- `cpus` (int) - The number of cpus to use for building the VM. Defaults to 1. - `memory` (int) - The amount of memory to use for building the VM in megabytes. Defaults to 512 megabytes. - `sound` (bool) - Specifies whether to enable the sound device when building the VM. Defaults to false. - `usb` (bool) - Specifies whether to enable the USB bus when building the VM. Defaults to false.