Fix 'PCI bug' issue

[ibaldin]

The problem of some PCI network cards not passing traffic sometimes appears to be related to trust setting on VF. This seems to fix:

sudo ip link set ens7f0 vf 13 trust [on|off]

https://docs.mellanox.com/pages/viewpage.action?pageId=19798214#SingleRootIOVirtualizationSRIOV-PrivilegedVFs

It seems the handler should 'toggle' trust on, then off from DOM0 to make sure the VF works properly.

It is not clear if this can be done prior or after the VF is attached to the VM.

This issue likely should be moved to AMHandlers repo.

[kthare10]

For AMHandler to toggle the trust for VFs, following information is needed:

• Interface name on the Worker Node corresponding to Shared NIC [Question: Can the ARM include either the mac address of the Shared NIC or the interface name??]

• VF Index [Question: Can this be assumed to be the index of the PCI address in the ARM??]

[disprosium8]

Related bug tracking issue https://esnet.atlassian.net/browse/FABD-593

This task might want to wait if the upcoming Mellanox firmware update resolves the issue at all sites.