My interpretation of this:

You have an x86 machine running Linux v5.12 which is running QEMU using KVM accelerations. Using this setup, you're able to emulate a machine that can run Xen. Since Xen is a type 1 hypervisor, you would then run a Dom0 and perhaps many DomU machines inside it, let's say Linux here for both.

Hardware > Linux KVM > QEMU > Xen guest > Linux Dom0 guest, Linux DomU guest