# Optimized, libvirt-compatible definitions for common OS ## Goal This repository's goal is to maintain definitions that are tuned for running modern, GUI-driven guest operating systems (OS), easing their installation on hosts that leverage KVM, such as [Phyllome OS](https://phyllo.me/). There are two kinds of definition for QEMU: **session-driven** virtual machines, and **system-driven** virtual machines. System-driven virtual machines are running with higher privileges. If one intend to share a physical device with a virtual machine using VFIO passthrough, this is the definition to use. More information [here](https://blog.wikichoon.com/2016/01/qemusystem-vs-qemusession.html). ## Usage ### Requirements It is expected that libvirt and other dependencies such as QEMU or the Cloud Hypervisor are already installed and correctly configured. * At least `QEMU` emulator version 7.0.0 * At least `libvirt` 8.6.0 * [Netboot.xyz](https://netboot.xyz/) ISO file under `/var/lib/libvirt/isos` ### How to use it * Download `Netboot.xyz.iso` file ``` # wget https://boot.netboot.xyz/ipxe/netboot.xyz.iso -P /var/lib/libvirt/isos/ ``` * Clone this repository * Navigate to the *session* directory * Choose your target OS of choice and, as a normal user, use the following `virsh` command to create a virtual machine using the `define` argument: ``` $ virsh define linux54.xml Domain 'Linux5.4' defined from linux54.xml ``` * List the newly-created virtual machine ``` $ virsh list --all Id Name State ------------------------ - Linux5.4 shut off ``` * Delete the virtual machine usine the `undefine` argument ``` $ virsh undefine Linux5.4 Domain 'Linux' has been undefined ``` ### System-driven virtual machines * Navigate to the *system* directory * Choose your target OS of choice and, as a root user, use the following `virsh` command to define a virtual machine: ``` # virsh define linux54.xml Domain 'Linux5.4' defined from linux54.xml ``` ``` # virsh list --all Id Name State ------------------------ - Linux5.4 shut off ``` * Delete it ``` # virsh undefine Linux5.4 Domain 'Linux5.4' has been undefined ``` ## Status | | Linux 5.4 | Linux 5.15 | Windows 10 | Windows 11 | | --- | --- | --- | --- | --- | | *Chipset* | `Q35` | `Q35` | `Q35` | `Q35` | | *Platform Firmware* | `OVMF` | `OVMF` | `OVMF` | `OVMF` | | *Secure boot* | No | No | No | **Yes** | | *[Netboot.xyz](https://netboot.xyz/) ISO loaded* | **Yes** | **Yes** | **Yes** | No | | *`Spice display`* | **Yes**, with 3D accel. | **Yes**, with 3D accel. | **Yes**, without 3D accel. | **Yes**, without 3D accel. | | *`virtio-gpu`* | **Yes**, with 3D accel. | **Yes**, with 3D accel. | **Yes**, without 3D accel. | **Yes**, without 3D accel. | | *`virtio-blk`* | Not applicable | Not applicable | Not applicable | Not applicable | | *`virtio-scsi`* | **Yes** | **Yes** | **Yes** | **Yes** | | *`virtio-fs`* | **Yes**, for System-driven VM | **Yes**, for System-driven VM | **Yes** | **Yes** | | *`virtio-net`* | **Yes** | **Yes** | **Yes** | **Yes** | | *`virtio-keyboard`* | **Yes** | **Yes** | **Yes** | **Yes** | | *`virtio-tablet`* | **Yes** | **Yes** | **Yes** | **Yes** | | *`virtio-iommu`* | No | **Yes** | No | No | More information [here](https://wiki.phyllo.me/e/en/virt/guest) on the status for virtio support on guest operating systems. ## Context [Libvirt](https://libvirt.org/) is the most popular virtualization library on Linux, and it is central to Phyllome OS. Libvirt uses an XML file to store the definition of a virtual machine, including its firmware (e.g. BIOS or UEFI-based), the size of its memory, the nature of a particular device (e.g. virtio or emulated hardware), etc. ### Why [The reference Domain XML format webpage](https://libvirt.org/formatdomain.html), which is almost 100 pages long, lists most of the accepted parameters that can be used to define a virtual machine. Picking the most optimized parameters for running a particular guest OS is a complicated task. This project intends to find the best parameters for the most popular OS. ### Assomptions The best parameters are defined as parameters that are: - Performance-oriented, providing good out-of-the-box performance. - Relatively host-agnostic, so that a virtual machine could be migrated to another host. - Modern, leveraging as many paravirtualized devices (a.k.a virtio devices) the target guest OS can support, with the intend to become usable with modern virtualization solution such as the Cloud Hypervisor. ## Resources * Domain XML format for libvirt: https://libvirt.org/formatdomain.html * qemu:///system vs qemu:///session, a great article by Cole Robinson: https://blog.wikichoon.com/2016/01/qemusystem-vs-qemusession.html