I/O Virtualization via Direct Guest Adapter Access

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Solution Overview

Problem

Conventional input/output virtualization methods require a privileged operating system to own and fully virtualize input/output resources, leading to single points of failure, degraded performance, and bottlenecks due to buffer remapping and copying, as well as increased latency and driver requirements.

Innovation Solution

A system and method that configure an input/output adapter using a back-end driver component in the privileged operating system address space, allowing registration for catastrophic event information and communication with active front-end driver components in guest operating systems, enabling isolated input/output operations without traversing the back-end driver for all communications, thus eliminating single points of failure and bottlenecks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a privileged operating system fully virtualizes input/output resources to all guest operating systems, then input/output virtualization is achieved, but single points of failure and performance degradation occur due to buffer remapping and copying

Engineering Contradiction:

Improveinput/output virtualization capabilityVSAvoidsingle point of failure

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The driver component is divided into multiple instances distributed across different guest operating systems. Each guest OS runs its own driver instance that communicates directly with the input/output adapter, eliminating the single point of failure in the privileged OS driver. This segmentation allows the system to maintain input/output virtualization while improving reliability through distribution.

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

If a privileged operating system fully virtualizes input/output resources, then input/output virtualization is achieved, but performance degradation occurs due to buffer remapping and copying

Engineering Contradiction:

Improveinput/output virtualization capabilityVSAvoidinput/output performance

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The buffer remapping and copying operations are extracted from the privileged operating system driver and performed directly by the driver instances running in guest operating systems. This eliminates the performance penalty of cross-OS buffer operations, as each driver instance operates within its own address space and can access buffers directly without remapping or copying through the privileged OS.

Inventive Principle:

Principle #2Taking out (Extraction)

3Ease of operation

If all communications traverse the back-end driver component in the privileged operating system, then centralized control is maintained, but bottlenecks and increased latency occur

Engineering Contradiction:

Improvecentralized controlVSAvoidcommunication latency

Core Design Contradiction:

Ease of operationVSLoss of time

Solution Approach 1:

Driver instances are pre-configured with the necessary permissions and communication channels to interact directly with the input/output adapter. This preliminary setup allows guest operating systems to bypass the privileged OS driver for time-critical input/output operations, reducing latency while maintaining centralized configuration control through the initial setup phase.

Inventive Principle:

Principle #10Preliminary action

4Device complexity

If a privileged operating system owns input/output resources, then resource management is simplified, but driver requirements and system complexity increase

Engineering Contradiction:

Improveresource management structureVSAvoiddriver requirements

Core Design Contradiction:

Device complexityVSEase of manufacture

Solution Approach 1:

The driver instances running in guest operating systems serve multiple functions: they manage input/output operations for their respective guest OS, communicate with the input/output adapter directly, and implement the virtualization logic locally. This multi-functionality eliminates the need for complex privileged OS driver code, as the driver functionality is universalized across multiple independent instances rather than centralized in a single complex driver.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS8176501B2Enabling efficient input/output (I/O) virtualization

Publication Date: 2012.05.08 DELL PROD LP

AI summary

A method for virtualizing input/output whereby a back-end driver component running back-end in a privileged operating system address space configures an input/output adapter through a setup/control path is disclosed. The back-end driver component is used to register with the input/output adapter to allow for the receipt of information concerning a catastrophic event. Catastrophic event data is transmitted to an active front-end driver component running in a guest operating system address space, where a communication path was established between the active front-end driver component and the back-end driver component. The back-end driver component listens for requests from the active front-end driver component. Upon receipt, an input/output context association is established between an input/output context in the input/output adapter and the active front-end driver component. The association enables the guest operating system to perform an isolated input/output operation directly with the input/output adapter through a respective data input/output path.