When the AXI4-Stream interface is enabled, each H2C streaming channels is looped back to C2H channel. As shown in the following figure, the example design gives a loopback design for AXI4 streaming. The limitation is that you need to select an equal number of H2C and C2H channels for proper operation. This example design also shows PCIe to DMA bypass interface and PCIe to AXI-Lite Master selected.
Figure 1. AXI4-Stream Example with PCIe to DMA Bypass Interface and PCIe to AXI-Lite Master Enabled