RVVM - The RISC-V Virtual Machine

RISC-V CPU & System software implementation written in С

What's working

• Passes RISC-V compliance tests for both RV64 & RV32
• OpenSBI, U-Boot, custom firmwares boot and execute properly
• Linux kernel boots!
• Linux userspace works, interactive shell through UART
• Framebuffer graphics, working Xorg with mouse & keyboard
• Raw image mounted as rootfs

What's done so far

• Feature-complete RV64IMAFDC instruction set
• Multicore support (SMP)
• Bootrom, kernel Image loading
• DTB auto-generation, passing to firmware/kernel
• RVVM Lib API for VM integration
• MMU with SV32/SV39/SV48/SV57 virtual addressing
• UART 16550a-compatible text console
• PLIC/CLIC, timers
• PS2 Altera Controller, PS2 keyboard & mouse
• Graphical framebuffer through X11/WinAPI
• Generic PCI Bus
• ATA PIO hard drive
• ATA BMDMA (IDE UDMA) over PCI
• OpenCores Ethernet through Linux TAP
• Poweroff/reset device

Building

Currently builds using GNU Make or CMake and tested on Linux, Windows and MacOS systems. More build targets are going to be supported.

git clone https://github.com/LekKit/RVVM
cd RVVM
make
cd release.linux.x86_64

To cross-compile, pass CC=target-gcc and OS=target-os if the target OS differs from your host to make. You can configure the build with use flags

Examples:

make CC=x86_64-w64-mingw32-gcc OS=windows USE_JIT=1
make CC=aarch64-linux-gnu-gcc OS=linux USE_FB=0 USE_NET=1 USE_JIT=0

Alternatively, you can use CMake (hint, build binaries are not host arch suffixed):

git clone https://github.com/LekKit/RVVM
cd RVVM
mkdir build
cmake -S. -Bbuild
cmake --build build --target all
cd build

Running

./rvvm_x86_64 fw_jump.bin -kernel linux_Image -image rootfs.img -rv64 -mem 2G -smp 2 -res 1280x720

Argument explanation:

fw_jump.bin            Initial firmware, OpenSBI in this case
-kernel linux_Image    Kernel Image to be booted by SBI, etc
-image rootfs.img      Hard drive image to be mounted as rootfs
-rv64                  Enable RV64, RV32 is used by default
-mem 2G                Memory amount (may be suffixed by k/M/G), default 256M
-smp 2                 Amount of cores, single-core machine by default
-res 1280x720          Changes framebuffer & VM window resolution

Invoke "./rvvm_x86_64 -h" to see extended help.

Our team

• LekKit: RVVM API, interpreter, RV64IMAC ISA, RISC-V Hart/MMU/Privileged/CSR, codebase infrastructure, working on JIT
• cerg2010cerg2010: Important fixes, initial RV64 work, PLIC/PS2/ATA/Ethernet, XCB window backend, FPU extensions, FDT lib, working on PCI
• Mr0maks: Initial ideas, C/M extensions, VM debugger, CSR work, NS16550A UART
• Hoping to see more contributors here

TODO

• Test FreeBSD, HaikuOS (FreeBSD generic kernel boots but i have no idea how to mount rootfs, too lazy to look at Haiku)
• Improve RVVM Lib public API
• Working JIT infrastructure (many headaches from x86 backend)
• SATA/SCSI
• Sparse HDD image format, compression
• Userspace networking, sound?
• Maybe virtio devices
• Other peripherals
• A lot more...
• Userspace emulation?