only supports vfio driver right now, so it doesn't implement
> match method. But in the future, we may add drivers other than vfio,
> one example is virtio-mdev[1] driver. This means we need to add device
> class id support in bus match method to pair the mdev device and mdev
> driver correctly.
> 
> So this patch adds id_table to mdev_driver and class_id for mdev
> parent with the match method for mdev bus.
> 
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
>  Documentation/driver-api/vfio-mediated-device.rst |  7 +++++--
>  drivers/gpu/drm/i915/gvt/kvmgt.c                  |  2 +-
>  drivers/s390/cio/vfio_ccw_ops.c                   |  2 +-
>  drivers/s390/crypto/vfio_ap_ops.c                 |  3 ++-
>  drivers/vfio/mdev/mdev_core.c                     | 14 ++++++++++++--
>  drivers/vfio/mdev/mdev_driver.c                   | 14 ++++++++++++++
>  drivers/vfio/mdev/mdev_private.h                  |  1 +
>  drivers/vfio/mdev/vfio_mdev.c                     |  6 ++++++
>  include/linux/mdev.h                              |  7 ++++++-
>  include/linux/mod_devicetable.h                   |  8 ++++++++
>  samples/vfio-mdev/mbochs.c                        |  2 +-
>  samples/vfio-mdev/mdpy.c                          |  2 +-
>  samples/vfio-mdev/mtty.c                          |  2 +-
>  13 files changed, 59 insertions(+), 11 deletions(-)
> 
> diff --git a/Documentation/driver-api/vfio-mediated-device.rst b/Documentation/driver-api/vfio-mediated-device.rst
> index 25eb7d5b834b..0e052072e1d8 100644
> --- a/Documentation/driver-api/vfio-mediated-device.rst
> +++ b/Documentation/driver-api/vfio-mediated-device.rst
> @@ -102,12 +102,14 @@ structure to represent a mediated device's driver::
>        * @probe: called when new device created
>        * @remove: called when device removed
>        * @driver: device driver structure
> +      * @id_table: the ids serviced by this driver.
>        */
>       struct mdev_driver {
>  	     const char *name;
>  	     int  (*probe)  (struct device *dev);
>  	     void (*remove) (struct device *dev);
>  	     struct device_driver    driver;
> +	     const struct mdev_class_id *id_table;
>       };
>  
>  A mediated bus driver for mdev should use this structure in the function calls
> @@ -116,7 +118,7 @@ to register and unregister itself with the core driver:
>  * Register::
>  
>      extern int  mdev_register_driver(struct mdev_driver *drv,
> -				   struct module *owner);
> +                                     struct module *owner);
>  
>  * Unregister::
>  
> @@ -163,7 +165,8 @@ A driver should use the mdev_parent_ops structure in the function call to
>  register itself with the mdev core driver::
>  
>  	extern int  mdev_register_device(struct device *dev,
> -	                                 const struct mdev_parent_ops *ops);
> +	                                 const struct mdev_parent_ops *ops,
> +	                                 u8 class_id);
>  
>  However, the mdev_parent_ops structure is not required in the function call
>  that a driver should use to unregister itself with the mdev core driver::
> diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
> index 23aa3e50cbf8..19d51a35f019 100644
> --- a/drivers/gpu/drm/i915/gvt/kvmgt.c
> +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
> @@ -1625,7 +1625,7 @@ static int kvmgt_host_init(struct device *dev, void *gvt, const void *ops)
>  		return -EFAULT;
>  	intel_vgpu_ops.supported_type_groups = kvm_vgpu_type_groups;
>  
> -	return mdev_register_device(dev, &intel_vgpu_ops);
> +	return mdev_register_vfio_device(dev, &intel_vgpu_ops);
>  }
>  
>  static void kvmgt_host_exit(struct device *dev)
> diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
> index f0d71ab77c50..246ff0f80944 100644
> --- a/drivers/s390/cio/vfio_ccw_ops.c
> +++ b/drivers/s390/cio/vfio_ccw_ops.c
> @@ -588,7 +588,7 @@ static const struct mdev_parent_ops vfio_ccw_mdev_ops = {
>  
>  int vfio_ccw_mdev_reg(struct subchannel *sch)
>  {
> -	return mdev_register_device(&sch->dev, &vfio_ccw_mdev_ops);
> +	return mdev_register_vfio_device(&sch->dev, &vfio_ccw_mdev_ops);
>  }
>  
>  void vfio_ccw_mdev_unreg(struct subchannel *sch)
> diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
> index 5c0f53c6dde7..7487fc39d2c5 100644
> --- a/drivers/s390/crypto/vfio_ap_ops.c
> +++ b/drivers/s390/crypto/vfio_ap_ops.c
> @@ -1295,7 +1295,8 @@ int vfio_ap_mdev_register(void)
>  {
>  	atomic_set(&matrix_dev->available_instances, MAX_ZDEV_ENTRIES_EXT);
>  
> -	return mdev_register_device(&matrix_dev->device, &vfio_ap_matrix_ops);
> +	return mdev_register_vfio_device(&matrix_dev->device,
> +					 &vfio_ap_matrix_ops);
>  }
>  
>  void vfio_ap_mdev_unregister(void)
> diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c
> index b558d4cfd082..a02c256a3514 100644
> --- a/drivers/vfio/mdev/mdev_core.c
> +++ b/drivers/vfio/mdev/mdev_core.c
> @@ -135,11 +135,14 @@ static int mdev_device_remove_cb(struct device *dev, void *data)
>   * mdev_register_device : Register a device
>   * @dev: device structure representing parent device.
>   * @ops: Parent device operation structure to be registered.
> + * @id: device id.
>   *
>   * Add device to list of registered parent devices.
>   * Returns a negative value on error, otherwise 0.
>   */
> -int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops)
> +int mdev_register_device(struct device *dev,
> +			 const struct mdev_parent_ops *ops,
> +			 u8 class_id)
>  {
>  	int ret;
>  	struct mdev_parent *parent;
> @@ -175,6 +178,7 @@ int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops)
>  
>  	parent->dev = dev;
>  	parent->ops = ops;
> +	parent->class_id = class_id;
>  

I don't think we want to tie the class_id to the parent.  mdev parent
devices can create various types of devices, some might be virtio, some
might be vfio.  I think the cover letter even suggests that's a
direction these virtio devices might be headed.  It seems the class
should be on the resulting device itself.  That also suggests that at
the parent we cannot have a single device_ops, the ops used will depend
on the type of device created.  Perhaps that means we need vfio_ops
alongside virtio_ops, rather than a common device_ops.  Thanks,

Alex


>  	if (!mdev_bus_compat_class) {
>  		mdev_bus_compat_class = class_compat_register("mdev_bus");
> @@ -208,7 +212,13 @@ int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops)
>  		put_device(dev);
>  	return ret;
>  }
> -EXPORT_SYMBOL(mdev_register_device);
> +
> +int mdev_register_vfio_device(struct device *dev,
> +			      const struct mdev_parent_ops *ops)
> +{
> +	return mdev_register_device(dev, ops, MDEV_ID_VFIO);
> +}
> +EXPORT_SYMBOL(mdev_register_vfio_device);
>  
>  /*
>   * mdev_unregister_device : Unregister a parent device
> diff --git a/drivers/vfio/mdev/mdev_driver.c b/drivers/vfio/mdev/mdev_driver.c
> index 0d3223aee20b..b70bbebc9dd3 100644
> --- a/drivers/vfio/mdev/mdev_driver.c
> +++ b/drivers/vfio/mdev/mdev_driver.c
> @@ -69,8 +69,22 @@ static int mdev_remove(struct device *dev)
>  	return 0;
>  }
>  
> +static int mdev_match(struct device *dev, struct device_driver *drv)
> +{
> +	unsigned int i;
> +	struct mdev_device *mdev = to_mdev_device(dev);
> +	struct mdev_driver *mdrv = to_mdev_driver(drv);
> +	const struct mdev_class_id *ids = mdrv->id_table;
> +
> +	for (i = 0; ids[i].id; i++)
> +		if (ids[i].id == mdev->parent->class_id)
> +			return 1;
> +	return 0;
> +}
> +
>  struct bus_type mdev_bus_type = {
>  	.name		= "mdev",
> +	.match		= mdev_match,
>  	.probe		= mdev_probe,
>  	.remove		= mdev_remove,
>  };
> diff --git a/drivers/vfio/mdev/mdev_private.h b/drivers/vfio/mdev/mdev_private.h
> index 7d922950caaf..e58b07c866b1 100644
> --- a/drivers/vfio/mdev/mdev_private.h
> +++ b/drivers/vfio/mdev/mdev_private.h
> @@ -22,6 +22,7 @@ struct mdev_parent {
>  	struct list_head type_list;
>  	/* Synchronize device creation/removal with parent unregistration */
>  	struct rw_semaphore unreg_sem;
> +	u8 class_id;
>  };
>  
>  struct mdev_device {
> diff --git a/drivers/vfio/mdev/vfio_mdev.c b/drivers/vfio/mdev/vfio_mdev.c
> index 30964a4e0a28..fd2a4d9a3f26 100644
> --- a/drivers/vfio/mdev/vfio_mdev.c
> +++ b/drivers/vfio/mdev/vfio_mdev.c
> @@ -120,10 +120,16 @@ static void vfio_mdev_remove(struct device *dev)
>  	vfio_del_group_dev(dev);
>  }
>  
> +static struct mdev_class_id id_table[] = {
> +	{ MDEV_ID_VFIO },
> +	{ 0 },
> +};
> +
>  static struct mdev_driver vfio_mdev_driver = {
>  	.name	= "vfio_mdev",
>  	.probe	= vfio_mdev_probe,
>  	.remove	= vfio_mdev_remove,
> +	.id_table = id_table,
>  };
>  
>  static int __init vfio_mdev_init(void)
> diff --git a/include/linux/mdev.h b/include/linux/mdev.h
> index 0ce30ca78db0..3ebae310f599 100644
> --- a/include/linux/mdev.h
> +++ b/include/linux/mdev.h
> @@ -118,6 +118,7 @@ struct mdev_type_attribute mdev_type_attr_##_name =		\
>   * @probe: called when new device created
>   * @remove: called when device removed
>   * @driver: device driver structure
> + * @id_table: the ids serviced by this driver.
>   *
>   **/
>  struct mdev_driver {
> @@ -125,6 +126,7 @@ struct mdev_driver {
>  	int  (*probe)(struct device *dev);
>  	void (*remove)(struct device *dev);
>  	struct device_driver driver;
> +	const struct mdev_class_id *id_table;
>  };
>  
>  #define to_mdev_driver(drv)	container_of(drv, struct mdev_driver, driver)
> @@ -135,7 +137,8 @@ const guid_t *mdev_uuid(struct mdev_device *mdev);
>  
>  extern struct bus_type mdev_bus_type;
>  
> -int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops);
> +int mdev_register_vfio_device(struct device *dev,
> +			      const struct mdev_parent_ops *ops);
>  void mdev_unregister_device(struct device *dev);
>  
>  int mdev_register_driver(struct mdev_driver *drv, struct module *owner);
> @@ -145,4 +148,6 @@ struct device *mdev_parent_dev(struct mdev_device *mdev);
>  struct device *mdev_dev(struct mdev_device *mdev);
>  struct mdev_device *mdev_from_dev(struct device *dev);
>  
> +#define MDEV_ID_VFIO 1 /* VFIO device */
> +
>  #endif /* MDEV_H */
> diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
> index 5714fd35a83c..f32c6e44fb1a 100644
> --- a/include/linux/mod_devicetable.h
> +++ b/include/linux/mod_devicetable.h
> @@ -821,4 +821,12 @@ struct wmi_device_id {
>  	const void *context;
>  };
>  
> +/**
> + * struct mdev_class_id - MDEV device class identifier
> + * @id: Used to identify a specific class of device, e.g vfio-mdev device.
> + */
> +struct mdev_class_id {
> +	__u16 id;
> +};
> +
>  #endif /* LINUX_MOD_DEVICETABLE_H */
> diff --git a/samples/vfio-mdev/mbochs.c b/samples/vfio-mdev/mbochs.c
> index ac5c8c17b1ff..71a4469be85d 100644
> --- a/samples/vfio-mdev/mbochs.c
> +++ b/samples/vfio-mdev/mbochs.c
> @@ -1468,7 +1468,7 @@ static int __init mbochs_dev_init(void)
>  	if (ret)
>  		goto failed2;
>  
> -	ret = mdev_register_device(&mbochs_dev, &mdev_fops);
> +	ret = mdev_register_vfio_device(&mbochs_dev, &mdev_fops);
>  	if (ret)
>  		goto failed3;
>  
> diff --git a/samples/vfio-mdev/mdpy.c b/samples/vfio-mdev/mdpy.c
> index cc86bf6566e4..d3029dd27d91 100644
> --- a/samples/vfio-mdev/mdpy.c
> +++ b/samples/vfio-mdev/mdpy.c
> @@ -775,7 +775,7 @@ static int __init mdpy_dev_init(void)
>  	if (ret)
>  		goto failed2;
>  
> -	ret = mdev_register_device(&mdpy_dev, &mdev_fops);
> +	ret = mdev_register_vfio_device(&mdpy_dev, &mdev_fops);
>  	if (ret)
>  		goto failed3;
>  
> diff --git a/samples/vfio-mdev/mtty.c b/samples/vfio-mdev/mtty.c
> index 92e770a06ea2..744c88a6b22c 100644
> --- a/samples/vfio-mdev/mtty.c
> +++ b/samples/vfio-mdev/mtty.c
> @@ -1468,7 +1468,7 @@ static int __init mtty_dev_init(void)
>  	if (ret)
>  		goto failed2;
>  
> -	ret = mdev_register_device(&mtty_dev.dev, &mdev_fops);
> +	ret = mdev_register_vfio_device(&mtty_dev.dev, &mdev_fops);
>  	if (ret)
>  		goto failed3;
>
Parav Pandit Sept. 23, 2019, 8:58 p.m. UTC | #2
Hi Jason,

> -----Original Message-----
> From: Jason Wang <jasowang@redhat.com>
> Sent: Monday, September 23, 2019 8:03 AM
> To: kvm@vger.kernel.org; linux-s390@vger.kernel.org; linux-
> kernel@vger.kernel.org; dri-devel@lists.freedesktop.org; intel-
> gfx@lists.freedesktop.org; intel-gvt-dev@lists.freedesktop.org;
> kwankhede@nvidia.com; alex.williamson@redhat.com; mst@redhat.com;
> tiwei.bie@intel.com
> Cc: virtualization@lists.linux-foundation.org; netdev@vger.kernel.org;
> cohuck@redhat.com; maxime.coquelin@redhat.com;
> cunming.liang@intel.com; zhihong.wang@intel.com;
> rob.miller@broadcom.com; xiao.w.wang@intel.com;
> haotian.wang@sifive.com; zhenyuw@linux.intel.com; zhi.a.wang@intel.com;
> jani.nikula@linux.intel.com; joonas.lahtinen@linux.intel.com;
> rodrigo.vivi@intel.com; airlied@linux.ie; daniel@ffwll.ch;
> farman@linux.ibm.com; pasic@linux.ibm.com; sebott@linux.ibm.com;
> oberpar@linux.ibm.com; heiko.carstens@de.ibm.com; gor@linux.ibm.com;
> borntraeger@de.ibm.com; akrowiak@linux.ibm.com; freude@linux.ibm.com;
> lingshan.zhu@intel.com; Ido Shamay <idos@mellanox.com>;
> eperezma@redhat.com; lulu@redhat.com; Parav Pandit
> <parav@mellanox.com>; Jason Wang <jasowang@redhat.com>
> Subject: [PATCH 1/6] mdev: class id support
> 
> Mdev bus only supports vfio driver right now, so it doesn't implement match
> method. But in the future, we may add drivers other than vfio, one example is
> virtio-mdev[1] driver. This means we need to add device class id support in bus
> match method to pair the mdev device and mdev driver correctly.
> 
> So this patch adds id_table to mdev_driver and class_id for mdev parent with
> the match method for mdev bus.
> 
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
>  Documentation/driver-api/vfio-mediated-device.rst |  7 +++++--
>  drivers/gpu/drm/i915/gvt/kvmgt.c                  |  2 +-
>  drivers/s390/cio/vfio_ccw_ops.c                   |  2 +-
>  drivers/s390/crypto/vfio_ap_ops.c                 |  3 ++-
>  drivers/vfio/mdev/mdev_core.c                     | 14 ++++++++++++--
>  drivers/vfio/mdev/mdev_driver.c                   | 14 ++++++++++++++
>  drivers/vfio/mdev/mdev_private.h                  |  1 +
>  drivers/vfio/mdev/vfio_mdev.c                     |  6 ++++++
>  include/linux/mdev.h                              |  7 ++++++-
>  include/linux/mod_devicetable.h                   |  8 ++++++++
>  samples/vfio-mdev/mbochs.c                        |  2 +-
>  samples/vfio-mdev/mdpy.c                          |  2 +-
>  samples/vfio-mdev/mtty.c                          |  2 +-
>  13 files changed, 59 insertions(+), 11 deletions(-)
> 
> diff --git a/Documentation/driver-api/vfio-mediated-device.rst
> b/Documentation/driver-api/vfio-mediated-device.rst
> index 25eb7d5b834b..0e052072e1d8 100644
> --- a/Documentation/driver-api/vfio-mediated-device.rst
> +++ b/Documentation/driver-api/vfio-mediated-device.rst
> @@ -102,12 +102,14 @@ structure to represent a mediated device's driver::
>        * @probe: called when new device created
>        * @remove: called when device removed
>        * @driver: device driver structure
> +      * @id_table: the ids serviced by this driver.
No full stop at the end.

>        */
>       struct mdev_driver {
>  	     const char *name;
>  	     int  (*probe)  (struct device *dev);
>  	     void (*remove) (struct device *dev);
>  	     struct device_driver    driver;
> +	     const struct mdev_class_id *id_table;
>       };
> 
>  A mediated bus driver for mdev should use this structure in the function calls
> @@ -116,7 +118,7 @@ to register and unregister itself with the core driver:
>  * Register::
> 
>      extern int  mdev_register_driver(struct mdev_driver *drv,
> -				   struct module *owner);
> +                                     struct module *owner);
> 
Unrelated change in this patch.

>  * Unregister::
> 
> @@ -163,7 +165,8 @@ A driver should use the mdev_parent_ops structure in
> the function call to  register itself with the mdev core driver::
> 
>  	extern int  mdev_register_device(struct device *dev,
> -	                                 const struct mdev_parent_ops *ops);
> +	                                 const struct mdev_parent_ops *ops,
> +	                                 u8 class_id);
> 
Cover letter from Change-V2 says that it class_id changed from " use u16 instead u8 for class id"
But it is still u8 here?

>  However, the mdev_parent_ops structure is not required in the function call
> that a driver should use to unregister itself with the mdev core driver::
> diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c
> b/drivers/gpu/drm/i915/gvt/kvmgt.c
> index 23aa3e50cbf8..19d51a35f019 100644
> --- a/drivers/gpu/drm/i915/gvt/kvmgt.c
> +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
> @@ -1625,7 +1625,7 @@ static int kvmgt_host_init(struct device *dev, void
> *gvt, const void *ops)
>  		return -EFAULT;
>  	intel_vgpu_ops.supported_type_groups = kvm_vgpu_type_groups;
> 
> -	return mdev_register_device(dev, &intel_vgpu_ops);
> +	return mdev_register_vfio_device(dev, &intel_vgpu_ops);
>  }
> 
>  static void kvmgt_host_exit(struct device *dev) diff --git
> a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c index
> f0d71ab77c50..246ff0f80944 100644
> --- a/drivers/s390/cio/vfio_ccw_ops.c
> +++ b/drivers/s390/cio/vfio_ccw_ops.c
> @@ -588,7 +588,7 @@ static const struct mdev_parent_ops
> vfio_ccw_mdev_ops = {
> 
>  int vfio_ccw_mdev_reg(struct subchannel *sch)  {
> -	return mdev_register_device(&sch->dev, &vfio_ccw_mdev_ops);
> +	return mdev_register_vfio_device(&sch->dev, &vfio_ccw_mdev_ops);
>  }
> 
>  void vfio_ccw_mdev_unreg(struct subchannel *sch) diff --git
> a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
> index 5c0f53c6dde7..7487fc39d2c5 100644
> --- a/drivers/s390/crypto/vfio_ap_ops.c
> +++ b/drivers/s390/crypto/vfio_ap_ops.c
> @@ -1295,7 +1295,8 @@ int vfio_ap_mdev_register(void)  {
>  	atomic_set(&matrix_dev->available_instances,
> MAX_ZDEV_ENTRIES_EXT);
> 
> -	return mdev_register_device(&matrix_dev->device,
> &vfio_ap_matrix_ops);
> +	return mdev_register_vfio_device(&matrix_dev->device,
> +					 &vfio_ap_matrix_ops);
>  }
> 
>  void vfio_ap_mdev_unregister(void)
> diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c
> index b558d4cfd082..a02c256a3514 100644
> --- a/drivers/vfio/mdev/mdev_core.c
> +++ b/drivers/vfio/mdev/mdev_core.c
> @@ -135,11 +135,14 @@ static int mdev_device_remove_cb(struct device
> *dev, void *data)
>   * mdev_register_device : Register a device
>   * @dev: device structure representing parent device.
>   * @ops: Parent device operation structure to be registered.
> + * @id: device id.
>   *
It device id here, but in below its class_id. Please make them uniform.

>   * Add device to list of registered parent devices.
>   * Returns a negative value on error, otherwise 0.
>   */
> -int mdev_register_device(struct device *dev, const struct mdev_parent_ops
> *ops)
> +int mdev_register_device(struct device *dev,
> +			 const struct mdev_parent_ops *ops,
> +			 u8 class_id)
>  {
u16 class_id?

>  	int ret;
>  	struct mdev_parent *parent;
> @@ -175,6 +178,7 @@ int mdev_register_device(struct device *dev, const
> struct mdev_parent_ops *ops)
> 
>  	parent->dev = dev;
>  	parent->ops = ops;
> +	parent->class_id = class_id;
> 
>  	if (!mdev_bus_compat_class) {
>  		mdev_bus_compat_class =
> class_compat_register("mdev_bus");
> @@ -208,7 +212,13 @@ int mdev_register_device(struct device *dev, const
> struct mdev_parent_ops *ops)
>  		put_device(dev);
>  	return ret;
>  }
> -EXPORT_SYMBOL(mdev_register_device);
> +
> +int mdev_register_vfio_device(struct device *dev,
> +			      const struct mdev_parent_ops *ops) {
> +	return mdev_register_device(dev, ops, MDEV_ID_VFIO); }
> +EXPORT_SYMBOL(mdev_register_vfio_device);
> 
>  /*
>   * mdev_unregister_device : Unregister a parent device diff --git
> a/drivers/vfio/mdev/mdev_driver.c b/drivers/vfio/mdev/mdev_driver.c index
> 0d3223aee20b..b70bbebc9dd3 100644
> --- a/drivers/vfio/mdev/mdev_driver.c
> +++ b/drivers/vfio/mdev/mdev_driver.c
> @@ -69,8 +69,22 @@ static int mdev_remove(struct device *dev)
>  	return 0;
>  }
> 
> +static int mdev_match(struct device *dev, struct device_driver *drv) {
> +	unsigned int i;
> +	struct mdev_device *mdev = to_mdev_device(dev);
> +	struct mdev_driver *mdrv = to_mdev_driver(drv);
> +	const struct mdev_class_id *ids = mdrv->id_table;
> +
> +	for (i = 0; ids[i].id; i++)
> +		if (ids[i].id == mdev->parent->class_id)
> +			return 1;
> +	return 0;
> +}
> +
>  struct bus_type mdev_bus_type = {
>  	.name		= "mdev",
> +	.match		= mdev_match,
>  	.probe		= mdev_probe,
>  	.remove		= mdev_remove,
>  };
> diff --git a/drivers/vfio/mdev/mdev_private.h
> b/drivers/vfio/mdev/mdev_private.h
> index 7d922950caaf..e58b07c866b1 100644
> --- a/drivers/vfio/mdev/mdev_private.h
> +++ b/drivers/vfio/mdev/mdev_private.h
> @@ -22,6 +22,7 @@ struct mdev_parent {
>  	struct list_head type_list;
>  	/* Synchronize device creation/removal with parent unregistration */
>  	struct rw_semaphore unreg_sem;
> +	u8 class_id;
>  };
> 
>  struct mdev_device {
> diff --git a/drivers/vfio/mdev/vfio_mdev.c b/drivers/vfio/mdev/vfio_mdev.c
> index 30964a4e0a28..fd2a4d9a3f26 100644
> --- a/drivers/vfio/mdev/vfio_mdev.c
> +++ b/drivers/vfio/mdev/vfio_mdev.c
> @@ -120,10 +120,16 @@ static void vfio_mdev_remove(struct device *dev)
>  	vfio_del_group_dev(dev);
>  }
> 
> +static struct mdev_class_id id_table[] = {
> +	{ MDEV_ID_VFIO },
> +	{ 0 },
> +};
> +
>  static struct mdev_driver vfio_mdev_driver = {
>  	.name	= "vfio_mdev",
>  	.probe	= vfio_mdev_probe,
>  	.remove	= vfio_mdev_remove,
> +	.id_table = id_table,
>  };
> 
>  static int __init vfio_mdev_init(void)
> diff --git a/include/linux/mdev.h b/include/linux/mdev.h index
> 0ce30ca78db0..3ebae310f599 100644
> --- a/include/linux/mdev.h
> +++ b/include/linux/mdev.h
> @@ -118,6 +118,7 @@ struct mdev_type_attribute mdev_type_attr_##_name
> =		\
>   * @probe: called when new device created
>   * @remove: called when device removed
>   * @driver: device driver structure
> + * @id_table: the ids serviced by this driver.
>   *
>   **/
>  struct mdev_driver {
> @@ -125,6 +126,7 @@ struct mdev_driver {
>  	int  (*probe)(struct device *dev);
>  	void (*remove)(struct device *dev);
>  	struct device_driver driver;
> +	const struct mdev_class_id *id_table;
>  };
> 
>  #define to_mdev_driver(drv)	container_of(drv, struct mdev_driver, driver)
> @@ -135,7 +137,8 @@ const guid_t *mdev_uuid(struct mdev_device *mdev);
> 
>  extern struct bus_type mdev_bus_type;
> 
> -int mdev_register_device(struct device *dev, const struct mdev_parent_ops
> *ops);
> +int mdev_register_vfio_device(struct device *dev,
> +			      const struct mdev_parent_ops *ops);
>  void mdev_unregister_device(struct device *dev);
> 
>  int mdev_register_driver(struct mdev_driver *drv, struct module *owner);
> @@ -145,4 +148,6 @@ struct device *mdev_parent_dev(struct mdev_device
> *mdev);  struct device *mdev_dev(struct mdev_device *mdev);  struct
> mdev_device *mdev_from_dev(struct device *dev);
> 
> +#define MDEV_ID_VFIO 1 /* VFIO device */
> +
Instead of define, please put them as enum 

enum mdev_class/device_id {
	MDEV_ID_VFIO = 1,
	/* New entries must be added here */
};

>  #endif /* MDEV_H */
> diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
> index 5714fd35a83c..f32c6e44fb1a 100644
> --- a/include/linux/mod_devicetable.h
> +++ b/include/linux/mod_devicetable.h
> @@ -821,4 +821,12 @@ struct wmi_device_id {
>  	const void *context;
>  };
> 
> +/**
> + * struct mdev_class_id - MDEV device class identifier
> + * @id: Used to identify a specific class of device, e.g vfio-mdev device.
> + */
> +struct mdev_class_id {
> +	__u16 id;
> +};
This is u16 as I guess you wanted as opposed to u8 in other places in patch.

> +
>  #endif /* LINUX_MOD_DEVICETABLE_H */
> diff --git a/samples/vfio-mdev/mbochs.c b/samples/vfio-mdev/mbochs.c index
> ac5c8c17b1ff..71a4469be85d 100644
> --- a/samples/vfio-mdev/mbochs.c
> +++ b/samples/vfio-mdev/mbochs.c
> @@ -1468,7 +1468,7 @@ static int __init mbochs_dev_init(void)
>  	if (ret)
>  		goto failed2;
> 
> -	ret = mdev_register_device(&mbochs_dev, &mdev_fops);
> +	ret = mdev_register_vfio_device(&mbochs_dev, &mdev_fops);
>  	if (ret)
>  		goto failed3;
> 
> diff --git a/samples/vfio-mdev/mdpy.c b/samples/vfio-mdev/mdpy.c index
> cc86bf6566e4..d3029dd27d91 100644
> --- a/samples/vfio-mdev/mdpy.c
> +++ b/samples/vfio-mdev/mdpy.c
> @@ -775,7 +775,7 @@ static int __init mdpy_dev_init(void)
>  	if (ret)
>  		goto failed2;
> 
> -	ret = mdev_register_device(&mdpy_dev, &mdev_fops);
> +	ret = mdev_register_vfio_device(&mdpy_dev, &mdev_fops);
>  	if (ret)
>  		goto failed3;
> 
> diff --git a/samples/vfio-mdev/mtty.c b/samples/vfio-mdev/mtty.c index
> 92e770a06ea2..744c88a6b22c 100644
> --- a/samples/vfio-mdev/mtty.c
> +++ b/samples/vfio-mdev/mtty.c
> @@ -1468,7 +1468,7 @@ static int __init mtty_dev_init(void)
>  	if (ret)
>  		goto failed2;
> 
> -	ret = mdev_register_device(&mtty_dev.dev, &mdev_fops);
> +	ret = mdev_register_vfio_device(&mtty_dev.dev, &mdev_fops);
>  	if (ret)
>  		goto failed3;
> 
> --
> 2.19.1
Parav Pandit Sept. 23, 2019, 9:02 p.m. UTC | #3
Hi Jason,


> -----Original Message-----
> From: Jason Wang <jasowang@redhat.com>
> Sent: Monday, September 23, 2019 8:03 AM
> To: kvm@vger.kernel.org; linux-s390@vger.kernel.org; linux-
> kernel@vger.kernel.org; dri-devel@lists.freedesktop.org; intel-
> gfx@lists.freedesktop.org; intel-gvt-dev@lists.freedesktop.org;
> kwankhede@nvidia.com; alex.williamson@redhat.com; mst@redhat.com;
> tiwei.bie@intel.com
> Cc: virtualization@lists.linux-foundation.org; netdev@vger.kernel.org;
> cohuck@redhat.com; maxime.coquelin@redhat.com;
> cunming.liang@intel.com; zhihong.wang@intel.com;
> rob.miller@broadcom.com; xiao.w.wang@intel.com;
> haotian.wang@sifive.com; zhenyuw@linux.intel.com; zhi.a.wang@intel.com;
> jani.nikula@linux.intel.com; joonas.lahtinen@linux.intel.com;
> rodrigo.vivi@intel.com; airlied@linux.ie; daniel@ffwll.ch;
> farman@linux.ibm.com; pasic@linux.ibm.com; sebott@linux.ibm.com;
> oberpar@linux.ibm.com; heiko.carstens@de.ibm.com; gor@linux.ibm.com;
> borntraeger@de.ibm.com; akrowiak@linux.ibm.com; freude@linux.ibm.com;
> lingshan.zhu@intel.com; Ido Shamay <idos@mellanox.com>;
> eperezma@redhat.com; lulu@redhat.com; Parav Pandit
> <parav@mellanox.com>; Jason Wang <jasowang@redhat.com>
> Subject: [PATCH 1/6] mdev: class id support
> 
> Mdev bus only supports vfio driver right now, so it doesn't implement match
> method. But in the future, we may add drivers other than vfio, one example is
> virtio-mdev[1] driver. This means we need to add device class id support in bus
> match method to pair the mdev device and mdev driver correctly.
> 
> So this patch adds id_table to mdev_driver and class_id for mdev parent with
> the match method for mdev bus.
> 
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
>  Documentation/driver-api/vfio-mediated-device.rst |  7 +++++--
>  drivers/gpu/drm/i915/gvt/kvmgt.c                  |  2 +-
>  drivers/s390/cio/vfio_ccw_ops.c                   |  2 +-
>  drivers/s390/crypto/vfio_ap_ops.c                 |  3 ++-
>  drivers/vfio/mdev/mdev_core.c                     | 14 ++++++++++++--
>  drivers/vfio/mdev/mdev_driver.c                   | 14 ++++++++++++++
>  drivers/vfio/mdev/mdev_private.h                  |  1 +
>  drivers/vfio/mdev/vfio_mdev.c                     |  6 ++++++
>  include/linux/mdev.h                              |  7 ++++++-
>  include/linux/mod_devicetable.h                   |  8 ++++++++
>  samples/vfio-mdev/mbochs.c                        |  2 +-
>  samples/vfio-mdev/mdpy.c                          |  2 +-
>  samples/vfio-mdev/mtty.c                          |  2 +-
>  13 files changed, 59 insertions(+), 11 deletions(-)
> 
You additionally need modpost support for id table integration to modifo, modprobe and other tools.
A small patch similar to this one [1] is needed.
Please include in the series.

[1] https://lore.kernel.org/patchwork/patch/1046991/
Jason Wang Sept. 24, 2019, 10:11 a.m. UTC | #4
On 2019/9/24 上午12:05, Alex Williamson wrote:
> On Mon, 23 Sep 2019 21:03:26 +0800
> Jason Wang <jasowang@redhat.com> wrote:
>
>> Mdev bus only supports vfio driver right now, so it doesn't implement
>> match method. But in the future, we may add drivers other than vfio,
>> one example is virtio-mdev[1] driver. This means we need to add device
>> class id support in bus match method to pair the mdev device and mdev
>> driver correctly.
>>
>> So this patch adds id_table to mdev_driver and class_id for mdev
>> parent with the match method for mdev bus.
>>
>> Signed-off-by: Jason Wang <jasowang@redhat.com>
>> ---
>>  Documentation/driver-api/vfio-mediated-device.rst |  7 +++++--
>>  drivers/gpu/drm/i915/gvt/kvmgt.c                  |  2 +-
>>  drivers/s390/cio/vfio_ccw_ops.c                   |  2 +-
>>  drivers/s390/crypto/vfio_ap_ops.c                 |  3 ++-
>>  drivers/vfio/mdev/mdev_core.c                     | 14 ++++++++++++--
>>  drivers/vfio/mdev/mdev_driver.c                   | 14 ++++++++++++++
>>  drivers/vfio/mdev/mdev_private.h                  |  1 +
>>  drivers/vfio/mdev/vfio_mdev.c                     |  6 ++++++
>>  include/linux/mdev.h                              |  7 ++++++-
>>  include/linux/mod_devicetable.h                   |  8 ++++++++
>>  samples/vfio-mdev/mbochs.c                        |  2 +-
>>  samples/vfio-mdev/mdpy.c                          |  2 +-
>>  samples/vfio-mdev/mtty.c                          |  2 +-
>>  13 files changed, 59 insertions(+), 11 deletions(-)
>>
>> diff --git a/Documentation/driver-api/vfio-mediated-device.rst b/Documentation/driver-api/vfio-mediated-device.rst
>> index 25eb7d5b834b..0e052072e1d8 100644
>> --- a/Documentation/driver-api/vfio-mediated-device.rst
>> +++ b/Documentation/driver-api/vfio-mediated-device.rst
>> @@ -102,12 +102,14 @@ structure to represent a mediated device's driver::
>>        * @probe: called when new device created
>>        * @remove: called when device removed
>>        * @driver: device driver structure
>> +      * @id_table: the ids serviced by this driver.
>>        */
>>       struct mdev_driver {
>>  	     const char *name;
>>  	     int  (*probe)  (struct device *dev);
>>  	     void (*remove) (struct device *dev);
>>  	     struct device_driver    driver;
>> +	     const struct mdev_class_id *id_table;
>>       };
>>  
>>  A mediated bus driver for mdev should use this structure in the function calls
>> @@ -116,7 +118,7 @@ to register and unregister itself with the core driver:
>>  * Register::
>>  
>>      extern int  mdev_register_driver(struct mdev_driver *drv,
>> -				   struct module *owner);
>> +                                     struct module *owner);
>>  
>>  * Unregister::
>>  
>> @@ -163,7 +165,8 @@ A driver should use the mdev_parent_ops structure in the function call to
>>  register itself with the mdev core driver::
>>  
>>  	extern int  mdev_register_device(struct device *dev,
>> -	                                 const struct mdev_parent_ops *ops);
>> +	                                 const struct mdev_parent_ops *ops,
>> +	                                 u8 class_id);
>>  
>>  However, the mdev_parent_ops structure is not required in the function call
>>  that a driver should use to unregister itself with the mdev core driver::
>> diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
>> index 23aa3e50cbf8..19d51a35f019 100644
>> --- a/drivers/gpu/drm/i915/gvt/kvmgt.c
>> +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
>> @@ -1625,7 +1625,7 @@ static int kvmgt_host_init(struct device *dev, void *gvt, const void *ops)
>>  		return -EFAULT;
>>  	intel_vgpu_ops.supported_type_groups = kvm_vgpu_type_groups;
>>  
>> -	return mdev_register_device(dev, &intel_vgpu_ops);
>> +	return mdev_register_vfio_device(dev, &intel_vgpu_ops);
>>  }
>>  
>>  static void kvmgt_host_exit(struct device *dev)
>> diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
>> index f0d71ab77c50..246ff0f80944 100644
>> --- a/drivers/s390/cio/vfio_ccw_ops.c
>> +++ b/drivers/s390/cio/vfio_ccw_ops.c
>> @@ -588,7 +588,7 @@ static const struct mdev_parent_ops vfio_ccw_mdev_ops = {
>>  
>>  int vfio_ccw_mdev_reg(struct subchannel *sch)
>>  {
>> -	return mdev_register_device(&sch->dev, &vfio_ccw_mdev_ops);
>> +	return mdev_register_vfio_device(&sch->dev, &vfio_ccw_mdev_ops);
>>  }
>>  
>>  void vfio_ccw_mdev_unreg(struct subchannel *sch)
>> diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
>> index 5c0f53c6dde7..7487fc39d2c5 100644
>> --- a/drivers/s390/crypto/vfio_ap_ops.c
>> +++ b/drivers/s390/crypto/vfio_ap_ops.c
>> @@ -1295,7 +1295,8 @@ int vfio_ap_mdev_register(void)
>>  {
>>  	atomic_set(&matrix_dev->available_instances, MAX_ZDEV_ENTRIES_EXT);
>>  
>> -	return mdev_register_device(&matrix_dev->device, &vfio_ap_matrix_ops);
>> +	return mdev_register_vfio_device(&matrix_dev->device,
>> +					 &vfio_ap_matrix_ops);
>>  }
>>  
>>  void vfio_ap_mdev_unregister(void)
>> diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c
>> index b558d4cfd082..a02c256a3514 100644
>> --- a/drivers/vfio/mdev/mdev_core.c
>> +++ b/drivers/vfio/mdev/mdev_core.c
>> @@ -135,11 +135,14 @@ static int mdev_device_remove_cb(struct device *dev, void *data)
>>   * mdev_register_device : Register a device
>>   * @dev: device structure representing parent device.
>>   * @ops: Parent device operation structure to be registered.
>> + * @id: device id.
>>   *
>>   * Add device to list of registered parent devices.
>>   * Returns a negative value on error, otherwise 0.
>>   */
>> -int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops)
>> +int mdev_register_device(struct device *dev,
>> +			 const struct mdev_parent_ops *ops,
>> +			 u8 class_id)
>>  {
>>  	int ret;
>>  	struct mdev_parent *parent;
>> @@ -175,6 +178,7 @@ int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops)
>>  
>>  	parent->dev = dev;
>>  	parent->ops = ops;
>> +	parent->class_id = class_id;
>>  
> I don't think we want to tie the class_id to the parent.  mdev parent
> devices can create various types of devices, some might be virtio, some
> might be vfio.  I think the cover letter even suggests that's a
> direction these virtio devices might be headed.  It seems the class
> should be on the resulting device itself.  That also suggests that at
> the parent we cannot have a single device_ops, the ops used will depend
> on the type of device created.  Perhaps that means we need vfio_ops
> alongside virtio_ops, rather than a common device_ops.  Thanks,
>
> Alex
>

Yes, will do it in V2.

Thanks
Jason Wang Sept. 24, 2019, 11:20 a.m. UTC | #5
On 2019/9/24 上午4:58, Parav Pandit wrote:
> Hi Jason,
>
>> -----Original Message-----
>> From: Jason Wang <jasowang@redhat.com>
>> Sent: Monday, September 23, 2019 8:03 AM
>> To: kvm@vger.kernel.org; linux-s390@vger.kernel.org; linux-
>> kernel@vger.kernel.org; dri-devel@lists.freedesktop.org; intel-
>> gfx@lists.freedesktop.org; intel-gvt-dev@lists.freedesktop.org;
>> kwankhede@nvidia.com; alex.williamson@redhat.com; mst@redhat.com;
>> tiwei.bie@intel.com
>> Cc: virtualization@lists.linux-foundation.org; netdev@vger.kernel.org;
>> cohuck@redhat.com; maxime.coquelin@redhat.com;
>> cunming.liang@intel.com; zhihong.wang@intel.com;
>> rob.miller@broadcom.com; xiao.w.wang@intel.com;
>> haotian.wang@sifive.com; zhenyuw@linux.intel.com; zhi.a.wang@intel.com;
>> jani.nikula@linux.intel.com; joonas.lahtinen@linux.intel.com;
>> rodrigo.vivi@intel.com; airlied@linux.ie; daniel@ffwll.ch;
>> farman@linux.ibm.com; pasic@linux.ibm.com; sebott@linux.ibm.com;
>> oberpar@linux.ibm.com; heiko.carstens@de.ibm.com; gor@linux.ibm.com;
>> borntraeger@de.ibm.com; akrowiak@linux.ibm.com; freude@linux.ibm.com;
>> lingshan.zhu@intel.com; Ido Shamay <idos@mellanox.com>;
>> eperezma@redhat.com; lulu@redhat.com; Parav Pandit
>> <parav@mellanox.com>; Jason Wang <jasowang@redhat.com>
>> Subject: [PATCH 1/6] mdev: class id support
>>
>> Mdev bus only supports vfio driver right now, so it doesn't implement match
>> method. But in the future, we may add drivers other than vfio, one example is
>> virtio-mdev[1] driver. This means we need to add device class id support in bus
>> match method to pair the mdev device and mdev driver correctly.
>>
>> So this patch adds id_table to mdev_driver and class_id for mdev parent with
>> the match method for mdev bus.
>>
>> Signed-off-by: Jason Wang <jasowang@redhat.com>
>> ---
>>  Documentation/driver-api/vfio-mediated-device.rst |  7 +++++--
>>  drivers/gpu/drm/i915/gvt/kvmgt.c                  |  2 +-
>>  drivers/s390/cio/vfio_ccw_ops.c                   |  2 +-
>>  drivers/s390/crypto/vfio_ap_ops.c                 |  3 ++-
>>  drivers/vfio/mdev/mdev_core.c                     | 14 ++++++++++++--
>>  drivers/vfio/mdev/mdev_driver.c                   | 14 ++++++++++++++
>>  drivers/vfio/mdev/mdev_private.h                  |  1 +
>>  drivers/vfio/mdev/vfio_mdev.c                     |  6 ++++++
>>  include/linux/mdev.h                              |  7 ++++++-
>>  include/linux/mod_devicetable.h                   |  8 ++++++++
>>  samples/vfio-mdev/mbochs.c                        |  2 +-
>>  samples/vfio-mdev/mdpy.c                          |  2 +-
>>  samples/vfio-mdev/mtty.c                          |  2 +-
>>  13 files changed, 59 insertions(+), 11 deletions(-)
>>
>> diff --git a/Documentation/driver-api/vfio-mediated-device.rst
>> b/Documentation/driver-api/vfio-mediated-device.rst
>> index 25eb7d5b834b..0e052072e1d8 100644
>> --- a/Documentation/driver-api/vfio-mediated-device.rst
>> +++ b/Documentation/driver-api/vfio-mediated-device.rst
>> @@ -102,12 +102,14 @@ structure to represent a mediated device's driver::
>>        * @probe: called when new device created
>>        * @remove: called when device removed
>>        * @driver: device driver structure
>> +      * @id_table: the ids serviced by this driver.
> No full stop at the end.


Will fix this.


>
>>        */
>>       struct mdev_driver {
>>  	     const char *name;
>>  	     int  (*probe)  (struct device *dev);
>>  	     void (*remove) (struct device *dev);
>>  	     struct device_driver    driver;
>> +	     const struct mdev_class_id *id_table;
>>       };
>>
>>  A mediated bus driver for mdev should use this structure in the function calls
>> @@ -116,7 +118,7 @@ to register and unregister itself with the core driver:
>>  * Register::
>>
>>      extern int  mdev_register_driver(struct mdev_driver *drv,
>> -				   struct module *owner);
>> +                                     struct module *owner);
>>
> Unrelated change in this patch.


Yes, will fix.


>
>>  * Unregister::
>>
>> @@ -163,7 +165,8 @@ A driver should use the mdev_parent_ops structure in
>> the function call to  register itself with the mdev core driver::
>>
>>  	extern int  mdev_register_device(struct device *dev,
>> -	                                 const struct mdev_parent_ops *ops);
>> +	                                 const struct mdev_parent_ops *ops,
>> +	                                 u8 class_id);
>>
> Cover letter from Change-V2 says that it class_id changed from " use u16 instead u8 for class id"
> But it is still u8 here?


Right, let me fix it in v2.


>
>>  However, the mdev_parent_ops structure is not required in the function call
>> that a driver should use to unregister itself with the mdev core driver::
>> diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c
>> b/drivers/gpu/drm/i915/gvt/kvmgt.c
>> index 23aa3e50cbf8..19d51a35f019 100644
>> --- a/drivers/gpu/drm/i915/gvt/kvmgt.c
>> +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
>> @@ -1625,7 +1625,7 @@ static int kvmgt_host_init(struct device *dev, void
>> *gvt, const void *ops)
>>  		return -EFAULT;
>>  	intel_vgpu_ops.supported_type_groups = kvm_vgpu_type_groups;
>>
>> -	return mdev_register_device(dev, &intel_vgpu_ops);
>> +	return mdev_register_vfio_device(dev, &intel_vgpu_ops);
>>  }
>>
>>  static void kvmgt_host_exit(struct device *dev) diff --git
>> a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c index
>> f0d71ab77c50..246ff0f80944 100644
>> --- a/drivers/s390/cio/vfio_ccw_ops.c
>> +++ b/drivers/s390/cio/vfio_ccw_ops.c
>> @@ -588,7 +588,7 @@ static const struct mdev_parent_ops
>> vfio_ccw_mdev_ops = {
>>
>>  int vfio_ccw_mdev_reg(struct subchannel *sch)  {
>> -	return mdev_register_device(&sch->dev, &vfio_ccw_mdev_ops);
>> +	return mdev_register_vfio_device(&sch->dev, &vfio_ccw_mdev_ops);
>>  }
>>
>>  void vfio_ccw_mdev_unreg(struct subchannel *sch) diff --git
>> a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
>> index 5c0f53c6dde7..7487fc39d2c5 100644
>> --- a/drivers/s390/crypto/vfio_ap_ops.c
>> +++ b/drivers/s390/crypto/vfio_ap_ops.c
>> @@ -1295,7 +1295,8 @@ int vfio_ap_mdev_register(void)  {
>>  	atomic_set(&matrix_dev->available_instances,
>> MAX_ZDEV_ENTRIES_EXT);
>>
>> -	return mdev_register_device(&matrix_dev->device,
>> &vfio_ap_matrix_ops);
>> +	return mdev_register_vfio_device(&matrix_dev->device,
>> +					 &vfio_ap_matrix_ops);
>>  }
>>
>>  void vfio_ap_mdev_unregister(void)
>> diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c
>> index b558d4cfd082..a02c256a3514 100644
>> --- a/drivers/vfio/mdev/mdev_core.c
>> +++ b/drivers/vfio/mdev/mdev_core.c
>> @@ -135,11 +135,14 @@ static int mdev_device_remove_cb(struct device
>> *dev, void *data)
>>   * mdev_register_device : Register a device
>>   * @dev: device structure representing parent device.
>>   * @ops: Parent device operation structure to be registered.
>> + * @id: device id.
>>   *
> It device id here, but in below its class_id. Please make them uniform.


Yes, will fix.


>>   * Add device to list of registered parent devices.
>>   * Returns a negative value on error, otherwise 0.
>>   */
>> -int mdev_register_device(struct device *dev, const struct mdev_parent_ops
>> *ops)
>> +int mdev_register_device(struct device *dev,
>> +			 const struct mdev_parent_ops *ops,
>> +			 u8 class_id)
>>  {
> u16 class_id?


Yes it is.


>
>>  	int ret;
>>  	struct mdev_parent *parent;
>> @@ -175,6 +178,7 @@ int mdev_register_device(struct device *dev, const
>> struct mdev_parent_ops *ops)
>>
>>  	parent->dev = dev;
>>  	parent->ops = ops;
>> +	parent->class_id = class_id;
>>
>>  	if (!mdev_bus_compat_class) {
>>  		mdev_bus_compat_class =
>> class_compat_register("mdev_bus");
>> @@ -208,7 +212,13 @@ int mdev_register_device(struct device *dev, const
>> struct mdev_parent_ops *ops)
>>  		put_device(dev);
>>  	return ret;
>>  }
>> -EXPORT_SYMBOL(mdev_register_device);
>> +
>> +int mdev_register_vfio_device(struct device *dev,
>> +			      const struct mdev_parent_ops *ops) {
>> +	return mdev_register_device(dev, ops, MDEV_ID_VFIO); }
>> +EXPORT_SYMBOL(mdev_register_vfio_device);
>>
>>  /*
>>   * mdev_unregister_device : Unregister a parent device diff --git
>> a/drivers/vfio/mdev/mdev_driver.c b/drivers/vfio/mdev/mdev_driver.c index
>> 0d3223aee20b..b70bbebc9dd3 100644
>> --- a/drivers/vfio/mdev/mdev_driver.c
>> +++ b/drivers/vfio/mdev/mdev_driver.c
>> @@ -69,8 +69,22 @@ static int mdev_remove(struct device *dev)
>>  	return 0;
>>  }
>>
>> +static int mdev_match(struct device *dev, struct device_driver *drv) {
>> +	unsigned int i;
>> +	struct mdev_device *mdev = to_mdev_device(dev);
>> +	struct mdev_driver *mdrv = to_mdev_driver(drv);
>> +	const struct mdev_class_id *ids = mdrv->id_table;
>> +
>> +	for (i = 0; ids[i].id; i++)
>> +		if (ids[i].id == mdev->parent->class_id)
>> +			return 1;
>> +	return 0;
>> +}
>> +
>>  struct bus_type mdev_bus_type = {
>>  	.name		= "mdev",
>> +	.match		= mdev_match,
>>  	.probe		= mdev_probe,
>>  	.remove		= mdev_remove,
>>  };
>> diff --git a/drivers/vfio/mdev/mdev_private.h
>> b/drivers/vfio/mdev/mdev_private.h
>> index 7d922950caaf..e58b07c866b1 100644
>> --- a/drivers/vfio/mdev/mdev_private.h
>> +++ b/drivers/vfio/mdev/mdev_private.h
>> @@ -22,6 +22,7 @@ struct mdev_parent {
>>  	struct list_head type_list;
>>  	/* Synchronize device creation/removal with parent unregistration */
>>  	struct rw_semaphore unreg_sem;
>> +	u8 class_id;
>>  };
>>
>>  struct mdev_device {
>> diff --git a/drivers/vfio/mdev/vfio_mdev.c b/drivers/vfio/mdev/vfio_mdev.c
>> index 30964a4e0a28..fd2a4d9a3f26 100644
>> --- a/drivers/vfio/mdev/vfio_mdev.c
>> +++ b/drivers/vfio/mdev/vfio_mdev.c
>> @@ -120,10 +120,16 @@ static void vfio_mdev_remove(struct device *dev)
>>  	vfio_del_group_dev(dev);
>>  }
>>
>> +static struct mdev_class_id id_table[] = {
>> +	{ MDEV_ID_VFIO },
>> +	{ 0 },
>> +};
>> +
>>  static struct mdev_driver vfio_mdev_driver = {
>>  	.name	= "vfio_mdev",
>>  	.probe	= vfio_mdev_probe,
>>  	.remove	= vfio_mdev_remove,
>> +	.id_table = id_table,
>>  };
>>
>>  static int __init vfio_mdev_init(void)
>> diff --git a/include/linux/mdev.h b/include/linux/mdev.h index
>> 0ce30ca78db0..3ebae310f599 100644
>> --- a/include/linux/mdev.h
>> +++ b/include/linux/mdev.h
>> @@ -118,6 +118,7 @@ struct mdev_type_attribute mdev_type_attr_##_name
>> =		\
>>   * @probe: called when new device created
>>   * @remove: called when device removed
>>   * @driver: device driver structure
>> + * @id_table: the ids serviced by this driver.
>>   *
>>   **/
>>  struct mdev_driver {
>> @@ -125,6 +126,7 @@ struct mdev_driver {
>>  	int  (*probe)(struct device *dev);
>>  	void (*remove)(struct device *dev);
>>  	struct device_driver driver;
>> +	const struct mdev_class_id *id_table;
>>  };
>>
>>  #define to_mdev_driver(drv)	container_of(drv, struct mdev_driver, driver)
>> @@ -135,7 +137,8 @@ const guid_t *mdev_uuid(struct mdev_device *mdev);
>>
>>  extern struct bus_type mdev_bus_type;
>>
>> -int mdev_register_device(struct device *dev, const struct mdev_parent_ops
>> *ops);
>> +int mdev_register_vfio_device(struct device *dev,
>> +			      const struct mdev_parent_ops *ops);
>>  void mdev_unregister_device(struct device *dev);
>>
>>  int mdev_register_driver(struct mdev_driver *drv, struct module *owner);
>> @@ -145,4 +148,6 @@ struct device *mdev_parent_dev(struct mdev_device
>> *mdev);  struct device *mdev_dev(struct mdev_device *mdev);  struct
>> mdev_device *mdev_from_dev(struct device *dev);
>>
>> +#define MDEV_ID_VFIO 1 /* VFIO device */
>> +
> Instead of define, please put them as enum 
>
> enum mdev_class/device_id {
> 	MDEV_ID_VFIO = 1,
> 	/* New entries must be added here */
> };


Ok.


>
>>  #endif /* MDEV_H */
>> diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
>> index 5714fd35a83c..f32c6e44fb1a 100644
>> --- a/include/linux/mod_devicetable.h
>> +++ b/include/linux/mod_devicetable.h
>> @@ -821,4 +821,12 @@ struct wmi_device_id {
>>  	const void *context;
>>  };
>>
>> +/**
>> + * struct mdev_class_id - MDEV device class identifier
>> + * @id: Used to identify a specific class of device, e.g vfio-mdev device.
>> + */
>> +struct mdev_class_id {
>> +	__u16 id;
>> +};
> This is u16 as I guess you wanted as opposed to u8 in other places in patch.


Right.

Thanks


>> +
>>  #endif /* LINUX_MOD_DEVICETABLE_H */
>> diff --git a/samples/vfio-mdev/mbochs.c b/samples/vfio-mdev/mbochs.c index
>> ac5c8c17b1ff..71a4469be85d 100644
>> --- a/samples/vfio-mdev/mbochs.c
>> +++ b/samples/vfio-mdev/mbochs.c
>> @@ -1468,7 +1468,7 @@ static int __init mbochs_dev_init(void)
>>  	if (ret)
>>  		goto failed2;
>>
>> -	ret = mdev_register_device(&mbochs_dev, &mdev_fops);
>> +	ret = mdev_register_vfio_device(&mbochs_dev, &mdev_fops);
>>  	if (ret)
>>  		goto failed3;
>>
>> diff --git a/samples/vfio-mdev/mdpy.c b/samples/vfio-mdev/mdpy.c index
>> cc86bf6566e4..d3029dd27d91 100644
>> --- a/samples/vfio-mdev/mdpy.c
>> +++ b/samples/vfio-mdev/mdpy.c
>> @@ -775,7 +775,7 @@ static int __init mdpy_dev_init(void)
>>  	if (ret)
>>  		goto failed2;
>>
>> -	ret = mdev_register_device(&mdpy_dev, &mdev_fops);
>> +	ret = mdev_register_vfio_device(&mdpy_dev, &mdev_fops);
>>  	if (ret)
>>  		goto failed3;
>>
>> diff --git a/samples/vfio-mdev/mtty.c b/samples/vfio-mdev/mtty.c index
>> 92e770a06ea2..744c88a6b22c 100644
>> --- a/samples/vfio-mdev/mtty.c
>> +++ b/samples/vfio-mdev/mtty.c
>> @@ -1468,7 +1468,7 @@ static int __init mtty_dev_init(void)
>>  	if (ret)
>>  		goto failed2;
>>
>> -	ret = mdev_register_device(&mtty_dev.dev, &mdev_fops);
>> +	ret = mdev_register_vfio_device(&mtty_dev.dev, &mdev_fops);
>>  	if (ret)
>>  		goto failed3;
>>
>> --
>> 2.19.1
Jason Wang Sept. 24, 2019, 11:23 a.m. UTC | #6
On 2019/9/24 上午5:02, Parav Pandit wrote:
> Hi Jason,
>
>
>> -----Original Message-----
>> From: Jason Wang <jasowang@redhat.com>
>> Sent: Monday, September 23, 2019 8:03 AM
>> To: kvm@vger.kernel.org; linux-s390@vger.kernel.org; linux-
>> kernel@vger.kernel.org; dri-devel@lists.freedesktop.org; intel-
>> gfx@lists.freedesktop.org; intel-gvt-dev@lists.freedesktop.org;
>> kwankhede@nvidia.com; alex.williamson@redhat.com; mst@redhat.com;
>> tiwei.bie@intel.com
>> Cc: virtualization@lists.linux-foundation.org; netdev@vger.kernel.org;
>> cohuck@redhat.com; maxime.coquelin@redhat.com;
>> cunming.liang@intel.com; zhihong.wang@intel.com;
>> rob.miller@broadcom.com; xiao.w.wang@intel.com;
>> haotian.wang@sifive.com; zhenyuw@linux.intel.com; zhi.a.wang@intel.com;
>> jani.nikula@linux.intel.com; joonas.lahtinen@linux.intel.com;
>> rodrigo.vivi@intel.com; airlied@linux.ie; daniel@ffwll.ch;
>> farman@linux.ibm.com; pasic@linux.ibm.com; sebott@linux.ibm.com;
>> oberpar@linux.ibm.com; heiko.carstens@de.ibm.com; gor@linux.ibm.com;
>> borntraeger@de.ibm.com; akrowiak@linux.ibm.com; freude@linux.ibm.com;
>> lingshan.zhu@intel.com; Ido Shamay <idos@mellanox.com>;
>> eperezma@redhat.com; lulu@redhat.com; Parav Pandit
>> <parav@mellanox.com>; Jason Wang <jasowang@redhat.com>
>> Subject: [PATCH 1/6] mdev: class id support
>>
>> Mdev bus only supports vfio driver right now, so it doesn't implement match
>> method. But in the future, we may add drivers other than vfio, one example is
>> virtio-mdev[1] driver. This means we need to add device class id support in bus
>> match method to pair the mdev device and mdev driver correctly.
>>
>> So this patch adds id_table to mdev_driver and class_id for mdev parent with
>> the match method for mdev bus.
>>
>> Signed-off-by: Jason Wang <jasowang@redhat.com>
>> ---
>>  Documentation/driver-api/vfio-mediated-device.rst |  7 +++++--
>>  drivers/gpu/drm/i915/gvt/kvmgt.c                  |  2 +-
>>  drivers/s390/cio/vfio_ccw_ops.c                   |  2 +-
>>  drivers/s390/crypto/vfio_ap_ops.c                 |  3 ++-
>>  drivers/vfio/mdev/mdev_core.c                     | 14 ++++++++++++--
>>  drivers/vfio/mdev/mdev_driver.c                   | 14 ++++++++++++++
>>  drivers/vfio/mdev/mdev_private.h                  |  1 +
>>  drivers/vfio/mdev/vfio_mdev.c                     |  6 ++++++
>>  include/linux/mdev.h                              |  7 ++++++-
>>  include/linux/mod_devicetable.h                   |  8 ++++++++
>>  samples/vfio-mdev/mbochs.c                        |  2 +-
>>  samples/vfio-mdev/mdpy.c                          |  2 +-
>>  samples/vfio-mdev/mtty.c                          |  2 +-
>>  13 files changed, 59 insertions(+), 11 deletions(-)
>>
> You additionally need modpost support for id table integration to modifo, modprobe and other tools.
> A small patch similar to this one [1] is needed.
> Please include in the series.
>
> [1] https://lore.kernel.org/patchwork/patch/1046991/


My understanding is this could be done on top and may require uevent
support for the bus. I can try to implement this in V2.

Thanks

>
>

Patch
diff mbox series

diff --git a/Documentation/driver-api/vfio-mediated-device.rst b/Documentation/driver-api/vfio-mediated-device.rst
index 25eb7d5b834b..0e052072e1d8 100644
--- a/Documentation/driver-api/vfio-mediated-device.rst
+++ b/Documentation/driver-api/vfio-mediated-device.rst
@@ -102,12 +102,14 @@  structure to represent a mediated device's driver::
       * @probe: called when new device created
       * @remove: called when device removed
       * @driver: device driver structure
+      * @id_table: the ids serviced by this driver.
       */
      struct mdev_driver {
 	     const char *name;
 	     int  (*probe)  (struct device *dev);
 	     void (*remove) (struct device *dev);
 	     struct device_driver    driver;
+	     const struct mdev_class_id *id_table;
      };
 
 A mediated bus driver for mdev should use this structure in the function calls
@@ -116,7 +118,7 @@  to register and unregister itself with the core driver:
 * Register::
 
     extern int  mdev_register_driver(struct mdev_driver *drv,
-				   struct module *owner);
+                                     struct module *owner);
 
 * Unregister::
 
@@ -163,7 +165,8 @@  A driver should use the mdev_parent_ops structure in the function call to
 register itself with the mdev core driver::
 
 	extern int  mdev_register_device(struct device *dev,
-	                                 const struct mdev_parent_ops *ops);
+	                                 const struct mdev_parent_ops *ops,
+	                                 u8 class_id);
 
 However, the mdev_parent_ops structure is not required in the function call
 that a driver should use to unregister itself with the mdev core driver::
diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
index 23aa3e50cbf8..19d51a35f019 100644
--- a/drivers/gpu/drm/i915/gvt/kvmgt.c
+++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
@@ -1625,7 +1625,7 @@  static int kvmgt_host_init(struct device *dev, void *gvt, const void *ops)
 		return -EFAULT;
 	intel_vgpu_ops.supported_type_groups = kvm_vgpu_type_groups;
 
-	return mdev_register_device(dev, &intel_vgpu_ops);
+	return mdev_register_vfio_device(dev, &intel_vgpu_ops);
 }
 
 static void kvmgt_host_exit(struct device *dev)
diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
index f0d71ab77c50..246ff0f80944 100644
--- a/drivers/s390/cio/vfio_ccw_ops.c
+++ b/drivers/s390/cio/vfio_ccw_ops.c
@@ -588,7 +588,7 @@  static const struct mdev_parent_ops vfio_ccw_mdev_ops = {
 
 int vfio_ccw_mdev_reg(struct subchannel *sch)
 {
-	return mdev_register_device(&sch->dev, &vfio_ccw_mdev_ops);
+	return mdev_register_vfio_device(&sch->dev, &vfio_ccw_mdev_ops);
 }
 
 void vfio_ccw_mdev_unreg(struct subchannel *sch)
diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index 5c0f53c6dde7..7487fc39d2c5 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -1295,7 +1295,8 @@  int vfio_ap_mdev_register(void)
 {
 	atomic_set(&matrix_dev->available_instances, MAX_ZDEV_ENTRIES_EXT);
 
-	return mdev_register_device(&matrix_dev->device, &vfio_ap_matrix_ops);
+	return mdev_register_vfio_device(&matrix_dev->device,
+					 &vfio_ap_matrix_ops);
 }
 
 void vfio_ap_mdev_unregister(void)
diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c
index b558d4cfd082..a02c256a3514 100644
--- a/drivers/vfio/mdev/mdev_core.c
+++ b/drivers/vfio/mdev/mdev_core.c
@@ -135,11 +135,14 @@  static int mdev_device_remove_cb(struct device *dev, void *data)
  * mdev_register_device : Register a device
  * @dev: device structure representing parent device.
  * @ops: Parent device operation structure to be registered.
+ * @id: device id.
  *
  * Add device to list of registered parent devices.
  * Returns a negative value on error, otherwise 0.
  */
-int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops)
+int mdev_register_device(struct device *dev,
+			 const struct mdev_parent_ops *ops,
+			 u8 class_id)
 {
 	int ret;
 	struct mdev_parent *parent;
@@ -175,6 +178,7 @@  int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops)
 
 	parent->dev = dev;
 	parent->ops = ops;
+	parent->class_id = class_id;
 
 	if (!mdev_bus_compat_class) {
 		mdev_bus_compat_class = class_compat_register("mdev_bus");
@@ -208,7 +212,13 @@  int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops)
 		put_device(dev);
 	return ret;
 }
-EXPORT_SYMBOL(mdev_register_device);
+
+int mdev_register_vfio_device(struct device *dev,
+			      const struct mdev_parent_ops *ops)
+{
+	return mdev_register_device(dev, ops, MDEV_ID_VFIO);
+}
+EXPORT_SYMBOL(mdev_register_vfio_device);
 
 /*
  * mdev_unregister_device : Unregister a parent device
diff --git a/drivers/vfio/mdev/mdev_driver.c b/drivers/vfio/mdev/mdev_driver.c
index 0d3223aee20b..b70bbebc9dd3 100644
--- a/drivers/vfio/mdev/mdev_driver.c
+++ b/drivers/vfio/mdev/mdev_driver.c
@@ -69,8 +69,22 @@  static int mdev_remove(struct device *dev)
 	return 0;
 }
 
+static int mdev_match(struct device *dev, struct device_driver *drv)
+{
+	unsigned int i;
+	struct mdev_device *mdev = to_mdev_device(dev);
+	struct mdev_driver *mdrv = to_mdev_driver(drv);
+	const struct mdev_class_id *ids = mdrv->id_table;
+
+	for (i = 0; ids[i].id; i++)
+		if (ids[i].id == mdev->parent->class_id)
+			return 1;
+	return 0;
+}
+
 struct bus_type mdev_bus_type = {
 	.name		= "mdev",
+	.match		= mdev_match,
 	.probe		= mdev_probe,
 	.remove		= mdev_remove,
 };
diff --git a/drivers/vfio/mdev/mdev_private.h b/drivers/vfio/mdev/mdev_private.h
index 7d922950caaf..e58b07c866b1 100644
--- a/drivers/vfio/mdev/mdev_private.h
+++ b/drivers/vfio/mdev/mdev_private.h
@@ -22,6 +22,7 @@  struct mdev_parent {
 	struct list_head type_list;
 	/* Synchronize device creation/removal with parent unregistration */
 	struct rw_semaphore unreg_sem;
+	u8 class_id;
 };
 
 struct mdev_device {
diff --git a/drivers/vfio/mdev/vfio_mdev.c b/drivers/vfio/mdev/vfio_mdev.c
index 30964a4e0a28..fd2a4d9a3f26 100644
--- a/drivers/vfio/mdev/vfio_mdev.c
+++ b/drivers/vfio/mdev/vfio_mdev.c
@@ -120,10 +120,16 @@  static void vfio_mdev_remove(struct device *dev)
 	vfio_del_group_dev(dev);
 }
 
+static struct mdev_class_id id_table[] = {
+	{ MDEV_ID_VFIO },
+	{ 0 },
+};
+
 static struct mdev_driver vfio_mdev_driver = {
 	.name	= "vfio_mdev",
 	.probe	= vfio_mdev_probe,
 	.remove	= vfio_mdev_remove,
+	.id_table = id_table,
 };
 
 static int __init vfio_mdev_init(void)
diff --git a/include/linux/mdev.h b/include/linux/mdev.h
index 0ce30ca78db0..3ebae310f599 100644
--- a/include/linux/mdev.h
+++ b/include/linux/mdev.h
@@ -118,6 +118,7 @@  struct mdev_type_attribute mdev_type_attr_##_name =		\
  * @probe: called when new device created
  * @remove: called when device removed
  * @driver: device driver structure
+ * @id_table: the ids serviced by this driver.
  *
  **/
 struct mdev_driver {
@@ -125,6 +126,7 @@  struct mdev_driver {
 	int  (*probe)(struct device *dev);
 	void (*remove)(struct device *dev);
 	struct device_driver driver;
+	const struct mdev_class_id *id_table;
 };
 
 #define to_mdev_driver(drv)	container_of(drv, struct mdev_driver, driver)
@@ -135,7 +137,8 @@  const guid_t *mdev_uuid(struct mdev_device *mdev);
 
 extern struct bus_type mdev_bus_type;
 
-int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops);
+int mdev_register_vfio_device(struct device *dev,
+			      const struct mdev_parent_ops *ops);
 void mdev_unregister_device(struct device *dev);
 
 int mdev_register_driver(struct mdev_driver *drv, struct module *owner);
@@ -145,4 +148,6 @@  struct device *mdev_parent_dev(struct mdev_device *mdev);
 struct device *mdev_dev(struct mdev_device *mdev);
 struct mdev_device *mdev_from_dev(struct device *dev);
 
+#define MDEV_ID_VFIO 1 /* VFIO device */
+
 #endif /* MDEV_H */
diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
index 5714fd35a83c..f32c6e44fb1a 100644
--- a/include/linux/mod_devicetable.h
+++ b/include/linux/mod_devicetable.h
@@ -821,4 +821,12 @@  struct wmi_device_id {
 	const void *context;
 };
 
+/**
+ * struct mdev_class_id - MDEV device class identifier
+ * @id: Used to identify a specific class of device, e.g vfio-mdev device.
+ */
+struct mdev_class_id {
+	__u16 id;
+};
+
 #endif /* LINUX_MOD_DEVICETABLE_H */
diff --git a/samples/vfio-mdev/mbochs.c b/samples/vfio-mdev/mbochs.c
index ac5c8c17b1ff..71a4469be85d 100644
--- a/samples/vfio-mdev/mbochs.c
+++ b/samples/vfio-mdev/mbochs.c
@@ -1468,7 +1468,7 @@  static int __init mbochs_dev_init(void)
 	if (ret)
 		goto failed2;
 
-	ret = mdev_register_device(&mbochs_dev, &mdev_fops);
+	ret = mdev_register_vfio_device(&mbochs_dev, &mdev_fops);
 	if (ret)
 		goto failed3;
 
diff --git a/samples/vfio-mdev/mdpy.c b/samples/vfio-mdev/mdpy.c
index cc86bf6566e4..d3029dd27d91 100644
--- a/samples/vfio-mdev/mdpy.c
+++ b/samples/vfio-mdev/mdpy.c
@@ -775,7 +775,7 @@  static int __init mdpy_dev_init(void)
 	if (ret)
 		goto failed2;
 
-	ret = mdev_register_device(&mdpy_dev, &mdev_fops);
+	ret = mdev_register_vfio_device(&mdpy_dev, &mdev_fops);
 	if (ret)
 		goto failed3;
 
diff --git a/samples/vfio-mdev/mtty.c b/samples/vfio-mdev/mtty.c
index 92e770a06ea2..744c88a6b22c 100644
--- a/samples/vfio-mdev/mtty.c
+++ b/samples/vfio-mdev/mtty.c
@@ -1468,7 +1468,7 @@  static int __init mtty_dev_init(void)
 	if (ret)
 		goto failed2;
 
-	ret = mdev_register_device(&mtty_dev.dev, &mdev_fops);
+	ret = mdev_register_vfio_device(&mtty_dev.dev, &mdev_fops);
 	if (ret)
 		goto failed3;