qemu arguments

Hello, I've recently tried libvirt api to manage virtual machine. The point of my work is to modify the topology of a virtual machine and test performances (add numa nodes, change number of cpu per numa, nvm devices, cxl, etc) As far as understand, when using virt-manager, qemu arguments stored in xml files can only be like the one that page: [ https://wiki.libvirt.org/QEMUSwitchToLibvirt.html | https://wiki.libvirt.org/QEMUSwitchToLibvirt.html ] But maybe I misundertood? For example, when I directly run qemu with arguments, I can add an arguments like this: qemu [...] -object memory-backend-ram,size=4G,id=ram0 -object memory-backend-ram,size=2G,id=ram1 -numa node,nodeid=0,memdev=ram0,cpus=0-3 -numa node,nodeid=1,memdev=ram1,cpus=4-7 To have 2 numa nodes with 4 cpus each. Is there an equivalent of -objet, -numa, -device; qemu arguments when using libvirt? Or arguments are restricted to the one described on wiki page? Thanks for you help, Have a good day, Pierre Clouzet