Extended page table for i/o address translation

Patent metadata

Field	Value
Publication number	US-2015261688-A1
Application number	US-201414210968-A
Country	US
Kind code	A1
Filing date	Mar 14, 2014
Priority date	Mar 14, 2014
Publication date	Sep 17, 2015
Grant date	—

Abstract

An extension of a page table is provided. An aspect includes receiving, by a host bridge, a request. An aspect includes determining, by the host bridge, that access to a memory address space referenced by the request is authorized based on a requester identifier associated with the request. An aspect includes, based on determining that access to the memory address space is authorized, accessing, by the host bridge, a page included in the memory address space based on a combination of: a start of the page table and a single extended index.

First claim

1 - 15 . (canceled)

16 . A computer system for extending a page table, the system comprising:
a memory having computer readable instructions; and a processor configured to execute the computer readable instructions, the instructions comprising:
receiving a request;
determining that access to a memory address space referenced by the request is authorized based on a requester identifier associated with the request; and
based on determining that access to the memory address space is authorized, accessing a page included in the memory address space based on a combination of: a start of the page table, a first offset associated with the request that corresponds to a group of page table entries in the page table, and a second offset associated with the request that corresponds to an entry in the page table within the group and a single extended index.

17 . The computer system of claim 16 , wherein the instructions comprise:
determining that access to the memory address space is authorized based on a portion of an address associated with the request.

18 . The computer system of claim 16 , wherein the instructions comprise:
determining that the access to the memory address space referenced by the request is authorized based on determining that access controls within a device table entry permit access.

19 . The computer system of claim 16 , wherein the instructions comprise:
receiving the request from a switch associated with a peripheral component interconnect adapter.

20 . The computer system of claim 16 , wherein the memory address space is a direct memory access address space, and wherein the instructions comprise:
accessing the page included in the direct memory access address space based on determining that a format indicator indicates that extended translation is provided, and wherein the single extended index is based on a first offset associated with the request that corresponds to a group of page table entries in the page table and a second offset associated with the request that corresponds to an entry in the page table within the group.

Assignees

• IBM

Inventors

• Craddock David
• Gregg Thomas A
• Greiner Dan F
• Lais Eric N

Classifications

• G06F12/14

  Protection against unauthorised use of memory {or access to memory} · CPC title

• G06F2212/452

  Instruction code · CPC title

• G06F12/1081 Primary

  for peripheral access to main memory, e.g. direct memory access [DMA] · CPC title

• G06F2212/657

  Virtual address space management · CPC title

• G06F2212/284

  being distributed · CPC title