这是一个 fork 自官方 xv6-riscv 的我的改进版，想了解更多关于改进的请移步我的博客
运行之前请把 "README.md" 重命名为 "README"
You will need a RISC-V "newlib" tool chain from https://github.com/riscv/riscv-gnu-toolchain, and qemu compiled for riscv64-softmmu. Once they are installed, and in your shell search path, you should rename "README.md" to "README" firstly, then run "make qemu".