Spark

spark is a 64-bit bootloader for RISC-V, implementing the Limine Boot Protocol for both SBI and UEFI systems.

Building

spark uses a custom build tool called xtask which wraps cargo and controls the entire build process. To build the bootloader, simply run cargo xtask build [--release]. The final build artifacts will be output into the build/ directory.

For a full list of the available build options, run cargo xtask build --help.

Using the Bootloader

Currently spark is limited to reading from NVMe drives.

The easiest way to get up and running is using QEMU's vvfat driver to emulate a FAT filesystem from a directory on your host:

-device nvme,serial=deadbeff,drive=disk1
-drive id=disk1,format=raw,if=none,file=fat:rw:path/to/directory

Alternatively, you can create a disk image to use as the backing for the drive:

-device nvme,serial=deadbeff,drive=disk1
-drive id=disk1,format=raw,if=none,file=path/to/disk.img

Example

spark.cfg:

boot "my awesome kernel" {
    protocol = "limine";
    kernel-path = "boot:///boot/kernel.elf";
}

$ mkdir -p ./root
$ cp path/to/kernel.elf ./root/
$ cp path/to/spark.cfg  ./root/
$ qemu-system-riscv64 -machine virt -cpu rv64 \
    -kernel spark.bin \
    -device nvme,serial=deadbeff,drive=disk1 \
    -drive id=disk1,format=raw,if=none,file=./root

Running

To run it in a virtual machine make sure you have qemu installed Just use cargo xtask run If you encounter an error with qemu try running cargo xtask run -- -cpu rv64