[RFC PATCH 2/2] mdev: introduce device specific ops

Jason Wang jasowang at redhat.com
Tue Sep 17 10:16:46 UTC 2019


On 2019/9/17 下午4:09, Tian, Kevin wrote:
>> From: Jason Wang
>> Sent: Thursday, September 12, 2019 5:40 PM
>>
>> Currently, except for the crate and remove. The rest fields of
>> mdev_parent_ops is just designed for vfio-mdev driver and may not help
>> for kernel mdev driver. So follow the device id support by previous
>> patch, this patch introduces device specific ops which points to
>> device specific ops (e.g vfio ops). This allows the future drivers
>> like virtio-mdev to implement its own device specific ops.
> Can you give an example about what ops might be required to support
> kernel mdev driver? I know you posted a link earlier, but putting a small
> example here can save time and avoid inconsistent understanding. Then
> it will help whether the proposed split makes sense or there is a
> possibility of redefining the callbacks to meet the both requirements.
> imo those callbacks fulfill some basic requirements when mediating
> a device...


I put it in the cover letter.

The link is https://lkml.org/lkml/2019/9/10/135 which abuses the current 
VFIO based mdev parent ops.

Thanks


>> Signed-off-by: Jason Wang <jasowang at redhat.com>
>> ---
>>   drivers/gpu/drm/i915/gvt/kvmgt.c  | 14 +++---
>>   drivers/s390/cio/vfio_ccw_ops.c   | 14 +++---
>>   drivers/s390/crypto/vfio_ap_ops.c | 10 +++--
>>   drivers/vfio/mdev/vfio_mdev.c     | 30 +++++++------
>>   include/linux/mdev.h              | 72 ++++++++++++++++++-------------
>>   samples/vfio-mdev/mbochs.c        | 16 ++++---
>>   samples/vfio-mdev/mdpy.c          | 16 ++++---
>>   samples/vfio-mdev/mtty.c          | 14 +++---
>>   8 files changed, 113 insertions(+), 73 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c
>> b/drivers/gpu/drm/i915/gvt/kvmgt.c
>> index 19d51a35f019..64823998fd58 100644
>> --- a/drivers/gpu/drm/i915/gvt/kvmgt.c
>> +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
>> @@ -1600,20 +1600,22 @@ static const struct attribute_group
>> *intel_vgpu_groups[] = {
>>   	NULL,
>>   };
>>
>> -static struct mdev_parent_ops intel_vgpu_ops = {
>> -	.mdev_attr_groups       = intel_vgpu_groups,
>> -	.create			= intel_vgpu_create,
>> -	.remove			= intel_vgpu_remove,
>> -
>> +static struct vfio_mdev_parent_ops intel_vfio_vgpu_ops = {
>>   	.open			= intel_vgpu_open,
>>   	.release		= intel_vgpu_release,
>> -
>>   	.read			= intel_vgpu_read,
>>   	.write			= intel_vgpu_write,
>>   	.mmap			= intel_vgpu_mmap,
>>   	.ioctl			= intel_vgpu_ioctl,
>>   };
>>
>> +static struct mdev_parent_ops intel_vgpu_ops = {
>> +	.mdev_attr_groups       = intel_vgpu_groups,
>> +	.create			= intel_vgpu_create,
>> +	.remove			= intel_vgpu_remove,
>> +	.device_ops	        = &intel_vfio_vgpu_ops,
>> +};
>> +
>>   static int kvmgt_host_init(struct device *dev, void *gvt, const void *ops)
>>   {
>>   	struct attribute **kvm_type_attrs;
>> diff --git a/drivers/s390/cio/vfio_ccw_ops.c
>> b/drivers/s390/cio/vfio_ccw_ops.c
>> index f87d9409e290..96e9f18100ae 100644
>> --- a/drivers/s390/cio/vfio_ccw_ops.c
>> +++ b/drivers/s390/cio/vfio_ccw_ops.c
>> @@ -564,11 +564,7 @@ static ssize_t vfio_ccw_mdev_ioctl(struct
>> mdev_device *mdev,
>>   	}
>>   }
>>
>> -static const struct mdev_parent_ops vfio_ccw_mdev_ops = {
>> -	.owner			= THIS_MODULE,
>> -	.supported_type_groups  = mdev_type_groups,
>> -	.create			= vfio_ccw_mdev_create,
>> -	.remove			= vfio_ccw_mdev_remove,
>> +static const struct vfio_mdev_parent_ops vfio_mdev_ops = {
>>   	.open			= vfio_ccw_mdev_open,
>>   	.release		= vfio_ccw_mdev_release,
>>   	.read			= vfio_ccw_mdev_read,
>> @@ -576,6 +572,14 @@ static const struct mdev_parent_ops
>> vfio_ccw_mdev_ops = {
>>   	.ioctl			= vfio_ccw_mdev_ioctl,
>>   };
>>
>> +static const struct mdev_parent_ops vfio_ccw_mdev_ops = {
>> +	.owner			= THIS_MODULE,
>> +	.supported_type_groups  = mdev_type_groups,
>> +	.create			= vfio_ccw_mdev_create,
>> +	.remove			= vfio_ccw_mdev_remove,
>> +	.device_ops		= &vfio_mdev_ops,
>> +};
>> +
>>   int vfio_ccw_mdev_reg(struct subchannel *sch)
>>   {
>>   	return mdev_register_vfio_device(&sch->dev,
>> &vfio_ccw_mdev_ops);
>> diff --git a/drivers/s390/crypto/vfio_ap_ops.c
>> b/drivers/s390/crypto/vfio_ap_ops.c
>> index eacbde3c7a97..a48282bff066 100644
>> --- a/drivers/s390/crypto/vfio_ap_ops.c
>> +++ b/drivers/s390/crypto/vfio_ap_ops.c
>> @@ -1280,15 +1280,19 @@ static ssize_t vfio_ap_mdev_ioctl(struct
>> mdev_device *mdev,
>>   	return ret;
>>   }
>>
>> +static const struct vfio_mdev_parent_ops vfio_mdev_ops = {
>> +	.open			= vfio_ap_mdev_open,
>> +	.release		= vfio_ap_mdev_release,
>> +	.ioctl			= vfio_ap_mdev_ioctl,
>> +};
>> +
>>   static const struct mdev_parent_ops vfio_ap_matrix_ops = {
>>   	.owner			= THIS_MODULE,
>>   	.supported_type_groups	= vfio_ap_mdev_type_groups,
>>   	.mdev_attr_groups	= vfio_ap_mdev_attr_groups,
>>   	.create			= vfio_ap_mdev_create,
>>   	.remove			= vfio_ap_mdev_remove,
>> -	.open			= vfio_ap_mdev_open,
>> -	.release		= vfio_ap_mdev_release,
>> -	.ioctl			= vfio_ap_mdev_ioctl,
>> +	.device_ops		= &vfio_mdev_ops,
>>   };
>>
>>   int vfio_ap_mdev_register(void)
>> diff --git a/drivers/vfio/mdev/vfio_mdev.c
>> b/drivers/vfio/mdev/vfio_mdev.c
>> index 887c57f10880..1196fbb6c3d2 100644
>> --- a/drivers/vfio/mdev/vfio_mdev.c
>> +++ b/drivers/vfio/mdev/vfio_mdev.c
>> @@ -25,15 +25,16 @@ static int vfio_mdev_open(void *device_data)
>>   {
>>   	struct mdev_device *mdev = device_data;
>>   	struct mdev_parent *parent = mdev->parent;
>> +	const struct vfio_mdev_parent_ops *ops = parent->ops-
>>> device_ops;
>>   	int ret;
>>
>> -	if (unlikely(!parent->ops->open))
>> +	if (unlikely(!ops->open))
>>   		return -EINVAL;
>>
>>   	if (!try_module_get(THIS_MODULE))
>>   		return -ENODEV;
>>
>> -	ret = parent->ops->open(mdev);
>> +	ret = ops->open(mdev);
>>   	if (ret)
>>   		module_put(THIS_MODULE);
>>
>> @@ -44,9 +45,10 @@ static void vfio_mdev_release(void *device_data)
>>   {
>>   	struct mdev_device *mdev = device_data;
>>   	struct mdev_parent *parent = mdev->parent;
>> +	const struct vfio_mdev_parent_ops *ops = parent->ops-
>>> device_ops;
>> -	if (likely(parent->ops->release))
>> -		parent->ops->release(mdev);
>> +	if (likely(ops->release))
>> +		ops->release(mdev);
>>
>>   	module_put(THIS_MODULE);
>>   }
>> @@ -56,11 +58,12 @@ static long vfio_mdev_unlocked_ioctl(void
>> *device_data,
>>   {
>>   	struct mdev_device *mdev = device_data;
>>   	struct mdev_parent *parent = mdev->parent;
>> +	const struct vfio_mdev_parent_ops *ops = parent->ops-
>>> device_ops;
>> -	if (unlikely(!parent->ops->ioctl))
>> +	if (unlikely(!ops->ioctl))
>>   		return -EINVAL;
>>
>> -	return parent->ops->ioctl(mdev, cmd, arg);
>> +	return ops->ioctl(mdev, cmd, arg);
>>   }
>>
>>   static ssize_t vfio_mdev_read(void *device_data, char __user *buf,
>> @@ -68,11 +71,12 @@ static ssize_t vfio_mdev_read(void *device_data,
>> char __user *buf,
>>   {
>>   	struct mdev_device *mdev = device_data;
>>   	struct mdev_parent *parent = mdev->parent;
>> +	const struct vfio_mdev_parent_ops *ops = parent->ops-
>>> device_ops;
>> -	if (unlikely(!parent->ops->read))
>> +	if (unlikely(!ops->read))
>>   		return -EINVAL;
>>
>> -	return parent->ops->read(mdev, buf, count, ppos);
>> +	return ops->read(mdev, buf, count, ppos);
>>   }
>>
>>   static ssize_t vfio_mdev_write(void *device_data, const char __user *buf,
>> @@ -80,22 +84,24 @@ static ssize_t vfio_mdev_write(void *device_data,
>> const char __user *buf,
>>   {
>>   	struct mdev_device *mdev = device_data;
>>   	struct mdev_parent *parent = mdev->parent;
>> +	const struct vfio_mdev_parent_ops *ops = parent->ops-
>>> device_ops;
>> -	if (unlikely(!parent->ops->write))
>> +	if (unlikely(!ops->write))
>>   		return -EINVAL;
>>
>> -	return parent->ops->write(mdev, buf, count, ppos);
>> +	return ops->write(mdev, buf, count, ppos);
>>   }
>>
>>   static int vfio_mdev_mmap(void *device_data, struct vm_area_struct
>> *vma)
>>   {
>>   	struct mdev_device *mdev = device_data;
>>   	struct mdev_parent *parent = mdev->parent;
>> +	const struct vfio_mdev_parent_ops *ops = parent->ops-
>>> device_ops;
>> -	if (unlikely(!parent->ops->mmap))
>> +	if (unlikely(!ops->mmap))
>>   		return -EINVAL;
>>
>> -	return parent->ops->mmap(mdev, vma);
>> +	return ops->mmap(mdev, vma);
>>   }
>>
>>   static const struct vfio_device_ops vfio_mdev_dev_ops = {
>> diff --git a/include/linux/mdev.h b/include/linux/mdev.h
>> index f85045392120..3b8a76bc69cf 100644
>> --- a/include/linux/mdev.h
>> +++ b/include/linux/mdev.h
>> @@ -27,27 +27,9 @@ int mdev_set_iommu_device(struct device *dev,
>> struct device *iommu_device);
>>   struct device *mdev_get_iommu_device(struct device *dev);
>>
>>   /**
>> - * struct mdev_parent_ops - Structure to be registered for each parent
>> device to
>> - * register the device to mdev module.
>> + * struct vfio_mdev_parent_ops - Structure to be registered for each
>> + * parent device to register the device to vfio-mdev module.
>>    *
>> - * @owner:		The module owner.
>> - * @dev_attr_groups:	Attributes of the parent device.
>> - * @mdev_attr_groups:	Attributes of the mediated device.
>> - * @supported_type_groups: Attributes to define supported types. It is
>> mandatory
>> - *			to provide supported types.
>> - * @create:		Called to allocate basic resources in parent device's
>> - *			driver for a particular mediated device. It is
>> - *			mandatory to provide create ops.
>> - *			@kobj: kobject of type for which 'create' is called.
>> - *			@mdev: mdev_device structure on of mediated
>> device
>> - *			      that is being created
>> - *			Returns integer: success (0) or error (< 0)
>> - * @remove:		Called to free resources in parent device's driver for
>> a
>> - *			a mediated device. It is mandatory to provide
>> 'remove'
>> - *			ops.
>> - *			@mdev: mdev_device device structure which is
>> being
>> - *			       destroyed
>> - *			Returns integer: success (0) or error (< 0)
>>    * @open:		Open mediated device.
>>    *			@mdev: mediated device.
>>    *			Returns integer: success (0) or error (< 0)
>> @@ -72,6 +54,43 @@ struct device *mdev_get_iommu_device(struct
>> device *dev);
>>    * @mmap:		mmap callback
>>    *			@mdev: mediated device structure
>>    *			@vma: vma structure
>> + */
>> +struct vfio_mdev_parent_ops {
>> +	int     (*open)(struct mdev_device *mdev);
>> +	void    (*release)(struct mdev_device *mdev);
>> +	ssize_t (*read)(struct mdev_device *mdev, char __user *buf,
>> +			size_t count, loff_t *ppos);
>> +	ssize_t (*write)(struct mdev_device *mdev, const char __user *buf,
>> +			 size_t count, loff_t *ppos);
>> +	long	(*ioctl)(struct mdev_device *mdev, unsigned int cmd,
>> +			 unsigned long arg);
>> +	int	(*mmap)(struct mdev_device *mdev, struct vm_area_struct
>> *vma);
>> +};
>> +
>> +/**
>> + * struct mdev_parent_ops - Structure to be registered for each parent
>> device to
>> + * register the device to mdev module.
>> + *
>> + * @owner:		The module owner.
>> + * @dev_attr_groups:	Attributes of the parent device.
>> + * @mdev_attr_groups:	Attributes of the mediated device.
>> + * @supported_type_groups: Attributes to define supported types. It is
>> mandatory
>> + *			to provide supported types.
>> + * @create:		Called to allocate basic resources in parent device's
>> + *			driver for a particular mediated device. It is
>> + *			mandatory to provide create ops.
>> + *			@kobj: kobject of type for which 'create' is called.
>> + *			@mdev: mdev_device structure on of mediated
>> device
>> + *			      that is being created
>> + *			Returns integer: success (0) or error (< 0)
>> + * @remove:		Called to free resources in parent device's driver for
>> a
>> + *			a mediated device. It is mandatory to provide
>> 'remove'
>> + *			ops.
>> + *			@mdev: mdev_device device structure which is
>> being
>> + *			       destroyed
>> + *			Returns integer: success (0) or error (< 0)
>> + * @device_ops:         Device specific emulation callback.
>> + *
>>    * Parent device that support mediated device should be registered with
>> mdev
>>    * module with mdev_parent_ops structure.
>>    **/
>> @@ -83,15 +102,7 @@ struct mdev_parent_ops {
>>
>>   	int     (*create)(struct kobject *kobj, struct mdev_device *mdev);
>>   	int     (*remove)(struct mdev_device *mdev);
>> -	int     (*open)(struct mdev_device *mdev);
>> -	void    (*release)(struct mdev_device *mdev);
>> -	ssize_t (*read)(struct mdev_device *mdev, char __user *buf,
>> -			size_t count, loff_t *ppos);
>> -	ssize_t (*write)(struct mdev_device *mdev, const char __user *buf,
>> -			 size_t count, loff_t *ppos);
>> -	long	(*ioctl)(struct mdev_device *mdev, unsigned int cmd,
>> -			 unsigned long arg);
>> -	int	(*mmap)(struct mdev_device *mdev, struct vm_area_struct
>> *vma);
>> +	const void *device_ops;
>>   };
>>
>>   /* interface for exporting mdev supported type attributes */
>> @@ -137,7 +148,8 @@ const guid_t *mdev_uuid(struct mdev_device
>> *mdev);
>>
>>   extern struct bus_type mdev_bus_type;
>>
>> -int mdev_register_vfio_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);
>> diff --git a/samples/vfio-mdev/mbochs.c b/samples/vfio-mdev/mbochs.c
>> index 71a4469be85d..53ceb357f152 100644
>> --- a/samples/vfio-mdev/mbochs.c
>> +++ b/samples/vfio-mdev/mbochs.c
>> @@ -1418,12 +1418,7 @@ static struct attribute_group
>> *mdev_type_groups[] = {
>>   	NULL,
>>   };
>>
>> -static const struct mdev_parent_ops mdev_fops = {
>> -	.owner			= THIS_MODULE,
>> -	.mdev_attr_groups	= mdev_dev_groups,
>> -	.supported_type_groups	= mdev_type_groups,
>> -	.create			= mbochs_create,
>> -	.remove			= mbochs_remove,
>> +static const struct vfio_mdev_parent_ops vfio_mdev_ops = {
>>   	.open			= mbochs_open,
>>   	.release		= mbochs_close,
>>   	.read			= mbochs_read,
>> @@ -1432,6 +1427,15 @@ static const struct mdev_parent_ops mdev_fops
>> = {
>>   	.mmap			= mbochs_mmap,
>>   };
>>
>> +static const struct mdev_parent_ops mdev_fops = {
>> +	.owner			= THIS_MODULE,
>> +	.mdev_attr_groups	= mdev_dev_groups,
>> +	.supported_type_groups	= mdev_type_groups,
>> +	.create			= mbochs_create,
>> +	.remove			= mbochs_remove,
>> +	.device_ops		= &vfio_mdev_ops,
>> +};
>> +
>>   static const struct file_operations vd_fops = {
>>   	.owner		= THIS_MODULE,
>>   };
>> diff --git a/samples/vfio-mdev/mdpy.c b/samples/vfio-mdev/mdpy.c
>> index d3029dd27d91..4ba285a5768f 100644
>> --- a/samples/vfio-mdev/mdpy.c
>> +++ b/samples/vfio-mdev/mdpy.c
>> @@ -725,12 +725,7 @@ static struct attribute_group *mdev_type_groups[]
>> = {
>>   	NULL,
>>   };
>>
>> -static const struct mdev_parent_ops mdev_fops = {
>> -	.owner			= THIS_MODULE,
>> -	.mdev_attr_groups	= mdev_dev_groups,
>> -	.supported_type_groups	= mdev_type_groups,
>> -	.create			= mdpy_create,
>> -	.remove			= mdpy_remove,
>> +static const struct vfio_mdev_parent_ops vfio_mdev_ops = {
>>   	.open			= mdpy_open,
>>   	.release		= mdpy_close,
>>   	.read			= mdpy_read,
>> @@ -739,6 +734,15 @@ static const struct mdev_parent_ops mdev_fops =
>> {
>>   	.mmap			= mdpy_mmap,
>>   };
>>
>> +static const struct mdev_parent_ops mdev_fops = {
>> +	.owner			= THIS_MODULE,
>> +	.mdev_attr_groups	= mdev_dev_groups,
>> +	.supported_type_groups	= mdev_type_groups,
>> +	.create			= mdpy_create,
>> +	.remove			= mdpy_remove,
>> +	.device_ops		= &vfio_mdev_ops,
>> +};
>> +
>>   static const struct file_operations vd_fops = {
>>   	.owner		= THIS_MODULE,
>>   };
>> diff --git a/samples/vfio-mdev/mtty.c b/samples/vfio-mdev/mtty.c
>> index 744c88a6b22c..a468904ec626 100644
>> --- a/samples/vfio-mdev/mtty.c
>> +++ b/samples/vfio-mdev/mtty.c
>> @@ -1410,6 +1410,14 @@ static struct attribute_group
>> *mdev_type_groups[] = {
>>   	NULL,
>>   };
>>
>> +static const struct vfio_mdev_parent_ops vfio_mdev_ops = {
>> +	.open                   = mtty_open,
>> +	.release                = mtty_close,
>> +	.read                   = mtty_read,
>> +	.write                  = mtty_write,
>> +	.ioctl		        = mtty_ioctl,
>> +};
>> +
>>   static const struct mdev_parent_ops mdev_fops = {
>>   	.owner                  = THIS_MODULE,
>>   	.dev_attr_groups        = mtty_dev_groups,
>> @@ -1417,11 +1425,7 @@ static const struct mdev_parent_ops mdev_fops
>> = {
>>   	.supported_type_groups  = mdev_type_groups,
>>   	.create                 = mtty_create,
>>   	.remove			= mtty_remove,
>> -	.open                   = mtty_open,
>> -	.release                = mtty_close,
>> -	.read                   = mtty_read,
>> -	.write                  = mtty_write,
>> -	.ioctl		        = mtty_ioctl,
>> +	.device_ops             = &vfio_mdev_ops,
>>   };
>>
>>   static void mtty_device_release(struct device *dev)
>> --
>> 2.19.1
>>
>> _______________________________________________
>> Virtualization mailing list
>> Virtualization at lists.linux-foundation.org
>> https://lists.linuxfoundation.org/mailman/listinfo/virtualization


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