Hypervisor Policy Enforcement for Virtual Processor Hotplug

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Solution Overview

Problem

Existing virtualized computer systems lack an efficient method to manage processor hotplug requests from guest operating systems without violating resource utilization policies and without requiring shutdown and restart of virtual machines.

Innovation Solution

A hypervisor determines whether to grant processor hotplug requests based on a defined policy, selecting an appropriate physical proximity domain for the additional virtual processor, and notifies the guest operating system accordingly, allowing dynamic handling of requests without shutdown.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If processor hotplug requests are granted dynamically without shutdown, then system availability and flexibility are improved, but resource utilization policy compliance becomes difficult to ensure

Engineering Contradiction:

Improveprocessor hotplug capabilityVSAvoidresource utilization policy compliance

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The hypervisor continuously monitors physical processor utilization metrics and uses this feedback to dynamically evaluate hotplug requests against predefined policies. When a hotplug request arrives, the hypervisor checks current utilization levels and policy constraints, granting or denying the request based on real-time system state, thereby maintaining policy compliance while enabling dynamic processor management.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system transitions from static processor allocation to dynamic processor management where the hypervisor can evaluate and adjust hotplug requests in real-time based on current resource utilization. This dynamic approach allows the system to adapt processor allocation to changing workload conditions while enforcing policy constraints, resolving the contradiction between flexibility and compliance.

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If traditional processor hotplug methods are used, then system flexibility is improved, but virtual machine shutdown and restart is required which reduces productivity

Engineering Contradiction:

Improveprocessor configuration flexibilityVSAvoidvirtual machine availability

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The hypervisor performs preliminary evaluation of hotplug requests by checking policy compliance and resource utilization metrics before actually allocating the virtual processor. This preliminary action allows the system to prepare for processor hotplug operations without requiring VM shutdown, maintaining both flexibility and continuous availability by pre-validating requests against system state.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The hypervisor acts as an intermediary between the guest operating system and the physical processor resources. It receives hotplug requests from the guest OS, evaluates them against policies and current utilization, and mediates the actual processor allocation. This intermediary role enables flexible processor management while maintaining VM continuity without shutdown.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Adaptability or versatility

If processor hotplug requests are freely granted, then virtual machine flexibility is improved, but physical processor overutilization occurs violating resource policies

Engineering Contradiction:

Improvevirtual processor allocation flexibilityVSAvoidresource utilization policy violations

Core Design Contradiction:

Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The hypervisor implements a feedback mechanism that continuously monitors physical processor utilization metrics and compares them against policy thresholds. When evaluating hotplug requests, it uses this feedback to determine whether granting the request would violate resource policies, thereby preventing overutilization while still allowing flexible processor allocation within policy constraints.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system applies preliminary anti-action by preemptively evaluating hotplug requests against resource utilization policies before allocation occurs. The hypervisor checks whether the requested virtual processor would cause policy violations based on current physical processor utilization, and denies requests that would harm resource compliance, preventing harmful overutilization before it occurs.

Inventive Principle:

Principle #9Preliminary anti-action

Data Source

PatentUS9575788B2Hypervisor handling of processor hotplug requests

Publication Date: 2017.02.21 RED HAT ISRAEL

AI summary

A system and method are disclosed for determining whether to grant requests for additional virtual processors for a virtual machine (referred to as “processor hotplug requests”). In accordance with one embodiment, a hypervisor receives a request from a guest operating system of a virtual machine, where the request is for an additional virtual processor for the virtual machine. The hypervisor then determines whether or not to grant the request based on a policy.