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Experimental KVM-based type-2 hypervisor in Rust implemented from scratch.

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google/alioth

Alioth

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Alioth /AL-lee-oth/ is an experimental KVM-based type-2 hypervisor (virtual machine monitor) in Rust implemented from scratch.

Important

Disclaimer: Alioth is not an officially supported Google product.

Quick start

  • Install Alioth from source,

    cargo install alioth-cli --git https://github.com/google/alioth.git
  • Make an initramfs with u-root.

  • Boot a Linux kernel with 2 CPUs and 4 GiB memory,

    alioth -l info --log-to-file \
        run \
        --kernel /path/to/vmlinuz \
        --cmd-line "console=ttyS0" \
        --initramfs /path/to/initramfs \
        --memory size=4G \
        --num-cpu 2

Features

  • Runs on x86_64 and aarch64.
  • Boots confidential VMs with AMD SEV, SEV-ES, or SEV-SNP, see coco.md for details.
  • VirtIO devices
    • net backed by a tap device,
    • vsock backed by host /dev/vhost-vsock,
    • blk backed by a raw-formatted image,
    • entropy backed by host /dev/urandom,
    • fs backed by virtiofsd with experimental Direct Access (DAX),
    • (WIP) balloon with free page reporting.
  • PCI device passthrough based on VFIO/IOMMUFD.
  • Other devices
    • serial console: 16450 on x86_64, pl011 on aarch64,
    • fw_cfg (QEMU Firmware Configuration Device),
    • pvpanic.

TODOs

  • explore a better solution to ACPI DSDT to replace the pre-compiled AML bytes,
  • increase test coverage,
  • add missing documents,
  • (long term) port Alioth to Apple's Hypervisor framework,
  • performance, performance, and performance!

Acknowledgment

The virtualization implementation in Alioth takes the following projects as references,

The error handling practice is inspired by GreptimeDB's stack_trace_debug.