attach a pcie root port as hostdev

Hello community, I am working on plugging a xilinx fpga card as a hostdev. This fpga card has 2 functions, each has a different role, for some reason, I would like to attach both of them but do not want to attach them separately, so I have tried to attach a pci bridge where fpga cards connect to. but got the following error, error: Failed to attach device from bridge.xml error: internal error: Non-endpoint PCI devices cannot be assigned to guests so, my question is is it possible to attach a pci-bridge as hostdev? thank you. -- Best Regards, Jiatong Shen