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Rust Hypervisor Firmware

This repository contains a simple firmware that is designed to be launched from anything that supports loading ELF binaries and running them with the PVH booting standard

The purpose is to be able to use this firmware to be able to load a bootloader from within a disk image without requiring the use of a complex firmware such as TianoCore/edk2 and without requiring the VMM to reuse functionality used for booting the Linux kernel.

Currently it will directly load a kernel from a disk image that follows the Boot Loader Specification

There is also minimal EFI compatibility support allowing the boot of some images that use EFI (shim + GRUB2 as used by Ubuntu).

The firmware is primarily developed against Cloud Hypervisor but there is also support for using QEMU's PVH loader.

This project was originally developed using Firecracker however as it does not currently support resetting the virtio block device it is not possible to boot all the way into the OS.

Building

To compile:

cargo build --release --target target.json -Zbuild-std=core,alloc -Zbuild-std-features=compiler-builtins-mem

The result will be in:

target/target/release/hypervisor-fw

Features

  • virtio (PCI) block support
  • GPT parsing (to find EFI system partition)
  • FAT12/16/32 directory traversal and file reading
  • bzImage loader
  • "Boot Loader Specification" parser
  • PE32+ loader
  • Minimal EFI environment (sufficient to boot shim + GRUB2 as used by Ubuntu)

Running

Works with Cloud Hypervisor and QEMU via their PVH loaders as an alternative to the Linux kernel.

Cloud Hypervisor and QEMU are currently the primary development targets for the firmware although support for other VMMs will be considered.

Cloud Hypervisor

As per getting started

However instead of using the binary firmware for the parameter to --kernel instead use the binary you build above.

$ pushd $CLOUDH
$ sudo setcap cap_net_admin+ep ./cloud-hypervisor/target/release/cloud-hypervisor
$ ./cloud-hypervisor/target/release/cloud-hypervisor \
	--kernel ./target/target/release/hypervisor-fw \
	--disk path=focal-server-cloudimg-amd64.raw \
	--cpus boot=4 \
	--memory size=512M \
	--net "tap=,mac=,ip=,mask=" \
	--rng
$ popd

QEMU

Use the QEMU -kernel parameter to specify the path to the firmware.

e.g.

$ qemu-system-x86_64 -machine q35,accel=kvm -cpu host,-vmx -m 1G\
    -kernel ./target/target/release/hypervisor-fw \
    -display none -nodefaults \
    -serial stdio \
    -drive id=os,file=focal-server-cloudimg-amd64.raw,if=none \
    -device virtio-blk-pci,drive=os,disable-legacy=on

Testing

"cargo test" needs disk images from make-test-disks.sh

And clear-28660-kvm.img:

https://download.clearlinux.org/releases/28660/clear/clear-28660-kvm.img.xz

sha1sum: 5fc086643dea4b20c59a795a262e0d2400fab15f

Security issues

Please use the GitHub security advisories feature for reporting issues: https://github.com/cloud-hypervisor/rust-hypervisor-firmware/security/advisories/new