Hi Brian,
When using virtualization, GRH (global routing header) must be present in the packet. For ibping, --dgid <GID> parameter need to be used (see man ibping).
To get GIDs, on the server run 'show_gids' and use the output on the client side
Server
#show_gids
DEV PORT INDEX GID IPv4 VER DEV
--- ---- ----- --- ------------ --- ---
mlx5_1 1 0 fe80:0000:0000:0000:248a:0703:009c:01a7 v1
Client
#ibping --dgid fe80:0000:0000:0000:248a:0703:009c:01a7 18
If you like to check RDMA connectivity between VMs, use utilities from perftest package (ib_read_bw, ib_write_bw, etc) with -R parameter.