hi, i would like to implement a PCIe to PCIe bridge (ArriaV GX) between 2 Hosts (both Root Complex).

The PCIe subsystem does not have a Bridge unlike its predecessors the PCI bus. PCIe devices are of 3 types only - Root Complex (RC), Switch (SW) and EndPoint( EP). The RC is the only initiator in this subsystem , while the Switch behaves like a routing mechanism that routes TLPs to devices (EP) on the downlink. EndPoints are typically implemented in devices such as Ethernet, SoundCards, etc..

In the PCIe subsystem there is no need for a Bridge as the PCIe subsystem can be expanded to support more devices (EPs) using a Switch.

For point to point communication, you can use one PCIe RP on one FPGA board, and a PCIe EP on another FPGA .

Two host PCIe RPs will not be able to talk to each other. A PCIe RP has to connect to a PCIe EP or SW downlink and uplink.