PCI passthrough SRIOV support

Requements from SRIOV

• group device

  for SRIOV, all VFs belong to same PF share same physical network reachability. so if you want, say, deploy a vlan network, you need choose the right PF's VF, otherwise network does not work for you.

• tracking device alloced to the NIC

  networking or other special deive is not as simple as pass though to the VM, there is need more configration. to acheive this, SRIOV must know the device infomation allocation to the specific NIC.

Solution: group the devices

    whitlist or a seperated config option use a (k,v) in extra info as group defination. enable BDF as group spec. 
    alias should enable to use extra_info as part of spec, so user can allocation from the group.
    pci_stats should support group as part of summary infomation.

solution: tracking device allocated to alias

use request append infomation to alloced device then find if by (k,v)