VM Migration via Virtual CPU Descriptors

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The migration of virtual machines can result in unpredictable latencies and downtime, impacting the performance of applications running on the virtual machines.

Innovation Solution

A hypervisor that performs virtual machine migration using virtual CPU descriptors, where a file with vCPU data is transmitted from the original virtual machine to the new one, allowing for a transfer of control at the vCPU level without pausing the original virtual machine.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If virtual machine migration is performed using traditional methods, then the virtual machine can be transferred from one host to another, but unpredictable latencies and downtime occur impacting application performance

Engineering Contradiction:

Improveapplication performanceVSAvoidmigration downtime

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent segments the virtual machine state into individual vCPU descriptor files, where each vCPU's state is captured and migrated independently. This allows parallel migration of multiple vCPUs without requiring the entire VM to be paused, thereby reducing migration downtime while maintaining application performance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary actions by capturing vCPU state information into descriptor files before the actual migration occurs. These descriptors contain all necessary state information (registers, memory mappings, execution state) that can be quickly restored on the destination host, enabling fast migration with minimal downtime.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If virtual machine migration is performed with state restoration, then the virtual machine can resume execution on the new host, but migration latency increases

Engineering Contradiction:

Improvestate restoration accuracyVSAvoidmigration latency

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent creates lightweight copy descriptors that reference the original vCPU state information without requiring complete state duplication. These descriptors contain essential state information (program counter, registers, memory state) that can be quickly copied and restored, reducing migration latency while ensuring accurate state restoration.

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The patent changes the representation of vCPU state from complete binary state images to structured descriptor files with specific parameters (execution state, register values, memory mappings). This parameterized representation enables selective restoration of critical state elements, reducing restoration time while maintaining accuracy.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS20250199837A1Virtual machine migration with virtual CPU descriptors

Publication Date: 2025.06.19 RED HAT INC

AI summary

A computing device determines that a workload of a first virtual machine is to be transferred to a second virtual machine. The computing device generates a file comprising virtual CPU (vCPU) data that describes current conditions of the first virtual machine. The computing device transmits the file from the first virtual machine to the second virtual machine. The computing device restores the current conditions of the first virtual machine on the second virtual machine based on the file. The computing device sends a signal to the first virtual machine indicating that the current conditions of the first virtual machine are restored on the second virtual machine.