We have come up with some ideas about improving the performance of virtual machines on the RISC-V architecture. Here’s the first piece which proposes a dedicated clock source and a clock event source for HS-mode and VS-mode,
respectively. We extended the current idea of the mtime and mtimecmp CSRs and combined with the current hypervisor extension to come up with new CSRs and aliases. Evaluations on QEMU show that the proposed extension leads to performance improvement.
The attached document details the proposal. Any comments are welcome.