Comment 2 for bug 1913552

The following is mostly a note to myself, I'm still first of all waiting for the logs I asked above.

The config used in the example you linked is:

    <tpm model='tpm-crb'>
      <backend type='passthrough'>
        <device path='/dev/tpm0'/>
      </backend>
    </tpm>

Per https://libvirt.org/formatdomain.html#tpm-device about tpm-crb
"another available choice is the tpm-crb, which should only be used when the backend device is a TPM 2.0"

tpm-tis could be an alternative, but that also might be odd.
So far I mostly heard people use emulators [1][2]

in libvirt that is something like:
<tpm model="tpm-crb">
  <backend type="emulator" version="2.0"/>
</tpm>

Unfortunately my TPM is unhappy with me, also I have none of the further steps in place. So no testing from me atm (IIRC xnox had a setup like this once):
$ sudo /usr/sbin/tcsd -f
TCSD TDDL ioctl: (25) Inappropriate ioctl for device
TCSD TDDL Falling back to Read/Write device support.
TCSD TCS ERROR: TCS GetCapability failed with result = 0x1e

[1]: https://github.com/stefanberger/swtpm
[2]: https://launchpad.net/~stefanberger/+archive/ubuntu/swtpm-focal