Remapping Table for Message Signaled Interrupts
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Solution Overview
Problem
Existing peripheral interface technologies, such as PCIe, face challenges in securely managing message signaled interrupts (MSIs) without exposing the interrupt controller's address space to external devices, which can lead to security vulnerabilities and scalability issues due to the need for interrupt controllers to be aware of various encoding protocols.
Innovation Solution
Implementing a remapping table for each peripheral interface controller that translates virtual MSI addresses to the interrupt controller's address space, allowing the interrupt controller to remain agnostic to encoding schemes and preventing exposure of its address space, while also supporting non-contiguous interrupt mappings for improved security and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the interrupt controller's address space is exposed to external devices for MSI signaling, then MSI functionality is enabled, but security vulnerabilities arise from malicious access
Solution Approach 1:
The patent introduces a remapping table as an intermediary layer between the peripheral interface controller and the interrupt controller. This remapping table translates virtual MSI addresses to physical interrupt controller addresses, preventing direct exposure of the interrupt controller's address space while maintaining MSI functionality. The remapping table acts as a security barrier that mediates all address translations.
Solution Approach 2:
The patent segments the address space by creating a virtual address space for MSIs that is separate from the physical interrupt controller address space. The remapping table divides the translation process into discrete entries, where each entry maps a specific virtual address range to a physical address, enabling fine-grained control over which addresses are accessible and how they are translated.
2Adaptability or versatility
If the interrupt controller is designed to be aware of various encoding protocols, then multiple interrupt protocols can be supported, but device complexity increases
Solution Approach 1:
The patent extracts the protocol-specific encoding logic from the interrupt controller and places it in the remapping table within the peripheral interface controller. The interrupt controller is left with a simplified, protocol-agnostic interface that only needs to handle standardized address translations. The remapping table contains all the protocol-specific mapping information, effectively removing the burden of protocol awareness from the interrupt controller.
Solution Approach 2:
The remapping table serves as an intermediary that handles all protocol-specific translation logic. It converts various interrupt protocol encodings into a unified internal format that the interrupt controller can process without needing to understand the original encoding schemes. This mediator approach allows the system to support multiple protocols while keeping the interrupt controller simple.
Data Source
AI summary
Techniques are disclosed relating to address mapping for message signaled interrupts. In some embodiments, an apparatus includes interrupt control circuitry configured to process, from multiple client circuits, message signaled interrupts that include addresses in an interrupt controller address space. First and second interface controller circuitry may control respective peripheral interfaces for multiple devices. Remap control circuitry may be configured to access a first table based on at least a portion of virtual addresses of a first message signaled interrupt from the first interface controller circuit and generate a first address in the interrupt controller address space based on an accessed entry in the first table and access a second table based on at least a portion of virtual addresses of a second message signaled interrupt from the second interface controller circuit and generate a second address in the interrupt controller address space based on an accessed entry in the second table.