Has anyone here looked at https://github.com/alexforencich/cocotbext-pcie ?

Nice! I am currently working on an LVDS-Transciever and if that project is finished, then modifications to the design are quite to implement pcie... Nice... Ive already seen, that other people had written pcie ip cores for it (in this case primarly for FPGAs) ... Integration of all the projects should be quite straight forward then