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

> From: Jason Wang <jasowang@redhat.com>
> Sent: Thursday, 15 September 2022 11:51
> To: mst@redhat.com; jasowang@redhat.com
> Cc: Eli Cohen <elic@nvidia.com>; si-wei.liu@oracle.com; Parav Pandit
> <parav@nvidia.com>; wuzongyong@linux.alibaba.com;
> virtualization@lists.linux-foundation.org; linux-kernel@vger.kernel.org;
> eperezma@redhat.com; lingshan.zhu@intel.com; gdawar@xilinx.com;
> lulu@redhat.com; xieyongji@bytedance.com
> 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@redhat.com>
> ---
>  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@nvidia.com>

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