In addition to the IP catalog in the Vivado design tools, the 40G/50G Ethernet Subsystem can be requested for a specific configuration using a customer-provided spreadsheet. You must submit the completed spreadsheet to AMD Technical Support to obtain the target netlist. See Synthesis and Implementation for a description of what is delivered and how to proceed with the deliverables.
For a complete understanding of the core, consult the document corresponding to the core and the device selected, such as the UltraScale Architecture GTH Transceivers User Guide (UG576).