VIRTIOFS Offloading via DMA for Host-VM Shared Directory Access

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Solution Overview

Problem

Existing virtual machine technologies face performance issues due to software running on the host, which affects communication and directory sharing between the host and virtual machine, especially after implementing a data processing unit (DPU), leading to failures in shared directory implementation.

Innovation Solution

Offload the VIRTIOFS process to a data processing unit (DPU) and establish a DMA communication channel using DMA driver controllers in different operating systems to enable direct memory access, ensuring communication and directory sharing functionality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the VIRTIOFS process is offloaded to a DPU to improve host performance, then host performance is improved, but communication between the host and virtual machine becomes more complex

Engineering Contradiction:
Improvehost performanceVSAvoidcommunication complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent introduces a DMA driver front-end controller in the host operating system and a DMA driver back-end controller in the DPU's operating system as intermediary components. These controllers establish a DMA communication channel that bridges the host and DPU, enabling direct memory access and simplifying the communication protocol despite the architectural complexity of offloading

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The communication system is segmented into distinct components: the VIRTIOFS process on the DPU, the DMA driver front-end controller in the host OS, the DMA driver back-end controller in the DPU's OS, and the DMA communication channel. This segmentation allows each component to operate independently with well-defined interfaces, managing complexity through modular design

Inventive Principle:
Principle #1Segmentation

2Productivity

If the VIRTIOFS process is offloaded to a DPU to improve host performance, then host performance is improved, but the shared directory function may fail

Engineering Contradiction:
Improvehost performanceVSAvoidshared directory function
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The DMA communication channel acts as a reliable intermediary that ensures proper data transmission between the host and the DPU's VIRTIOFS process. The channel establishes guaranteed communication paths for file system operations, maintaining the reliability of shared directory access despite the process being offloaded to a separate processing unit

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The DMA driver controllers implement feedback mechanisms to monitor and manage the communication channel between the host and DPU. This feedback ensures that file system operations are properly acknowledged and executed, maintaining the reliability of the shared directory function even when the VIRTIOFS process runs on the DPU rather than the host

Inventive Principle:
Principle #23Feedback

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Improves performance of the host and virtual machine by maintaining directory sharing functions through direct memory access, allowing efficient communication and data processing between the host and virtual machine.

Implementation Method 1

establishing, through a DMA driver front-end controller configured in a first operating system in the host and a DMA driver back-end controller configured in a second operating system in the DPU, a DMA communication channel for the VIRTIOFS process to communicate with the virtual machine on the host

Methodology Applied
Scientific EffectDirect Memory Access (DMA):

Data Source

PatentEP4582944B1Offloading method and device for shared directory file system between host and virtual machine
Publication Date: 2026.02.18 BEIJING VOLCANO ENGINE TECH CO LTD
  • EP4582944B1 patent drawingFigure 1~2
  • EP4582944B1 patent drawingFigure 3~4
  • EP4582944B1 patent drawingFigure 5

AI summary

The present disclosure provides an offloading method and device for a shared directory file system between a host and a virtual machine, and relates to the field of virtual machine technologies. The method includes: offloading a VIRTIOFS process on a host to a DPU; establishing a DMA communication channel through a DMA driver front-end controller configured in a first operating system in the host and a DMA driver back-end controller configured in a second operating system in the DPU; and controlling, through the data processing unit DPU, the VIRTIOFS process to communicate with a virtual machine deployed on the host based on the DMA communication channel, to implement access to and data processing of the shared directory file system. According to the present disclosure, the VIRTIOFS process and the shared directory file system can be migrated from the host to the DPU, and the shared directory can be implemented through a direct memory access technology, so that performance of the host and/or the virtual machine can be improved.