How to use Windows 10 OEM license in libvirt VM (<smbios mode='host' /> does not work as Windows seems to verify UUID; apparmor/security configuration changes may be needed)

domain.xml

<domain type='kvm' xmlns:qemu='http://libvirt.org/schemas/domain/qemu/1.0'>
  <!-- ... -->
  <qemu:commandline>
    <qemu:arg value='-acpitable'/>
    <qemu:arg value='file=/some/path/slic.bin'/>
    <qemu:arg value='-acpitable'/>
    <qemu:arg value='file=/some/path/msdm.bin'/>
    <qemu:arg value='-smbios'/>
    <qemu:arg value='file=/some/path/smbios_type_0.bin'/>
    <qemu:arg value='-smbios'/>
    <qemu:arg value='file=/some/path/smbios_type_1.bin'/>
  </qemu:commandline>
</domain>

slic-dump

#!/bin/bash

set -e

cat /sys/firmware/acpi/tables/SLIC > slic.bin
cat /sys/firmware/acpi/tables/MSDM > msdm.bin
dmidecode -t 0 -u | grep $'^\t\t[^"]' | xargs -n1 | perl -lne 'printf "%c", hex($_)' > smbios_type_0.bin
dmidecode -t 1 -u | grep $'^\t\t[^"]' | xargs -n1 | perl -lne 'printf "%c", hex($_)' > smbios_type_1.bin

If you're using virt-manager and the configuration is not applying, or if you then drop down to virsh and it fails with:

$ virsh -c qemu:///system edit win11
error: XML document failed to validate against schema: Unable to validate doc against /usr/share/libvirt/schemas/domain.rng
Element domain has extra content: qemu:commandline

Failed. Try again? [y,n,i,f,?]: 

keep in mind that the xmlns:qemu='http://libvirt.org/schemas/domain/qemu/1.0' at the root of the configuration is not fluff and is likely missing from yours. After I added this manually and booted the VM, Windows 11 activated for me.