GitLab

Add netlink attribute to store the negotiated features. This can be used
by userspace to get the current state of the vdpa instance.

Examples:

$ vdpa dev config show vdpa-a
vdpa-a: mac 00:00:00:00:88:88 link up link_announce false max_vq_pairs 16 mtu 1500
  negotiated_features CSUM GUEST_CSUM MTU MAC HOST_TSO4 HOST_TSO6 STATUS \
  CTRL_VQ MQ CTRL_MAC_ADDR VERSION_1 ACCESS_PLATFORM

$ vdpa -j dev config show vdpa-a
{"config":{"vdpa-a":{"mac":"00:00:00:00:88:88","link ":"up","link_announce":false, \
 "max_vq_pairs":16,"mtu":1500,"negotiated_features":["CSUM","GUEST_CSUM","MTU","MAC", \
 "HOST_TSO4","HOST_TSO6","STATUS","CTRL_VQ","MQ","CTRL_MAC_ADDR","VERSION_1", \
 "ACCESS_PLATFORM"]}}}

$ vdpa -jp dev config show vdpa-a
{
    "config": {
        "vdpa-a": {
            "mac": "00:00:00:00:88:88",
            "link ": "up",
            "link_announce ": false,
            "max_vq_pairs": 16,
            "mtu": 1500,
            "negotiated_features": [
"CSUM","GUEST_CSUM","MTU","MAC","HOST_TSO4","HOST_TSO6","STATUS","CTRL_VQ","MQ", \
"CTRL_MAC_ADDR","VERSION_1","ACCESS_PLATFORM"
]
        }
    }
}
Signed-off-by: Eli Cohen <elic@nvidia.com>
Link: https://lore.kernel.org/r/20220105114646.577224-9-elic@nvidia.com

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>