Extended MSI Message Data for Interrupt Source Identification
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Solution Overview
Problem
The existing PCI Express communication protocols rely on side channels to provide source identifiers and additional information, leading to increased power consumption and complex wiring, as they strip and reinsert headers, which is inefficient.
Innovation Solution
The implementation of extended Message Signaled Interrupts (MSI) message data that utilizes unused bits in the MSI message data to include system-level identifiers and other information, eliminating the need for side channels by embedding this data directly within the MSI message, thereby simplifying wiring and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If side channels are used to provide source identifiers and additional information, then the PCIe system can maintain backward compatibility and provide interrupt information, but power consumption increases and wiring complexity increases
Solution Approach 1:
The patent combines the source identifier and additional interrupt information directly into the MSI message data field, merging multiple functions (identification and information transfer) into a single communication channel, thereby eliminating the need for separate side channels and reducing power consumption
Solution Approach 2:
The MSI message data field is designed to serve multiple purposes: it carries the source identifier for interrupt verification and simultaneously transports additional information such as system level identifiers, making the field universal and eliminating the need for dedicated side channels
2Reliability
If side channels are used to provide source identifiers and additional information, then the PCIe system can maintain backward compatibility and provide interrupt information, but wiring complexity increases
Solution Approach 1:
The patent merges the source identifier and additional information into the existing MSI message data field, combining multiple communication functions into a single channel and thereby simplifying the wiring architecture by eliminating separate side channels
Solution Approach 2:
The patent extracts the source identifier and additional information from the header and places them directly into the message data field, removing the need for separate side channel wiring while maintaining all necessary communication functions
3Reliability
If headers are stripped and reinserted in the PCIe system, then source identifiers can be provided to memory management units, but processing efficiency decreases
Solution Approach 1:
The patent places the source identifier and additional information directly into the message data field in advance, so that the memory management unit and interrupt controller can access this information immediately without waiting for header stripping and reinsertion operations
Solution Approach 2:
The patent extracts the source identifier and additional information from the header structure and embeds them directly in the message data field, eliminating the need for header stripping and reinsertion operations and thereby improving processing efficiency
Data Source
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AI summary
Extended message signaled interrupts (MSI) data are disclosed. In one aspect, MSI bits are modified to include a system level identifier. In an exemplary aspect, an upper sixteen bits of the MSI message data are modified to be the system level identifier. By providing the system level identifier within the MSI message data, an interrupt controller can verify the interrupt source.