vm-additions.xml

<domain xmlns:qemu='http://libvirt.org/schemas/domain/qemu/1.0' type='kvm'>

    <devices>
        <!-- Output using SPICE with MESA EGL  -->
        <graphics type="spice">
            <listen type="none"/>
            <gl enable="yes"/>
        </graphics>
        <video>
            <model type="none"/>
        </video>

        <!-- virtual GPU passthrough -->
        <hostdev mode='subsystem' type='mdev' managed='no' model='vfio-pci' display='on'>
            <source>
                <address uuid='1d7f1075-b787-4cbc-a48c-c91243c93224'/>
            </source>
        </hostdev>
    </devices>

    <!-- this goes at the bottom, before closing domain tag -->
    <qemu:override>
        <qemu:device alias="hostdev0">
            <qemu:frontend>
                <qemu:property name="romfile" type="string" value="/var/lib/libvirt/qemu/drivers/i915ovmf.rom"/> <!-- the rom we built goes here! -->
                <qemu:property name="x-igd-opregion" type="bool" value="true"/>
                <qemu:property name="driver" type="string" value="vfio-pci-nohotplug"/>
                <qemu:property name="ramfb" type="bool" value="true"/>
                <qemu:property name="xres" type="unsigned" value="1920"/> <!-- change resolution of the driver to what you want -->
                <qemu:property name="yres" type="unsigned" value="1080"/>
            </qemu:frontend>
        </qemu:device>
    </qemu:override>
</domain>