quoted

Right. Let me give it a try first with pseries Qemu. Otherwise I have an
access to pseries LPAR too. I can verify it there.

Ah, now I realize my problem: I tried with Fedora 43 in a powerpc VM but
the modprobe didn't do anything.

Looking again:

# grep CONFIG_CMM /boot/config-6.17.1-300.fc43.ppc64le
CONFIG_CMM=y

So modprob'ing won't do as the module is built in.

Right, so doing "cmm.simulate=1" on the cmdline in a Fedora 43 VMs 
properly creates the CMM device.

-- 
Cheers

David