QEMU: NVIDIA Tesla M40 passthrough above 4G decoding

So, my issue is related to the Telsa PCi Barspace. The default in tianocore is to small.
Nvidia specifies MMIOH Base = 256G; MMIO High Size 128g and above 4g decoding
So I had a look a tianocore:

My question is: is there an easier way to solve this issue, or do I have to compile my own?