Virtualization - Mar 2022 - [PATCH v2 1/2] vdpa: support exposing the config size to userspace

? 2022/3/10 ??3:20, Longpeng(Mike) ??:
> From: Longpeng <longpeng2 at huawei.com>
>
> - GET_CONFIG_SIZE: return the size of the virtio config space.
>
> The size contains the fields which are conditional on feature
> bits.
>
> Signed-off-by: Longpeng <longpeng2 at huawei.com>

Acked-by: Jason Wang <jasowang at redhat.com>

> ---
>   drivers/vhost/vdpa.c       | 17 +++++++++++++++++
>   include/linux/vdpa.h       |  3 ++-
>   include/uapi/linux/vhost.h |  4 ++++
>   3 files changed, 23 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
> index ec5249e..605c7ae 100644
> --- a/drivers/vhost/vdpa.c
> +++ b/drivers/vhost/vdpa.c
> @@ -355,6 +355,20 @@ static long vhost_vdpa_get_iova_range(struct
vhost_vdpa *v, u32 __user *argp)
>   	return 0;
>   }
>   
> +static long vhost_vdpa_get_config_size(struct vhost_vdpa *v, u32 __user
*argp)
> +{
> +	struct vdpa_device *vdpa = v->vdpa;
> +	const struct vdpa_config_ops *ops = vdpa->config;
> +	u32 size;
> +
> +	size = ops->get_config_size(vdpa);
> +
> +	if (copy_to_user(argp, &size, sizeof(size)))
> +		return -EFAULT;
> +
> +	return 0;
> +}
> +
>   static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int
cmd,
>   				   void __user *argp)
>   {
> @@ -492,6 +506,9 @@ static long vhost_vdpa_unlocked_ioctl(struct file
*filep,
>   	case VHOST_VDPA_GET_IOVA_RANGE:
>   		r = vhost_vdpa_get_iova_range(v, argp);
>   		break;
> +	case VHOST_VDPA_GET_CONFIG_SIZE:
> +		r = vhost_vdpa_get_config_size(v, argp);
> +		break;
>   	default:
>   		r = vhost_dev_ioctl(&v->vdev, cmd, argp);
>   		if (r == -ENOIOCTLCMD)
> diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h
> index 721089b..a526919 100644
> --- a/include/linux/vdpa.h
> +++ b/include/linux/vdpa.h
> @@ -207,7 +207,8 @@ struct vdpa_map_file {
>    * @reset:			Reset device
>    *				@vdev: vdpa device
>    *				Returns integer: success (0) or error (< 0)
> - * @get_config_size:		Get the size of the configuration space
> + * @get_config_size:		Get the size of the configuration space includes
> + *				fields that are conditional on feature bits.
>    *				@vdev: vdpa device
>    *				Returns size_t: configuration size
>    * @get_config:			Read from device specific configuration space
> diff --git a/include/uapi/linux/vhost.h b/include/uapi/linux/vhost.h
> index c998860..bc74e95 100644
> --- a/include/uapi/linux/vhost.h
> +++ b/include/uapi/linux/vhost.h
> @@ -150,4 +150,8 @@
>   /* Get the valid iova range */
>   #define VHOST_VDPA_GET_IOVA_RANGE	_IOR(VHOST_VIRTIO, 0x78, \
>   					     struct vhost_vdpa_iova_range)
> +
> +/* Get the config size */
> +#define VHOST_VDPA_GET_CONFIG_SIZE	_IOR(VHOST_VIRTIO, 0x79, __u32)
> +
>   #endif