On 06/05/2012 04:42 AM, Yashwanth K P wrote: It would help if we knew more information about what you wanted. Are you asking for how to add an extra command line argument to qemu? If so, we already have a way to add custom arguments as an interim measure until official domain XML is enhanced to support the argument directly; see http://libvirt.org/drvqemu.html#qemucommand Also, knowing _what_ command line argument you are adding in the interim would help us know whether we need to focus on getting it into the official XML sooner rather than later. Are you asking for how to add arbitrary XML that does not affect the qemu command line generated by libvirt, but which lets you associate additional custom information with each domain? If so, libvirt already supports that via domain description (freeform) and metadata (xml namespace sub-elements); see http://libvirt.org/formatdomain.html#elementsMetadata Are you asking for how to extend the supported domain XML to code in a new feature? If so, it may help to browse existing commits that have added new XML. For example, commit 988e85a added a <codec> sub-element for controlling sound devices, followed by commit a7675a6 to wire up qemu to use that new XML. -- Eric Blake eblake(a)redhat.com +1-919-301-3266 Libvirt virtualization library http://libvirt.org