Enabling TPM emulation for Qemu Win10 guests

[Sam Varshavchik]

If you're running a qemu VM with a Windows 10 guest (in F34) and you  
successfully enabled TPM emulation, I'd like to compare notes with you.

I used virt-manager to enable TPM 2.0, both TIS and CRB types:

<tpm model="tpm-tis">
 <backend type="emulator" version="2.0"/>
 <alias name="tpm0"/>
</tpm>

and

<tpm model="tpm-crb">
 <backend type="emulator" version="2.0"/>
 <alias name="tpm0"/>
</tpm>

My fully activated/licensed Windows 10 VM (21H1) refuses to recognize TPM.  
"Security Processor Troubleshooting" reports:

"Your device does not support this feature."

I've read multiple reports that this should work, so I must be missing  
something. Looking at a working qemu configuration in /etc/libvirt/qemu is  
the only thing I can think of.