Good news...:)
I was in vacation in last week.
I'm also install ethernet driver on my VPI system and did a simple test to connect to my 10Gb DCBX ethernet switch via Mellanox QSA converter. All of test was well done.
But my SuperMicro System doesn't have "above 4G decoding" in system BIOS.
But your description was very informative for me.
Have a nice day...:)