I afraid I don't recall the status of DSP blocks in the open source toolchains for Xilinx hardware. Even if the basics are supported I'm sure there are plenty of DSP features that are not.
Many configurations of VexRISCV work fine without using the DSP blocks (and has been working for 2+ years), so not sure that is relevant.
Many configurations of VexRISCV work fine without using the DSP blocks (and has been working for 2+ years), so not sure that is relevant.