JPH0319977B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a virtual storage control method in a virtual storage system, and more particularly to a virtual storage method in which real storage and virtual storage are primarily managed by hardware.

[Background of the invention]

In virtual storage systems, real storage (RS), usually called page tables or segment tables,
It has a table that manages the correspondence between virtual memory (VS) and virtual memory (VS), and uses them to convert addresses from virtual memory (virtual addresses) to addresses on real storage (real addresses). There is. Conventionally, the operating system (OS) managed this table by being aware of both RS and VS, but by converting this to firmware and limiting the software's awareness to VS, for example, 1 This is a virtual memory control method called a level addressing method. In this method, the address space that software is aware of is a single virtual address space, so as long as it maintains compatibility with existing programs that are assumed to operate under a 24-bit address space, for example, 24-bit addresses can be used. It is difficult to expand the capacity of VS beyond space.

[Purpose of the invention]

The purpose of the present invention is to eliminate the above-mentioned conventional problems, and to guarantee the operation of existing programs that have a limit on the size of the operating address space, while minimizing the amount of changes in hardware and software. An object of the present invention is to provide a virtual storage control method that has the effect of expanding virtual storage capacity and real storage capacity while minimizing the amount of storage.

[Summary of the invention]

The features of this invention include a directory that manages the correspondence between RS and VS, a mechanism for dividing VS into arbitrary sizes, and a mechanism for dividing VS into arbitrary sizes.
When each VS and each divided directory are called logical virtual spaces (LVS) and LVS directories, there is a mechanism for recognizing them.
A mechanism for converting an address on LVS (logical virtual address) to an address on RS (real address) using an LVS directory, and
By providing a mechanism to copy the contents of an LVS directory to another LVS directory, and creating multiple logical virtual spaces on VS with arbitrary capacities starting from address 0 and having one or more storage protection keys, the hardware In a virtual memory control method that eliminates the management of RS in software by primarily managing RS and VS in software, it guarantees the operation of existing programs that have limitations on the size of the operating address space. It is possible to expand virtual storage capacity and real storage capacity.

[Embodiments of the invention]

Next, embodiments of the present invention will be described in detail using the drawings.

Figure 1 is a diagram showing a directory in the present invention, and the size of each LVS is 16MB (i.e., 24MB).
This is an example in which the size (which can be represented by a bit address) is fixed.

VS indicates that LVSo is more similar to LVSn.

The directory 1 in the present invention consists of LVS directories 2 corresponding to each LVS,
Each LVS directory 2 consists of a plurality of directory entries 3 provided corresponding to a 4K byte memory area. Here, a 4K byte memory area is called a page. Directory entry 3 has a page address field 5 that stores the page number on the RS.

The correspondence between each LVS and VS is performed using an LVS number, and LVS switching is performed using a logical virtual space switching privileged command that specifies the LVS number issued by the OS. The number of the LVS being executed is stored on register 6.

The supervisor part of the OS operates on the LVS with LVS number 0, and the directory entry corresponding to the basic part of the supervisor is copied to the directory entry at the same relative position in all other LVS directories by the directory copy privileged command. each
Close communication between programs running on LVS and the supervisor is controlled. FIG. 2 shows a privileged command for directory copying in the present invention,
FIG. 3 shows the processing according to that command. The contents of the directory Doo to Dom corresponding to Lom from page Loo on LVS with LVS number 0 are transferred to all other
Directory entry Dno of directory for LVS
An example of copying from to Dnm is shown below.

The OP code contains a code that instructs copying, operand 1 indicates directory number 0, operand 2 indicates directory number m, and operand 3 indicates directory number 0 in the logical virtual space. It is shown that When this command is issued, the control program reads the directory from 0 to m in logical space number 0 and writes it to the directory from 0 to m in another logical space.

FIG. 3 shows a state in which copying has been completed. Directory 1 is stored in a specific area of RS4 in this embodiment. This may be done by providing a dedicated local memory and storing the information there. logical virtual space
Directories Doo to Dom corresponding to LVSo are all other logical virtual spaces LVSn Dno to Dnm
will be copied by. Therefore, in each LVS, Dno
When a memory access is performed at an address from to Dnm, Moo on RS is
Mom's area will be accessed from.

FIG. 4 is an example of address translation and its operation according to the present invention, and shows an example where logical virtual address A is associated with real address B by directory entry 3. be. FIG. 5 shows the hardware of the address translation unit that performs such address translation, and the operation will be explained below. Address register 8 is a register that stores a logical virtual address, and this register consists of a 12-bit page field 9 and a 12-bit displacement field 10. Address register 12 is a register that stores a virtual address, and this register is composed of a 12-bit page field 9 and a 12-bit displacement field 10. The page field 13 is composed of a bit displacement field 14. Address conversion from a logical virtual address to a real address begins with the LVS number 11 specified by the logical virtual space switching privileged instruction issued by the OS stored in register 6, page field 9 of address register 8, and Displacement fields 10 are joined to obtain a 31-bit virtual address in address register 12.
Next, page field 1 of address register 12
Directory entry 16 is created by adding 2 bits "0" to the lower part of 3 and adding the start address of directory 1 indicated by register 15 to it.
Get the address of. This directory entry 1
The page address field 5 of 6 is read out on the register 17, and the displacement field 14 of the address register 12 is connected to the lower part thereof to obtain a 31-bit real address.

In this example, the LVS capacity is fixed at 16MB and the RS capacity is 2GB.
Increasing the capacity to 16MB or more and increasing the RS capacity to 2GB or more can be easily done by expanding the address register and changing the directory. Note that the directory does not need to be on real memory as in this example.

〔Effect of the invention〕

With the configuration as described above, the following effects can be obtained by the present invention.

In a virtual memory control method that eliminates software management of real storage devices by primarily managing real storage devices and virtual memory using hardware, the operation of existing programs that have limitations on the size of the operating address space. Expansion of virtual and real memory beyond the capacity of the maximum address space in which existing programs can operate can be achieved with minimal hardware and software modifications, while guaranteeing the same performance.

[Brief explanation of drawings]

FIG. 1 is a system configuration diagram showing an embodiment of a directory according to the present invention, FIG. 2 is a diagram showing the structure of a command word according to an embodiment of the present invention, and FIG. 3 is a system configuration diagram showing an embodiment of a directory according to the present invention. FIG. 4 is a schematic configuration diagram for explaining address translation and its operation in an embodiment of the present invention, and FIG. 5 is a block diagram showing an embodiment of the present invention. . 1...Directory, 2...Logical virtual space (LVS)
Directory for, 3... Directory entry, 5
...Page address field, 6, 8, 12, 1
5, 17...Register, 7...Logic virtual space (LVS), 9,13...Page field, 10,
14...Displacement field, 11...Logical virtual space number (LVS#), Loo, Lom...Page, OP1, OP2,
OP3...operand, n...number of logical virtual spaces (1,
2,…)m…Page number (1, 2,…).

Claims (1)

[Claims] 1 In a virtual memory control method that has a directory for managing real storage and virtual memory in page units, and converts addresses from virtual addresses to real addresses by referencing the directory, a single virtual memory is divided into a plurality of logical virtual spaces each starting from address 0, and the directory corresponding to the single virtual memory is referenced based on information identifying the logical virtual space and an address on the logical virtual space. A virtual memory control method characterized by performing address translation from an address in a logical virtual space to an address in a real storage device.