Translation Load Instruction with Access Protection for TLB Management

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Solution Overview

Problem

Conventional multiprocessor systems face inefficiencies in loading translation entries into address translation structures, such as page frame tables and translation lookaside buffers, which can lead to increased latency and errors during memory-mapped I/O operations due to the need for frequent updates and invalidations of cache entries.

Innovation Solution

A processor core processes a translation load instruction that includes a protection field to specify desired access protections for a memory page, calculating an effective address and ensuring that a translation entry with the specified protections is stored in the translation structures, thereby optimizing the loading process and reducing latency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If translation entries are frequently updated and invalidated in translation structures, then the accuracy of address translation is improved, but the latency and processing time increase

Engineering Contradiction:

Improveaccuracy of address translationVSAvoidlatency during memory-mapped I/O operations

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The translation load instruction allows translation entries to be pre-loaded into the translation lookaside buffer (TLB) before they are actually needed for address translation. By anticipating future translation needs and loading entries in advance, the system reduces latency during actual memory-mapped I/O operations while maintaining translation accuracy through controlled loading based on protection fields and effective addresses

Inventive Principle:

Principle #10Preliminary action

2Speed

If translation entries are loaded into translation structures, then the speed of address translation is improved, but cache pollution and incorrect entries increase

Engineering Contradiction:

Improvespeed of address translationVSAvoidcorrectness of translation entries

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The translation load instruction incorporates protection fields that provide feedback mechanisms to ensure only appropriate translation entries are loaded into the TLB. The protection field specifies desired access protections that are verified during the loading process, preventing incorrect or unauthorized translation entries from polluting the cache while maintaining high translation speed through selective pre-loading

Inventive Principle:

Principle #23Feedback

3Adaptability or versatility

If manual management of translation entries is performed, then control over translation structures is improved, but the complexity of the system increases

Engineering Contradiction:

Improvecontrol over translation structuresVSAvoidcomplexity of translation management

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The translation load instruction enables a self-service mechanism where the processor can autonomously load translation entries into the TLB without requiring complex external management routines. The instruction includes fields for effective address and protection specifications, allowing the processor to self-manage translation cache contents while maintaining adaptability and control, thereby reducing overall system complexity

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS11226902B2Translation load instruction with access protection

Publication Date: 2022.01.18 INTERNATIONAL BUSINESS MACHINE CORPORATION

AI summary

A processor core processes a translation load instruction including a protection field specifying a desired access protection to be specified in a translation entry for a memory page. Processing the translation load instruction includes calculating an effective address within the memory page and ensuring that a translation entry containing the desired access protection is stored within at least one translation structure of the data processing system.