Hardware TPM Virtualization for Secure VM Key Isolation

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Solution Overview

Problem

Existing virtual machine (VM) security systems in cloud computing environments rely on hypervisor-stored trusted platform modules (TPMs) which are vulnerable to compromise, exposing security information if the hypervisor is compromised.

Innovation Solution

Implementing TPM functionality in a hardware security platform (HSP) that is communicatively coupled to the hypervisor, storing security information such as encryption keys and measurements in non-volatile memory of the HSP, ensuring hardware-backed protection and isolation of TPM data for each VM.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If TPM functionality is implemented in the hypervisor layer, then VM security management is simplified and centralized, but security is compromised if the hypervisor is compromised

Engineering Contradiction:
Improvecentralized TPM managementVSAvoidsecurity protection
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent extracts TPM functionality from the hypervisor layer and implements it in the hardware security platform. The HSP contains dedicated TPM logic and non-volatile memory for storing security information, separating the security-critical functions from the potentially vulnerable hypervisor environment. This allows centralized management while improving security isolation.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The hardware security platform acts as an intermediary between virtual machines and the hypervisor for TPM operations. The HSP receives TPM commands from the hypervisor, processes them in hardware-isolated TPM logic, and returns results, thereby protecting security information from direct hypervisor access while maintaining centralized control.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If security information is stored in hypervisor memory, then access and management is convenient, but confidentiality is compromised upon hypervisor compromise

Engineering Contradiction:
Improveaccess convenienceVSAvoidsecurity information exposure
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent extracts security information storage from hypervisor memory to the non-volatile memory of the hardware security platform. The HSP's NVM is dedicated to storing TPM security information such as encryption keys and measurements, physically isolating it from hypervisor memory and preventing exposure even if the hypervisor is compromised.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The hardware security platform provides localized, dedicated storage for each virtual machine's security information within its non-volatile memory. The TPM logic in the HSP can selectively access and manage security information for specific VMs, providing both convenience of access and protection through hardware-enforced isolation.

Inventive Principle:
Principle #3Local quality

3Productivity

If multiple VMs share a single hypervisor-based TPM, then resource utilization is improved, but security isolation between VMs is weakened

Engineering Contradiction:
Improveresource utilizationVSAvoidsecurity isolation
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The hardware security platform provides universal TPM functionality that can serve multiple virtual machines simultaneously. The HSP's TPM logic can process TPM commands for different VMs and manage their respective security information in its non-volatile memory, achieving high resource utilization while maintaining security isolation through hardware-enforced boundaries.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The hardware security platform segments security information storage and management for each virtual machine within its hardware boundaries. While the HSP serves multiple VMs, it maintains distinct security contexts and isolation barriers for each VM's TPM data, ensuring that compromise of one VM does not affect others while efficiently utilizing the shared HSP resources.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4384931B1Hardware virtualized TPM into virtual machines
Publication Date: 2026.02.18 MICROSOFT TECHNOLOGY LICENSING LLC
  • EP4384931B1 patent drawingFigure 1A
  • EP4384931B1 patent drawingFigure 1B
  • EP4384931B1 patent drawingFigure 2

AI summary

Methods, systems, apparatuses, and computer-readable storage mediums described herein enable executable code of a hardware security platform (HSP) circuit to communicate with a hypervisor in a separate processor. The hypervisor generates and manages virtual machines. The HSP code comprises trusted platform module (TPM) logic, that processes TPM commands received via the hypervisor, and in response to the processing, communicates security information (e.g., measurements, keys, authorization data) with the virtual machines via the hypervisor. The TPM logic receives security information related to a virtual machine from the hypervisor and stores the security information in non-volatile memory of the HSP circuit, where security information from a particular VM is distinguishable from security information from another VM in the HSP memory. The hypervisor (and VMs) communicate via a network fabric with the HSP circuit within an SOC, or the HSP may reside on a discrete chip and communicate via a secure encrypted channel.