Memory Management Unit Hypervisor Supervisor Mode Address Translation
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Solution Overview
Problem
In multi-core microprocessor systems with hypervisors, there is a challenge in efficiently managing memory access and translation between different operating systems running in supervisor and hypervisor modes, particularly in ensuring secure and efficient allocation of physical addresses while allowing guest operating systems to access virtual memory without direct hardware access.
Innovation Solution
A memory management unit (MMU) with register tables for logical-to-real address translation (LRAT) and configuration memory management, allowing selective operation in hypervisor or supervisor modes, enabling secure write access and memory mapping based on privilege levels, and preventing unauthorized access to physical addresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hypervisor is introduced to manage multiple operating systems on physical hardware, then resource allocation and isolation between operating systems is improved, but system complexity and overhead increase
Solution Approach 1:
The patent introduces a memory management unit (MMU) as an intermediary component between the hypervisor and physical memory. The MMU includes register tables that store mapping relationships between logical addresses used by guest operating systems and physical addresses of actual hardware memory. This intermediary structure enables automatic address translation and memory access control, reducing the hypervisor's processing overhead while maintaining reliable resource isolation between operating systems.
2Speed
If guest operating systems are allowed to access virtual memory directly, then access speed is improved, but security and control are worsened
Solution Approach 1:
The patent implements a self-service mechanism where the memory management unit automatically performs address translation using pre-configured register tables. When a guest operating system accesses virtual memory, the MMU autonomously translates logical addresses to physical addresses without requiring hypervisor intervention for each access. This self-service approach maintains high access speed while ensuring security through hardware-enforced address validation and isolation boundaries.
3Productivity
If physical addresses are mapped directly to hardware, then address translation efficiency is improved, but flexibility and virtualization capability are worsened
Solution Approach 1:
The patent segments the address translation process into multiple hierarchical levels using register tables. The MMU divides physical address space into manageable segments and maintains separate mapping entries in register tables for different logical-to-physical address relationships. This segmentation enables efficient direct mapping for allocated memory while preserving the ability to create multiple virtual memory configurations, thus maintaining both translation efficiency and virtualization flexibility.
4Quantity of substance
If multiple operating systems share the same physical memory space, then memory utilization is improved, but access control and isolation are worsened
Solution Approach 1:
The patent implements a universal memory management architecture where the same memory management unit and register table mechanism serve multiple operating systems simultaneously. The MMU provides multi-functional address translation capabilities, handling logical-to-physical address mapping for different guest operating systems through a unified hardware structure. This universal approach enables efficient memory sharing and high utilization while maintaining strict access control and isolation through hardware-enforced translation boundaries.
Data Source
AI summary
The invention pertains to a memory management unit for a microprocessor system, the memory management unit being connected or connectable to at least one processor core of the microprocessor system and being connected or connectable to a physical memory of the microprocessor system. The memory management unit is adapted to selectively operate in a hypervisor mode or in a supervisor mode, the hypervisor mode and the supervisor mode having different privilege levels of access to hardware The memory management unit comprises a first register table indicating physical address information for mapping at least one logical physical address and at least one actual physical address onto each other; a second register table indicating an allowed address range of physical addresses accessible to a process running in or under supervisor mode; wherein the memory management unit is adapted to prevent write access to the second register table by a process not in hypervisor mode. The memory management unit is further adapted to allow write access to the first register table of a process running in or under supervisor mode to reconfigure the physical address information indicated in the first register table with memory mapping information relating to at least one physical address, if the at least one physical address is in the allowed address range, and to prevent write access to the first register table of the process running in or under supervisor mode if the at least one physical address is not in the allowed address range. The invention also pertains to a microprocessor system and a method for managing memory.