Direct Interrupt Delivery to Virtual Processors
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Solution Overview
Problem
In virtualization environments, the frequent interception of interrupt requests by a Virtual Machine Monitor (VMM) can hinder performance by disrupting the execution of guest operating systems, as all interrupt requests typically need to be handled by the VMM, leading to potential bottlenecks and reduced efficiency.
Innovation Solution
The method involves enabling direct delivery of interrupt requests to virtual processors without requiring interception by the VMM, utilizing control logic within the processor to manage interrupt delivery and redirection, and configuring the Virtual Machine Control Structure (VMCS) to support this direct delivery, allowing certain interrupts to be handled by the virtual processor directly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all interrupt requests are intercepted and handled by the VMM, then the virtualization environment maintains complete control over resource allocation, but the system performance deteriorates due to frequent context switches and increased processing overhead
Solution Approach 1:
The patent segments interrupt handling into two paths: critical interrupts are intercepted by the VMM for centralized management, while non-critical interrupts are delivered directly to the virtual processor. This segmentation allows the system to maintain virtualization control for essential resources while improving performance by reducing unnecessary context switches for less critical interrupts.
Solution Approach 2:
The patent introduces an intermediary mechanism (the virtual processor's interrupt delivery mechanism) that sits between the interrupt source and the VMM. This intermediary can directly deliver interrupts to the virtual processor without requiring VMM intervention, thereby reducing the overhead of complete interception while maintaining VMM authority over critical resource allocation.
2Reliability
If the VMM intercepts every interrupt request to ensure proper resource allocation, then virtualization policies are enforced, but the execution time of guest operating systems increases due to frequent VM exits
Solution Approach 1:
The patent applies partial action by intercepting only the necessary interrupts for policy enforcement rather than all interrupts. The VMM maintains control over critical resource allocation by intercepting only those interrupts that require policy intervention, while allowing other interrupts to pass through directly to the virtual processor, thereby reducing the time lost to frequent VM exits.
3Stability of the object's composition
If the VMM handles all interrupts centrally, then resource allocation consistency is maintained, but the processing load on the VMM increases creating a bottleneck
Solution Approach 1:
The patent segments the interrupt handling workload between the VMM and the virtual processor. The VMM continues to manage critical resource allocation centrally to maintain consistency, while the virtual processor independently handles non-critical interrupts. This segmentation distributes the processing load and prevents the VMM from becoming a bottleneck.
Solution Approach 2:
The patent enables the virtual processor to serve itself by directly handling non-critical interrupts without requiring VMM intervention. This self-service capability allows the virtual processor to manage its own interrupt needs for resources it controls, reducing the processing load on the VMM while maintaining allocation consistency for critical resources.
Data Source
AI summary
Embodiments of apparatuses, methods, and systems for delivering an interrupt to a virtual processor are disclosed. In one embodiment, an apparatus includes an interface to receive an interrupt request, delivery logic, and exit logic. The delivery logic is to determine, based on an attribute of the interrupt request, whether the interrupt request is to be delivered to the virtual processor. The exit logic is to transfer control to a host if the delivery logic determines that the interrupt request is not to be delivered to the virtual processor.