Comment 4 for bug 2012028

The section created by jammy and lunar in regard to the tpm is the same in both cases:

    <tpm model="tpm-crb">
      <backend type="emulator"/>
    </tpm>

With that known here a minimal testcase:

# cat minimal.xml
<domain type="kvm">
  <name>minimal</name>
  <memory>2097152</memory>
  <features>
    <acpi/>
   </features>
  <os>
    <type arch="x86_64" machine="q35">hvm</type>
  </os>
  <devices>
    <emulator>/usr/bin/qemu-system-x86_64</emulator>
    <tpm model="tpm-crb">
      <backend type="emulator"/>
    </tpm>
  </devices>
</domain>

# virsh define minimal.xml
error: Failed to define domain from minimal.xml
error: unsupported configuration: TPM version '2.0' is not supported

So we know this is very early on (e.g. before actually spawning the guest).
Next: Need to look into the definition step in detail why it is failing.