CPUID Spoofing for Legacy Application Compatibility

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Solution Overview

Problem

New devices often fail to achieve backwards compatibility with legacy applications due to differences in CPU performance, leading to synchronization errors and potential misuse of unsupported features.

Innovation Solution

A computing device mimics the capabilities of a legacy CPU by returning a spoofed processor ID in response to legacy applications, using modified CPUID instructions or hardware logic to ensure compatibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the CPU on the new device is faster than the CPU on the legacy device, then processing speed is improved, but synchronization errors occur and backwards compatibility is lost

Engineering Contradiction:

ImproveCPU processing speedVSAvoidsynchronization accuracy

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The patent changes the parameter reported by the CPUID instruction from the actual modern CPU capabilities to the legacy CPU capabilities. This parameter change allows legacy applications to operate with expected performance characteristics while running on faster hardware, preventing synchronization errors caused by premature data overwriting.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If the new device reports accurate CPU capabilities, then application optimization is improved, but legacy applications cannot run correctly

Engineering Contradiction:

Improveapplication execution efficiencyVSAvoidbackwards compatibility

Core Design Contradiction:

ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent creates a virtual copy of the legacy CPUID response and returns it to legacy applications. This copying approach allows the system to maintain accurate knowledge of modern CPU capabilities while presenting a faithful replica of legacy CPU characteristics to applications designed for older systems.

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The patent introduces an intermediary layer (the modified CPUID instruction handler) that sits between the legacy application and the actual CPU. This intermediary translates and adapts the capability information, allowing seamless communication between applications written for legacy systems and modern hardware without requiring application modification.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If the CPUID instruction returns accurate processor information, then system security is improved, but spoofing attacks become more difficult to detect

Engineering Contradiction:

Improvesystem securityVSAvoidspoofing detection difficulty

Core Design Contradiction:

ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent segments the CPUID instruction handling into different paths based on application type. Legacy applications receive spoofed capability information while modern applications receive accurate information. This segmentation allows the system to maintain security for modern applications while enabling legacy application compatibility without raising security alarms.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentEP3405864B1Spoofing cpuid for backwards compatibility

Publication Date: 2025.12.17 SONY INTERACTIVE ENTERTAINMENT LLC

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AI summary

To facilitate backwards compatibility, a computing device may respond to a call from an application for information regarding a processor on the computing device by returning information regarding a different processor than the processor on the computing device.