This excellent Hackaday Supercon keynote by Megan Wachs of SiFive gives a great introduction to two exciting topics:
The software world has fully embraced open source as a way to move forward together, faster. The hardware world is rapidly catching up, but until recently, one building block was still proprietary: the CPU’s Instruction Set Architecture, or ISA. The ISA is the language that the computer speaks, and aligning on a common language enables both open hardware implementations and collaboration on software tools. RISC-V is a free and open ISA which is revolutionizing both academic research and the semiconductor industry. In my talk I will give an intro to RISC-V and explain how it is enabling a new level of hardware hacking, on FPGAs and beyond.