[libvirt] Adding switchdev NIC capability to nodedev

[Edan David]

Hi,

We want to add functionality to Libvirt that will allow querying the interface for the availability of switchdev  mode (Offloading NIC capability)
The switchdev mode was introduced in kernel 4.8, the iproute2-devlink command to retrieve the swtichdev NIC feature
Command example:  devlink dev eswitch show pci/0000:03:00.0
This feature is needed for Openstack so we can do a scheduling decision if the NIC is in Hardware Offload (switchdev) or regular SR-IOV (legacy) mode.
And select the appropriate hypervisors with the requested capability see [1]. 
We also Opened Bugzilla for this [1] 
A patch for the feature will be submitted shortly. 

[1] - https://specs.openstack.org/openstack/nova-specs/specs/pike/approved/enable-sriov-nic-features.html 
[2] - https://bugzilla.redhat.com/show_bug.cgi?id=1469552