[PATCH V4 1/6] mdev: class id support

Parav Pandit parav at mellanox.com
Sun Oct 20 23:25:10 UTC 2019



> -----Original Message-----
> From: kvm-owner at vger.kernel.org <kvm-owner at vger.kernel.org> On Behalf
> Of Jason Wang
> Sent: Thursday, October 17, 2019 5:49 AM
> To: kvm at vger.kernel.org; linux-s390 at vger.kernel.org; linux-
> kernel at vger.kernel.org; dri-devel at lists.freedesktop.org; intel-
> gfx at lists.freedesktop.org; intel-gvt-dev at lists.freedesktop.org;
> kwankhede at nvidia.com; alex.williamson at redhat.com; mst at redhat.com;
> tiwei.bie at intel.com
> Cc: virtualization at lists.linux-foundation.org; netdev at vger.kernel.org;
> cohuck at redhat.com; maxime.coquelin at redhat.com;
> cunming.liang at intel.com; zhihong.wang at intel.com;
> rob.miller at broadcom.com; xiao.w.wang at intel.com;
> haotian.wang at sifive.com; zhenyuw at linux.intel.com; zhi.a.wang at intel.com;
> jani.nikula at linux.intel.com; joonas.lahtinen at linux.intel.com;
> rodrigo.vivi at intel.com; airlied at linux.ie; daniel at ffwll.ch;
> farman at linux.ibm.com; pasic at linux.ibm.com; sebott at linux.ibm.com;
> oberpar at linux.ibm.com; heiko.carstens at de.ibm.com; gor at linux.ibm.com;
> borntraeger at de.ibm.com; akrowiak at linux.ibm.com; freude at linux.ibm.com;
> lingshan.zhu at intel.com; Ido Shamay <idos at mellanox.com>;
> eperezma at redhat.com; lulu at redhat.com; Parav Pandit
> <parav at mellanox.com>; christophe.de.dinechin at gmail.com;
> kevin.tian at intel.com; stefanha at redhat.com; Jason Wang
> <jasowang at redhat.com>
> Subject: [PATCH V4 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, the first
> driver could be virtio-mdev. 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 device
> with the match method for mdev bus.
> 
> Signed-off-by: Jason Wang <jasowang at redhat.com>
> ---
>  .../driver-api/vfio-mediated-device.rst       |  7 +++++-
>  drivers/gpu/drm/i915/gvt/kvmgt.c              |  1 +
>  drivers/s390/cio/vfio_ccw_ops.c               |  1 +
>  drivers/s390/crypto/vfio_ap_ops.c             |  1 +
>  drivers/vfio/mdev/mdev_core.c                 | 18 +++++++++++++++
>  drivers/vfio/mdev/mdev_driver.c               | 22 +++++++++++++++++++
>  drivers/vfio/mdev/mdev_private.h              |  1 +
>  drivers/vfio/mdev/vfio_mdev.c                 |  6 +++++
>  include/linux/mdev.h                          |  8 +++++++
>  include/linux/mod_devicetable.h               |  8 +++++++
>  samples/vfio-mdev/mbochs.c                    |  1 +
>  samples/vfio-mdev/mdpy.c                      |  1 +
>  samples/vfio-mdev/mtty.c                      |  1 +
>  13 files changed, 75 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/driver-api/vfio-mediated-device.rst
> b/Documentation/driver-api/vfio-mediated-device.rst
> index 25eb7d5b834b..f9a78d75a67a 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 @@ -165,12 +167,15 @@ register itself with the mdev core driver::
>  	extern int  mdev_register_device(struct device *dev,
>  	                                 const struct mdev_parent_ops *ops);
> 
> +It is also required to specify the class_id in create() callback through::
> +
> +	int mdev_set_class(struct mdev_device *mdev, u16 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::
> 
>  	extern void mdev_unregister_device(struct device *dev);
> 
> -
>  Mediated Device Management Interface Through sysfs
> ==================================================
> 
> diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c
> b/drivers/gpu/drm/i915/gvt/kvmgt.c
> index 343d79c1cb7e..6420f0dbd31b 100644
> --- a/drivers/gpu/drm/i915/gvt/kvmgt.c
> +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
> @@ -678,6 +678,7 @@ static int intel_vgpu_create(struct kobject *kobj,
> struct mdev_device *mdev)
>  		     dev_name(mdev_dev(mdev)));
>  	ret = 0;
> 
> +	mdev_set_class(mdev, MDEV_CLASS_ID_VFIO);
>  out:
>  	return ret;
>  }
> diff --git a/drivers/s390/cio/vfio_ccw_ops.c
> b/drivers/s390/cio/vfio_ccw_ops.c index f0d71ab77c50..cf2c013ae32f 100644
> --- a/drivers/s390/cio/vfio_ccw_ops.c
> +++ b/drivers/s390/cio/vfio_ccw_ops.c
> @@ -129,6 +129,7 @@ static int vfio_ccw_mdev_create(struct kobject *kobj,
> struct mdev_device *mdev)
>  			   private->sch->schid.ssid,
>  			   private->sch->schid.sch_no);
> 
> +	mdev_set_class(mdev, MDEV_CLASS_ID_VFIO);
>  	return 0;
>  }
> 
> diff --git a/drivers/s390/crypto/vfio_ap_ops.c
> b/drivers/s390/crypto/vfio_ap_ops.c
> index 5c0f53c6dde7..07c31070afeb 100644
> --- a/drivers/s390/crypto/vfio_ap_ops.c
> +++ b/drivers/s390/crypto/vfio_ap_ops.c
> @@ -343,6 +343,7 @@ static int vfio_ap_mdev_create(struct kobject *kobj,
> struct mdev_device *mdev)
>  	list_add(&matrix_mdev->node, &matrix_dev->mdev_list);
>  	mutex_unlock(&matrix_dev->lock);
> 
> +	mdev_set_class(mdev, MDEV_CLASS_ID_VFIO);
>  	return 0;
>  }
> 
> diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c
> index b558d4cfd082..3a9c52d71b4e 100644
> --- a/drivers/vfio/mdev/mdev_core.c
> +++ b/drivers/vfio/mdev/mdev_core.c
> @@ -45,6 +45,16 @@ void mdev_set_drvdata(struct mdev_device *mdev,
> void *data)  }  EXPORT_SYMBOL(mdev_set_drvdata);
> 
> +/* Specify the class for the mdev device, this must be called during
> + * create() callback.
> + */
> +void mdev_set_class(struct mdev_device *mdev, u16 id) {
> +	WARN_ON(mdev->class_id);
> +	mdev->class_id = id;
> +}
> +EXPORT_SYMBOL(mdev_set_class);
> +
>  struct device *mdev_dev(struct mdev_device *mdev)  {
>  	return &mdev->dev;
> @@ -135,6 +145,7 @@ 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: class id.
>   *
>   * Add device to list of registered parent devices.
>   * Returns a negative value on error, otherwise 0.
> @@ -324,6 +335,13 @@ int mdev_device_create(struct kobject *kobj,
>  	if (ret)
>  		goto ops_create_fail;
> 
> +	if (!mdev->class_id) {
> +		ret = -EINVAL;
> +		WARN(1, "class id must be specified for device %s\n",
> +		     dev_name(dev));
> +		goto add_fail;
> +	}
> +
>  	ret = device_add(&mdev->dev);
>  	if (ret)
>  		goto add_fail;
> diff --git a/drivers/vfio/mdev/mdev_driver.c
> b/drivers/vfio/mdev/mdev_driver.c index 0d3223aee20b..319d886ffaf7
> 100644
> --- a/drivers/vfio/mdev/mdev_driver.c
> +++ b/drivers/vfio/mdev/mdev_driver.c
> @@ -69,8 +69,30 @@ 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->class_id)
> +			return 1;
> +	return 0;
> +}
> +
> +static int mdev_uevent(struct device *dev, struct kobj_uevent_env *env)
> +{
> +	struct mdev_device *mdev = to_mdev_device(dev);
> +
> +	return add_uevent_var(env, "MODALIAS=mdev:c%02X", mdev-
> >class_id); }
> +
>  struct bus_type mdev_bus_type = {
>  	.name		= "mdev",
> +	.match		= mdev_match,
> +	.uevent		= mdev_uevent,
>  	.probe		= mdev_probe,
>  	.remove		= mdev_remove,
>  };
> diff --git a/drivers/vfio/mdev/mdev_private.h
> b/drivers/vfio/mdev/mdev_private.h
> index 7d922950caaf..c65f436c1869 100644
> --- a/drivers/vfio/mdev/mdev_private.h
> +++ b/drivers/vfio/mdev/mdev_private.h
> @@ -33,6 +33,7 @@ struct mdev_device {
>  	struct kobject *type_kobj;
>  	struct device *iommu_device;
>  	bool active;
> +	u16 class_id;
>  };
> 
>  #define to_mdev_device(dev)	container_of(dev, struct mdev_device, dev)
> diff --git a/drivers/vfio/mdev/vfio_mdev.c b/drivers/vfio/mdev/vfio_mdev.c
> index 30964a4e0a28..7b24ee9cb8dd 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 const struct mdev_class_id id_table[] = {
> +	{ MDEV_CLASS_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..78b69d09eb54 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)
> @@ -132,6 +134,7 @@ struct mdev_driver {  void *mdev_get_drvdata(struct
> mdev_device *mdev);  void mdev_set_drvdata(struct mdev_device *mdev,
> void *data);  const guid_t *mdev_uuid(struct mdev_device *mdev);
> +void mdev_set_class(struct mdev_device *mdev, u16 id);
> 
>  extern struct bus_type mdev_bus_type;
> 
> @@ -145,4 +148,9 @@ 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);
> 
> +enum {
> +	MDEV_CLASS_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;
> +};
> +
>  #endif /* LINUX_MOD_DEVICETABLE_H */
> diff --git a/samples/vfio-mdev/mbochs.c b/samples/vfio-mdev/mbochs.c
> index ac5c8c17b1ff..115bc5074656 100644
> --- a/samples/vfio-mdev/mbochs.c
> +++ b/samples/vfio-mdev/mbochs.c
> @@ -561,6 +561,7 @@ static int mbochs_create(struct kobject *kobj, struct
> mdev_device *mdev)
>  	mbochs_reset(mdev);
> 
>  	mbochs_used_mbytes += type->mbytes;
> +	mdev_set_class(mdev, MDEV_CLASS_ID_VFIO);
>  	return 0;
> 
>  err_mem:
> diff --git a/samples/vfio-mdev/mdpy.c b/samples/vfio-mdev/mdpy.c index
> cc86bf6566e4..665614574d50 100644
> --- a/samples/vfio-mdev/mdpy.c
> +++ b/samples/vfio-mdev/mdpy.c
> @@ -269,6 +269,7 @@ static int mdpy_create(struct kobject *kobj, struct
> mdev_device *mdev)
>  	mdpy_reset(mdev);
> 
>  	mdpy_count++;
> +	mdev_set_class(mdev, MDEV_CLASS_ID_VFIO);
>  	return 0;
>  }
> 
> diff --git a/samples/vfio-mdev/mtty.c b/samples/vfio-mdev/mtty.c index
> ce84a300a4da..90da12ff7fd9 100644
> --- a/samples/vfio-mdev/mtty.c
> +++ b/samples/vfio-mdev/mtty.c
> @@ -755,6 +755,7 @@ static int mtty_create(struct kobject *kobj, struct
> mdev_device *mdev)
>  	list_add(&mdev_state->next, &mdev_devices_list);
>  	mutex_unlock(&mdev_list_lock);
> 
> +	mdev_set_class(mdev, MDEV_CLASS_ID_VFIO);
>  	return 0;
>  }
> 
> --
> 2.19.1
Reviewed-by: Parav Pandit <parav at mellanox.com>



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