Re: qemu arguments

Hi Pavel, Thank you! I did not see that page before, I must admit. It's going to be of a great help! Have a good day, Pierre ----- Mail original ----- > On Tue, Feb 06, 2024 at 01:57:39PM +0100, Pierre Clouzet wrote: >> 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? > > Hi, > > I see that the wiki page doesn't cover memory-backend-ram but it is > implemented in libvirt and doable with XML. That wiki page will most > likely miss other QEMU commands but you can always check the Domain XML > format documentation [1] to see if libvirt supports what you want to > achieve. > > For your case you want to use something like this: > > <domain> > <currentMemory unit='GiB'>6</currentMemory> > <vcpu>8</vcpu> > ... > <cpu> > ... > <numa> > <cell id='0' cpus='0-3' memory='4' unit='GiB'/> > <cell id='1' cpus='4-7' memory='2' unit='GiB'/> > </numa> > ... > </domain> > > More details here [2]. > > Note: one defined libvirt will show the memory in `KiB` so that > behavior is expected. > > Pavel > > [1] <https://libvirt.org/formatdomain.html> > [2] <https://libvirt.org/formatdomain.html#cpu-model-and-topology>