Virtual machine system and operating method thereof

• US 20080028124A1
• Filed: 07/25/2007
• Published: 01/31/2008
• Est. Priority Date: 07/26/2006
• Status: Active Grant

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Tago, Akira
• Granted Patent: US 7,797,507 B2
• Time in Patent Office: Days
• US Class Current: 711/6
• CPC Class Codes: G06F 12/0284 Multiple user address space allocation, e.g. using different base addresses interprocessor communication G06F15/163
• CPC Class Codes: G06F 12/1009 using page tables, e.g. page table structures
• CPC Class Codes: G06F 12/109 for multiple virtual address spaces, e.g. segmentation G06F12/1036 takes precedence
• CPC Class Codes: G06F 2009/45583 Memory management, e.g. access or allocation
• CPC Class Codes: G06F 2212/656 Address space sharing
• CPC Class Codes: G06F 9/45558 Hypervisor-specific management and integration aspects
• CPC Class Codes: G06F 9/5016 the resource being the memory
• CPC Class Codes: G06F 9/544 Buffers; Shared memory; Pipes

Abstract

A virtual machine system includes a physical memory and a virtual machine monitor (VMM) When a kernel image of one guest OS, in startup of the one guest OS, has already been loaded on the physical memory, the VMM starts up one guest OS with the kernel image.

Claims

1. A virtual machine system, comprising:

a physical memory; and

a virtual machine monitor (VMM), when a kernel image of one guest OS, in startup of said one guest OS, has already been loaded on said physical memory, said VMM starts up one guest OS with said kernel image.

2. The virtual machine system according to claim 1,

said VMM has a management table representing a state of a kernel image loaded into said physical memory, and said VMM checks whether or not said kernel image of said one guest OS has been loaded on said physical memory based on said management table.

3. The virtual machine system according to claim 2,

when said kernel image of said one guest OS, in startup of said one guest OS, is not loaded on said physical memory, said VMM loads said kernel image of said one guest OS on said physical memory.

4. The virtual machine system according to claim 3,

wherein said VMM adds a new entry of said kernel image of said one guest OS on said management table, when said kernel image of said one guest OS is loaded on said physical memory.

5. The virtual machine system according to claim 4,

wherein said VMM checks whether or not said kernel image of said new entry is the same as said kernel image of other entry based said management table, when there is said other entry except for said new entry.

6. The virtual machine system according to claim 5,

when said other entry whose kernel image is the same as said kernel image of said new entry exists, said VMM changes mapping of the address regarding said kernel image of said one entry into mapping of the address regarding said kernel image of said other entry.

7. The virtual machine system according to claim 5,

said management table has an entry representing a size of said kernel image loaded, said VMM checks by comparing the size of the kernel image of each entry.

8. The virtual machine system according to claim 7,

wherein said management table has an entry representing an address of said kernel image loaded, said VMM checks by reading out said kernel image of each entry based on said management table and comparing said kernel image read out.

9. The virtual machine system according to claim 6,

wherein said VMM further deletes said new entry from said management table and frees up an area where said kernel image of said one guest OS is loaded when said VMM changes mapping of the address regarding said kernel image of said one entry into mapping of the address regarding said kernel image of said other entry.

10. The virtual machine system according to claim 9,

wherein said VMM deletes said other entry from said management table and frees up said area where said kernel image of said other guest OS is loaded, when there is no other than guest OS using said kernel image of said other guest OS in shut-down of said other guest OS.

11. The virtual machine system according to claim 10,

wherein said entry of said management table includes the number of a guest OS using a kernel image loaded on said physical memory, said VMM changes the number of said new entry and said other entry when said VMM changes mapping of the address regarding said kernel image of said one entry into mapping of the address regarding said kernel image of said other entry.

12. An operating method of a virtual machine system, wherein said virtual machine system includes a virtual machine monitor (VMM), said method comprising the step of:

when a kernel image of one guest OS, in startup of said one guest OS, has already been loaded on a physical memory, starting up one guest OS with said kernel image.

13. The operating method of the virtual machine system according to claim 12, said method comprising:

checking whether or not said kernel image of said one guest OS has been loaded on said physical memory based on a management table in VMM representing a state of said kernel image loaded on said physical memory.

14. The operating method of the virtual machine system according to claim 13, said method comprising:

loading said kernel image of said one guest OS on said physical memory when said kernel image of said one guest OS is not loaded on said physical memory in startup of said one guest OS.

15. The operating method of the virtual machine system according to claim 14,

adding an new entry of said kernel image of said one guest OS on said management table when said kernel image of said new guest OS is loaded on said physical memory.

16. The operating method of the virtual machine system according to claim 15, said method comprising:

checking, when there is other entry except for said new entry,

whether or not said kernel image of said new entry is the same as said kernel image of said other entry based said management table.

17. The operating method of the virtual machine system according to claim 16, said method comprising:

changing mapping of the address regarding said kernel image of said one entry into mapping of the address regarding said kernel image of said other entry when said other entry whose kernel image is the same as said kernel image of said new entry exists.

18. The operating method of the virtual machine system according to claim 16, said method comprising:

checking whether or not said kernel image of said new entry is the same as said kernel image of said other entry by comparing the size of the kernel image of each entry in said management table representing the size of said kernel image loaded.

19. The operating method of the virtual machine system according to claim 18,

wherein said management table has an entry representing an address of said kernel image loaded, and said checking is done by comparing said kernel image of said one guest OS with said kernel images read out based on said entry of said management table.

20. The operating method of the virtual machine system according to claim 19, said method comprising:

deleting said new entry from said management table and freeing up said area where said kernel image of said new guest OS is loaded.

21. The operating method of the virtual machine system according to claim 20, said method comprising:

deleting said other entry from said management table and freeing up said area where said kernel image of said other guest OS is loaded when there is no other than guest OS using said kernel image of said other guest OS in shut-down of said other guest OS.

22. The operating method of the virtual machine system according to claim 21,

wherein said entry of said management table includes the number of a guest OS using a kernel image loaded, and further comprising:

changing the number of said other entry and said new entry when changing mapping of the address regarding said kernel image of said one entry into mapping of the address regarding said kernel image of said other entry.

23. A computer readable medium recording thereon a program for enabling a computer providing a virtual machine environment to execute the step of:

when a kernel image of one guest OS, in startup of said one guest OS, has already been loaded on a physical memory, starting up one guest OS with said kernel image.