Thanks for getting back to me..
I would like to have multiple VLANs with each VLAN having their own QoSs inside VM. It would be nice to configure everthing inside the guest instead of doing anything at host at all. But I am okay with setting VLAN to QoS mappings in Host and send traffic with VLAN tags from inside VM and get the traffic throttled according to host settings.
We are not using RoCE.
I tried both VST and VGT:
VGT: With VGT, the problem I am facing is inside VM, I created vlan devices using vconfig and send traffic and the rate limit I get is that of VLAN0 on host. So configuring VLAN inside VM is not working. So rate limit of VLAN0 on host is all I can get.
VST: With VST, creating more than one VF(with each VFs having their own VLAN/QoS set on host) as you said, but that would complicate our design a bit and we are trying to keep it as the last resort.
If I could use VGT with multiple VLANs inside VM and get rate control that would be the ultimate thing I'm looking for.
Note: Documentation(Mellanox_OFED_Linux_User_Manual_v2.2-1.0.1.pdf) says VGT is default behaviour.