JPH0740249B2 - Virtual memory control method in virtual computer system - Google Patents

Description

The present invention relates to a virtual storage control method in a virtual computer system.

[Conventional technology]

A virtual storage control method in a conventional virtual computer system will be described with reference to FIG. A virtual address (301) of a virtual computer (hereinafter referred to as a guest) undergoes conversion using a guest conversion table stored in the main memory of the guest (I). After applying the guest's prefix translation, get the guest's absolute main storage address (302). It is verified that this address is within the allowable range indicated by "L", then the offset indicated by "N" is added, and the address is converted into the virtual address (303) of the real computer (hereinafter referred to as the host). The virtual address of the host, as shown in II, is calculated using the host's translation table (30
4) receive conversion. In this specification, the absolute address (304) of the host will be simply referred to as “real address”. The above is “Nikkei Electronics 198
4.4.23 (No.341), pages 207 to 233, "Virtual Machine of System / 370 Extended Architecture".

[Problems to be solved by the invention]

As is well known, there are two types of virtual memory management functions (virtual memory management units). One is a virtual memory management function of an operating system of a virtual computer (hereinafter referred to as a guest OS), and the other is an operating system for a virtual computer system (this is referred to as a virtual computer monitor. (Abbreviated as VMM) virtual memory management function.

The above-mentioned virtual memory management control method in the conventional virtual computer system requires that the virtual memory management function of the guest OS perform virtual address conversion, and then the VMM virtual memory management function again performs address conversion. However, there is a drawback that the execution performance is lowered because the address translation must be performed in two steps.

Therefore, an object of the present invention is to share the virtual memory management function (virtual memory management unit) of the guest OS,
It is an object of the present invention to provide a virtual memory management system in a virtual computer system that can obtain a real address of a real memory only by one-step dynamic address translation of the virtual address.

[Means for solving problems]

A virtual memory management system in a virtual computer system according to the present invention is a computer system having a virtual memory management unit composed of a dynamic address conversion unit, a real memory management unit and a real memory management table, and an operating system of the same type operates. In a virtual memory control method of a virtual computer system for operating a plurality of computer systems in one real computer system, the virtual memory management units of the operating systems of the plurality of computer systems are placed in a system shared address space of a segmentation method and shared. The shared virtual memory management unit includes a sharing unit,
The dynamic address translation means for translating the virtual address of each operating system into a real address, and the real address of the real storage obtained by the dynamic address translation means are centrally managed based on the real storage management table. And a real memory management means, and the real address of the real memory can be obtained by only one-step dynamic address conversion of the virtual address.

〔Example〕

 Next, an embodiment of the present invention will be described with reference to the drawings.

Referring to FIG. 1 showing an embodiment of the present invention, a virtual computer system 1 of the present embodiment includes a real storage 6 and virtual computers A and B. Virtual machines A and B include operating systems 2 and 3, respectively. The virtual memory management function sharing means 4 and the virtual memory management unit 5 are shared by the virtual computers A and B. The virtual memory management unit 5 comprises a dynamic address translation means 50, a real memory management means 51 and a real memory management table 52.

Although only two virtual machines, that is, operating systems, which operate on the virtual machine system are provided in this embodiment, there may be two or more virtual machines.

In this embodiment, the virtual memory management function sharing means 4 sets the virtual memory management unit 5 to the operating systems 2 and 3.
Are to be shared on the virtual computer system 1 by using a segmentation method to locate them on the system shared address space of the operating systems 2 and 3. That is, the virtual address space in which the dynamic address translation unit 50, the real storage management unit 51, and the real storage management table 52 created by the operating system 2 are stored, the virtual / real address space to be managed, and the operating system 3 By setting the virtual address space in which the created dynamic address conversion means 50, the real memory management means 51 and the real memory management table 52 are stored and the virtual / real address space to be managed to be the same, the operating system 2 In and 3, the virtual memory management unit 5 can be shared.

Here, in the present invention, a segmentation method is adopted,
The reason why the paging method is not adopted will be described. As is well known, the paging method is a method in which a program is divided into pages of a certain size and allocation to the main memory is performed in page units. Therefore, the virtual address space of each guest OS becomes the same. With the paging method, it is necessary to perform address translation while determining which guest OS DAT table is used when performing address translation, which increases overhead. On the other hand, the segmentation method is
In this method, the virtual address space is divided into variable segments that have a logical meaning defined by the programmer, and main memory is allocated in units of this segment. The virtual address is represented by a two-dimensional address composed of a segment number and a relative number within the segment. Therefore, "guest OS shared address space" and "guest application dedicated address space under the guest OS" are added to the two-dimensional address space.
Can be set. As a result, when the segmentation method is adopted, the same address conversion (one-step conversion) as that of the real computer is performed and there is no performance degradation.

The virtual memory management unit 5 inputs the virtual address 20 of the operating system 2 or the virtual address 30 of the operating system 3 and performs address conversion. Please note that the virtual memory management unit 5 is different from VMM. The reason is clear because VMM cannot directly enter the virtual address of the guest operating system.

The dynamic address translation means 50 inputs the virtual address 20 of the operating system 2 and performs address translation by the segmentation / paging method. Similarly, the dynamic address translation means 50 inputs the virtual address 30 of the operating system 3 and performs address translation by the segmentation / paging method. As a result of the address conversion, if it exists in the real memory 6, the real address 60 is directly accessed with the real address 60. If it does not exist in the real memory 6, the real memory managing means 51 is notified of that fact.

The real memory management means 51 manages the use / unuse of the real address of the real memory 6 for each 4 Kbyte page.
An unused real page is allocated based on the above, and data or the like specified by the virtual address is loaded from the secondary storage device. The real page of the allocated real storage management table 52 is in the “used” state. If there is no unused real page, the most recently used real page among the real pages in the “used” state is searched for, the real page is pushed out from the real storage 6 to the secondary storage device, and then the real page is left unused. As a used page, perform the operation for the above unused page, then
The dynamic address translation means 50 is started again.

Next, with reference to FIG. 2, detailed operation of the virtual memory management function sharing means 4, which is the sharing means of the virtual memory management unit 5 placed in the system shared address space, will be described.

The processes A and B of the virtual computer A operate using the virtual storage management unit 5 of the segment S-1 which is a system shared segment. For this reason, the segment S-1 is the segment table display word string STWA linked by the process A.
-The kth entry of _A is linked to the segment table ST- _S , and the nth entry of the segment table ST- _S is linked. The nth entry of the segment table ST- _S defines that it is a system shared segment as an attribute of the segment. Similarly, for the process B, the segment table ST- _S starts from the kth entry of the segment table display word string STWA- _B (same value as k of the segment table display word string STWA- _A ) linked by the process B. It is linked.

The processes X and Y of the virtual machine B are also linked by the process X in order to use the same virtual memory management unit 5 as the processes A and B of the virtual machine A, that is, the segment S-1 can be accessed. The segment table ST- _S is linked from the k-th entry of the table display word string STWA- _X (the same value as the k of the segment table display word string STWA- _A ). Similarly, for the process Y, the segment table display word string STWA- _Y linked by the process _Y
The segment table ST- _S is linked from the k-th entry (the same value as k in the segment table display word string STWA- _A ).

This allows you to create a segment that is a system shared segment.
The virtual memory management unit 5 of S-1 is connected to the process A of the virtual computer A.
And B and the processes X and Y of the virtual machine B can be shared.

In addition, segment A-1, segment B-1, segment X-
1, segment Y-1 is a unique segment of processes A, B, X, and Y, segment AB-1 is a shared segment of processes A and B, and segment XY-1 is a shared segment of processes X and Y. is there.

〔The invention's effect〕

As described above, according to the present invention, the virtual address space in which the virtual memory management unit including the dynamic address translation unit, the real memory management unit, and the real memory management table is stored, and the virtual / real address space to be managed Is shared by multiple operating systems (guest OS), virtual addresses from each operating system (guest OS) can be stored in real memory using dynamic address translation means, real memory management means, and real memory management tables. It becomes possible to convert to a real address, and the real address of real memory can be obtained by one-step dynamic address conversion. Therefore, there is an effect that the execution performance becomes the same as when it operates on the virtual computer system as when it operates on the real computer system.

[Brief description of drawings]

1 is a block diagram showing a virtual computer system to which a virtual storage control system according to an embodiment of the present invention is applied, FIG. 2 is a system shared address space diagram of a virtual storage management function sharing means in FIG. 1, and FIG. FIG. 1 is a block diagram showing a conventional virtual memory control method. 1 ... Virtual computer system, 2, 3 ... Operating system (guest OS), 4 ... Virtual memory management function sharing means, 5 ... Virtual memory management unit, 6 ... Real memory, 20, 30 ...
Virtual address, 50 ... dynamic address conversion means, 51 ... real memory management means, 52 ... real memory management table, 60 ... real address.

Claims (1)

[Claims] 1. A computer system having a virtual memory management unit composed of a dynamic address conversion unit, a real memory management unit and a real memory management table, wherein one computer system in which operating systems of the same type operate is one real computer system. In a virtual storage control method for a virtual computer system that operates a plurality of computer systems, a sharing unit is provided that shares the virtual storage management unit of the operating system of the plurality of computer systems in a system shared address space of the segmentation method. The virtual storage management unit converts the virtual address of each operating system into a real address, and the real address of the real storage obtained by the dynamic address conversion unit is the real storage management unit. Based on the table, the above-mentioned notes that are centrally managed And a management unit, the virtual memory control system in the virtual computer system, wherein a real address of the real storage only dynamic address translation of the virtual address of one step is obtained.