VMM Hot Migration via Page Table Mapping Instead of Memory Copy
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Solution Overview
Problem
Existing virtual machine migration methods require significant computing resources and time due to the need to copy and release memory contents, especially in scenarios with large memory spaces, making it difficult to upgrade virtual machine monitors (VMMs) without interrupting services.
Innovation Solution
A method that establishes a mapping between host virtual and physical address spaces by modifying page table entries, allowing virtual machines to be deployed and migrated without copying memory contents, thus reducing resource and time requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If whole memory space contents are copied for virtual machine migration, then migration can be performed, but computing resources equal to the memory space must be reserved and the process becomes complex and time-consuming
Solution Approach 1:
The patent extracts only the necessary mapping relationship information (page table entries) from the virtual machine's memory space, rather than copying the entire memory contents. This allows migration to proceed with minimal resource reservation while maintaining service continuity, directly resolving the contradiction between reliability and productivity.
Solution Approach 2:
The patent segments the memory migration process into two distinct phases: first copying only the page table entries (mapping relationships) to establish address space mappings, and then allowing the virtual machine to access physical memory directly through these mappings. This segmentation eliminates the need to copy entire memory contents, significantly improving migration efficiency while preserving service continuity.
2Reliability
If computing resources are reserved for memory copying during migration, then migration can be performed, but resource reservation becomes difficult when memory spaces are large (tens or hundreds of GB)
Solution Approach 1:
The patent extracts only the essential mapping relationship data (page table entries) rather than the entire memory contents, reducing the quantity of computing resources required from tens or hundreds of GB to a minimal amount of mapping data. This enables migration completion even when large memory spaces are involved, as the resource requirement is reduced to just the mapping information.
Solution Approach 2:
The patent performs preliminary action by pre-establishing the address space mappings through page table entry copying before the actual memory access occurs. This preliminary setup of mapping relationships allows the virtual machine to immediately access physical memory without requiring large buffer resources, enabling migration completion with minimal resource consumption.
3Reliability
If traditional migration methods are used, then virtual machines can be migrated, but the process becomes very complex and takes a great deal of time and labor when larger numbers of virtual machines need to be migrated
Solution Approach 1:
The patent segments the migration process into a simple two-step procedure: (1) copy page table entries to establish mapping relationships, and (2) activate the virtual machine on the target system. This segmentation eliminates the complex multi-phase processes of traditional migration, dramatically reducing migration time and labor while ensuring migration success through the established mapping relationships.
Solution Approach 2:
The patent performs preliminary action by pre-establishing the address space mappings through page table entry copying before virtual machine activation. This preliminary setup ensures that when the virtual machine starts, all memory mappings are already in place, eliminating the need for complex runtime memory management and significantly reducing migration time and labor requirements.
Data Source
AI summary
A virtual machine deployment method, a virtual machine live migration method, a VMM upgrading method, a server, and a computer-readable storage medium are disclosed. The virtual machine deployment method includes: establishing mapping between a host virtual address (HVA) space for a post-upgrading virtual machine and a host physical address (HPA) space for a pre-upgrading virtual machine according to a mapping relationship between a HVA space for the pre-upgrading virtual machine and the HPA space for the pre-upgrading virtual machine. The post-upgrading virtual machine is deployed on a post-upgrading virtual machine monitor (VMM), and the post-upgrading virtual machine is identical in memory configuration with the pre-upgrading virtual machine running on a pre-upgrading VMM (S110).