XDP-ZC RSS - Mellanox

Hello XDP-newbies,
i am trying to figure it out, how can i configure Mellanox mlx5 card to 
use XSK(XDP)-ZeroCopy queues instead of normal RX queues and use RSS to 
spread traffic.

I have no issue with this on Intel Cards which use same queue for 
both(normal and ZC mode).

My commands for Intel:
$ sudo ethtool -L ens4f0 combined 8
$ sudo ethtool -N ens4f0 rx-flow-hash udp4 fn
$ sudo ethtool -X ens4f0 equal 8 start 0
$ sudo ./xdpsock -q 0 -z // everything is OK


My commands for Mellanox:
$ sudo ethtool -L ens4f0 combined 8
$ sudo ethtool -l ens4f0
Channel parameters for ens4f0:
Current hardware settings:
RX:             n/a
TX:             n/a
Other:          0
Combined:       8

// Bind to ZeroCopy queue 8, after bind number of combined queues 
doubled. [0..N-1 (normal RX queues), N..(2N-1) (ZeroCopy queues)]
$ sudo ./xdpsock -i ens4f0 -q 8 -z &
$ sudo ethtool -l ens4f0
Channel parameters for ens4f0:
Current hardware settings:
RX:             n/a
TX:             n/a
Other:          0
Combined:       16

// Try to redirect traffic to ZeroCopy queue 8-15
$ sudo ethtool -X ens4f0 start 8 equal 8
Cannot set RX flow hash configuration: Invalid argument


The only solutions that i found was to use "flow steering rules" to 
redirect traffic to specific ZeroCopy queue, but this does not solve my 
issue.

Is there any way how to achieve my goal on Mellanox card?
(mlx5_core v. 5.5-1.0.3, ol8 kernel 4.18)


Thanks,
Pavel Siska