sovos

An x86-64 kernel written in Rust

Dependencies

This project is as dependency-free as possible. Nightly Rust is a must (it rhymes, lol), miri and clippy might be useful for dev purposes.

Building

Currently, for building you would only need uart_16550 and arrayvec.

Running

For running, it needs qemu-system-x86_64 and UEFI image under /usr/share/edk2/ovmf/OVMF_CODE.fd

Commands

Building

Just cargo xtask build! It creates a directory named fat/, that is later attached to QEMU.

Running

Running is also simple, cargo xtask run. QEMU is started with -nographic mode and serial output is directed to stdout. If you want to attach GDB to the VM (-s and -S), you would need to uncomment additional parameters in xtask/src/main.rs

It is possible to copy the contents of fat/ directory into a real FAT32 drive and run it on real hardware with UEFI, but there are currently no guarantees that it will work (mostly because serial port is hardcoded to 0x3F8 and EFI text protocols usage is limited as for now)

Cleaning

To remove all the artifacts, run cargo xtask clean all

Structure

• kernel/ contains, well, the actual kernel code (work has not started there [YET!])
• uefi_wrapper/ is a thing that performs initial setup, gathers information about hardware, (will probably) decompress kernel binary and jump to it
• libs/ is anything that can be separated, reused or just requires testing that would otherwise be much harder to do under kernel environment
• xtask/ is the "script" that makes building and running easier

Inside those directories, there should recursively be readmes about useful stuff

Philosophy

There aren't many rules, just

• Take one detail from a problem and try to think about a good way to solve it
• Explore new ideas, don't restrict yourself to the known
• Think of scalability, if the solution could handle tens of cores, terabytes of memory, thousands of processes

Todolist (kinda?)

• Documentation
  • This readme
  • Document kernel/
  • Document libs/
  • Document libs/freetree
• Physical memory allocator
  • The POC is finished! (libs/freetree/src/poc.rs)
  • Work on "flavors" of the POC
  • Maybe we could write a parallel skiplist?
• uefi_wrapper
  • Use UEFI text protocol if possible before exiting boot services
  • Check CPU features and capabilities (we assume at least Sandybridge features, see kernel/README.md)
  • Figure out if it is possible to just load the kernel ELF into memory and jump into it
  • After writing a memory allocator, we could actually jump into kernel
• Virtual memory mapping
  • The basic structures for x64 are there, but I think I have an idea for a rewrite
• VirtIO
  • I'd like to work on network things first, to have a UDP or maybe even TCP stack to connect to instead of using serial port
  • Block devices
• Support for RISC-V
  • Support for Rv39, 48 and 57
  • Other things needed in libs/cpu
  • Idk, figure out what is needed to boot