TPM Access Locking for Secure Virtual Machine Control
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Solution Overview
Problem
Existing virtual machine monitors and virtual machines face inefficiencies and security risks when accessing a Trusted Platform Module (TPM) due to the need for complex emulation, which increases implementation complexity and reduces security.
Innovation Solution
A method and computing device design that allows virtual machine monitors and virtual machines to access a TPM serially by locking and unlocking the TPM based on demand, using a state machine to manage access requests, thereby enabling direct access without emulation, ensuring efficient and secure access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If full emulation of TPM is implemented, then virtual machines can access TPM functions, but implementation complexity increases and security is reduced
Solution Approach 1:
The patent extracts the TPM access control function from the virtual machine monitor and places it in a dedicated driver module. This separates the emulation complexity from the access control mechanism, allowing the VM monitor to remain simple while still providing secure TPM access to virtual machines through the driver's mediation layer.
Solution Approach 2:
The patent introduces a driver as an intermediary between the virtual machine and the TPM hardware. This driver handles the complex emulation and communication details, while the virtual machine simply needs to access the driver's interface. The intermediary absorbs the complexity and provides a simplified, secure access path.
2Reliability
If serial access control is implemented, then security is improved, but access efficiency is reduced
Solution Approach 1:
The patent implements preliminary action by having the driver pre-establish secure communication channels and pre-configure access control states before actual TPM access is needed. The serial access control is prepared in advance through driver initialization, allowing rapid sequential access without repeated security verification overhead.
Solution Approach 2:
The patent uses feedback mechanisms where the driver continuously monitors the access state and provides feedback to both the virtual machine and the TPM hardware. This enables efficient serial access by quickly determining when a virtual machine can safely access the TPM without requiring continuous complex verification, thus maintaining both security and efficiency.
Data Source
AI summary
Methods and apparatuses for accessing a trusted platform module (TPM) are disclosed. In an implementation, a method comprises receiving, by a virtual machine monitor from a first virtual machine in at least one virtual machine, a first notification message for requesting to access the TPM. In response to determining that the TPM is unlocked, locking, by the virtual machine monitor, the TPM to allow the TPM to be accessed only by the first virtual machine, and sending a first decision message to the first virtual machine indicating the first virtual machine to start performing a first access operation on the TPM. Receiving, by the virtual machine monitor, a second notification message from the first virtual machine, and unlocking, by the virtual machine monitor, the TPM in response to the second notification message.