RE: [PATCH 1/3] vdpa: device feature provisioning

[Eli Cohen]

> From: Jason Wang <jasowang@xxxxxxxxxx>
> Sent: Thursday, 15 September 2022 11:51
> To: mst@xxxxxxxxxx; jasowang@xxxxxxxxxx
> Cc: Eli Cohen <elic@xxxxxxxxxx>; si-wei.liu@xxxxxxxxxx; Parav Pandit
> <parav@xxxxxxxxxx>; wuzongyong@xxxxxxxxxxxxxxxxx;
> virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> eperezma@xxxxxxxxxx; lingshan.zhu@xxxxxxxxx; gdawar@xxxxxxxxxx;
> lulu@xxxxxxxxxx; xieyongji@xxxxxxxxxxxxx
> Subject: [PATCH 1/3] vdpa: device feature provisioning
> 
> This patch allows the device features to be provisioned through
> netlink. A new attribute is introduced to allow the userspace to pass
> a 64bit device features during device adding.
> 
> This provides several advantages:
> 
> - Allow to provision a subset of the features to ease the cross vendor
>   live migration.
> - Better debug-ability for vDPA framework and parent.
> 
> Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
> ---
>  drivers/vdpa/vdpa.c       | 5 +++++
>  include/linux/vdpa.h      | 1 +
>  include/uapi/linux/vdpa.h | 2 ++
>  3 files changed, 8 insertions(+)
> 
> diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
> index c06c02704461..278e26bfa492 100644
> --- a/drivers/vdpa/vdpa.c
> +++ b/drivers/vdpa/vdpa.c
> @@ -600,6 +600,11 @@ static int vdpa_nl_cmd_dev_add_set_doit(struct
> sk_buff *skb, struct genl_info *i
>  		}
>  		config.mask |=
> BIT_ULL(VDPA_ATTR_DEV_NET_CFG_MAX_VQP);
>  	}
> +	if (nl_attrs[VDPA_ATTR_DEV_FEATURES]) {
> +		config.device_features =
> +			nla_get_u64(nl_attrs[VDPA_ATTR_DEV_FEATURES]);
> +		config.mask |= BIT_ULL(VDPA_ATTR_DEV_FEATURES);
> +	}
> 
>  	/* Skip checking capability if user didn't prefer to configure any
>  	 * device networking attributes. It is likely that user might have used
> diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h
> index d282f464d2f1..6d0f5e4e82c2 100644
> --- a/include/linux/vdpa.h
> +++ b/include/linux/vdpa.h
> @@ -104,6 +104,7 @@ struct vdpa_iova_range {
>  };
> 
>  struct vdpa_dev_set_config {
> +	u64 device_features;
>  	struct {
>  		u8 mac[ETH_ALEN];
>  		u16 mtu;
> diff --git a/include/uapi/linux/vdpa.h b/include/uapi/linux/vdpa.h
> index 25c55cab3d7c..9dc855f37c59 100644
> --- a/include/uapi/linux/vdpa.h
> +++ b/include/uapi/linux/vdpa.h
> @@ -52,6 +52,8 @@ enum vdpa_attr {
>  	VDPA_ATTR_DEV_VENDOR_ATTR_NAME,		/* string */
>  	VDPA_ATTR_DEV_VENDOR_ATTR_VALUE,        /* u64 */
> 
> +	VDPA_ATTR_DEV_FEATURES,                 /* u64 */

Maybe VDPA_ATTR_DEV_FEATURES_MASK would be more informative. Other than that:
Reviewed-by: Eli Cohen <elic@xxxxxxxxxx>

> +
>  	/* new attributes must be added above here */
>  	VDPA_ATTR_MAX,
>  };
> --
> 2.25.1