Open /dev/tpm0: device or resource busy

Hello guys

When trying to OpenTPM() to perform attestation, I always get the following error: "Open /dev/tpm0: device or resource busy".
When I run the same piece of code in a real HW TPM, everything works fine, but when running in a virtualized environment (VMs instantiated through qemu and vTPM by means of SWTPM, TSS, ABRMD) I get this error.

Has anyone been through this before?

Any help is appreciated.

Start with the OpenTPM() call and the /dev/tpm0 error, then reproduce the attestation attempt in the reported real-TPM and QEMU/SWTPM/TSS/ABRMD environments. Compare device access and determine why the virtualized setup returns "device or resource busy"; done means identifying a reproducible cause and documenting or correcting the behavior.

Written by the indexing model from the issue text.