Abstract: Building a system-level prototype platform with FPGAs for hardware-software integration of one processor design under test (DUT) is an essential step in pre-silicon evaluations of the processor chip design. In order to meet design requirements of open-source processors based on the emerging open RISC-V instruction set architecture with minimized FPGA development efforts, we propose a system-level platform with a tightly-coupled SoC-FPGA chip for agile hardware-software integration and evaluation of RISC-V DUT processors. In specific, we first elaborate the interconnect between the DUT and the SoC via the existing SoC-FPGA interfaces. Then we introduce a scheme of virtual inter-processor interrupt to support highly-efficient collaboration between the DUT and the hardcore ARM processor in the SoC-FPGA. As a result, the DUT is able to flexibly leverage various I/O peripherals for full-system evaluation. The hardcore ARM processor is also involved for acceleration of the DUT's time-consuming software workloads. Additionally, we build a configurable framework on cloud for flexible composition and system integration of the DUT's hardware and software components. Based on our evaluation results with a couple of target RISC-V processors, we believe that our proposed platform is of great significance in improving efficiency and shortening iteration period when building a system-level prototype platform.