We have a physical Xeon host (bare metal - BM host) with a hardware TPM installed on it. The BM host's attestation status is established at through boot-time measurements captured and written to the PCRs on it's TPM.
An agent program on the BM host transmits a trust quote when an attestation challenge is received. Each BM host uses a unique Attestation Identity Keypair (AIK) the private key of which is bound to the TPM. The public AIK is shared with a KMIP key broker service (Key Management System - KMS) which verifies the attestation status of the host, wraps the key using the public AIK, and transfers the key to the BM host. The private AIK being sealed in the TPM, is unsealed and used to decrypt the KMS key.
The problem I am trying to solve is the secure retrieval of keys from the KMS I was wondering if this same process could be applied to a VM instance using a virtual TPM (vTPM) or emulated software TPM such as IBM's implementation.
What would be the challenges in this scenario, and are there are any alternative solutions I could try?