Re: [PATCH V11 1/6] mdev: class id support

[Kirti Wankhede <kwankhede@xxxxxxxxxx>]

On 11/7/2019 8:41 PM, Jason Wang 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,
> 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.
>
> Reviewed-by: Parav Pandit <parav@xxxxxxxxxxxx>
> Reviewed-by: Cornelia Huck <cohuck@xxxxxxxxxx>
> Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>

Reviewed-by: Kirti Wankhede <kwankhede@xxxxxxxxxx>

Thanks,
Kirti

> ---
>   .../driver-api/vfio-mediated-device.rst       |  5 ++++
>   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                 | 17 +++++++++++++
>   drivers/vfio/mdev/mdev_driver.c               | 25 +++++++++++++++++++
>   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, 76 insertions(+)
>
> diff --git a/Documentation/driver-api/vfio-mediated-device.rst b/Documentation/driver-api/vfio-mediated-device.rst
> index 25eb7d5b834b..6709413bee29 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
> @@ -170,6 +172,9 @@ that a driver should use to unregister itself with the mdev core driver::
>   
>   	extern void mdev_unregister_device(struct device *dev);
>   
> +It is also required to specify the class_id in create() callback through::
> +
> +	int mdev_set_class(struct mdev_device *mdev, u16 id);
>   
>   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..7bfa2e46e829 100644
> --- a/drivers/vfio/mdev/mdev_core.c
> +++ b/drivers/vfio/mdev/mdev_core.c
> @@ -45,6 +45,17 @@ 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;
> @@ -324,6 +335,12 @@ int mdev_device_create(struct kobject *kobj,
>   	if (ret)
>   		goto ops_create_fail;
>   
> +	if (!mdev->class_id) {
> +		ret = -EINVAL;
> +		dev_warn(dev, "mdev vendor driver failed to specify device class\n");
> +		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..ed06433693e8 100644
> --- a/drivers/vfio/mdev/mdev_driver.c
> +++ b/drivers/vfio/mdev/mdev_driver.c
> @@ -69,8 +69,33 @@ 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;
> +
> +	if (!ids)
> +		return 0;
> +
> +	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..38431e9ef7f5 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 vfio_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 = vfio_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;
>   }
>   
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