could anyone give me a hint which tool to use to test basic RDMA/RoCE connectivity between WIndows and Linux hosts?
try "Win-Linux nd_rping" test tool
it should check interoperability between Linux and Windows via an RDMA connection
Assuming you've installed WinOF/WinOF-2 - use the built-in nd_rping.exe tool
On Windows server -go to: Program Files\Mellanox\MLNX_VPI\IB\Tools and use nd_rping.exe (-h will give you the options)
On Linux server - install that will provide you the "rping.exe" application.