wiki/virt/vm.md

title, description, published, date, tags, editor, dateCreated

title	description	published	date	tags	editor	dateCreated
Machine definition	Virtual machine hardware	true	2025-06-01T17:37:29.262Z		markdown	2025-06-01T17:37:29.262Z

Virtual machine hardware

Libvirt uses XML files to define virtual machine hardware.

In the context of libvirt, a virtual machine or guest system is called a domain. In turn, a domain type refers to the hypervisor used for running the virtual machine.

The following command output the XML description of the domain called phyllomeos

virsh dumpxml phyllomeos

<domain type='kvm'>
  [...]
</domain>

Domain type

At the moment, Phyllome OS focuses solely on hardware-assisted virtualization with KVM and QEMU. Therefore, the domain type KVM is the one used by default.

<domain type='kvm'>
  [...]
</domain>

Not all QEMU commands are supported by Libvirt. To pass QEMU commands, one need to use the following instead and add the QEMU command line at the end :

<domain type='kvm' xmlns:qemu='http://libvirt.org/schemas/domain/qemu/1.0'>
	[...]
  <qemu:commandline>
    <qemu:arg value='-device'/>
    <qemu:arg value='ipmi-bmc-sim,id=bmc0'/>
    <qemu:arg value='-device'/>
    <qemu:arg value='smbus-impi,bmc=bmc0'/>
    <qemu:env name='QEMU_MODULE_DIR' value='/usr/lib64/qemu'/>
  </qemu:commandline>
</domain>

If QEMU command lines are not immediately provided, it will automatically revert to simply <domain type='kvm'> upon writing changes to the domain {.is-info}

Under QEMU, the said domain definition translates to:

qemu-system-x86_64 -enable-kvm [...]