For AVMM Stratix 10 PCIe Hard IP+, the MSI/MSI-X interface needs access via tl_cfg, but this interface is now not available at the top level. However, you can still find this interface at a lower layer instance which is "intel_pcie_s10_avmm_bridge_512.sv". I will feedback this to the Intel PSG engineering team to export those signals to the top level so that the user can access it directly without any manual modification.
Just for your information, the Intel PSG engineering team is in progress to enhance the IP to address this concern in the future IP release.
This problem is planned to fix in the next Quartus release version, where the tl_cfg interface will be exported by default from the IP at the top layer.
If further support is needed in this thread, please post a response within 15 days. After 15 days, this thread will be transitioned to community support. The community users will be able to help you with your follow-up questions.