System, method, and storage medium for shared key index space for memory regions

• US 20060095690A1
• Filed: 10/29/2004
• Published: 05/04/2006
• Est. Priority Date: 10/29/2004
• Status: Abandoned Application

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Gregg, Thomas A., Schmidt, Donald W., Craddock, David F.
• Application Number:
  US10/977,780
• Publication Number:
  US 20060095690A1
• Time in Patent Office: Days
• US Class Current: 711/153
• CPC Class Codes: G06F 12/1081 for peripheral access to main memory, e.g. direct memory access [DMA]
• CPC Class Codes: G06F 12/1475 in a virtual system, e.g. with translation means

Abstract

In a logical partitioning (LPAR) environment with InfiniBand™ host channel adapters (HCAs), multiple operating systems share the resources of a physical HCA. A mechanism for efficiently allocating memory regions (or memory windows) to different LPARs is provided, while ensuring that a memory region assigned to one LPAR is not accessible from another LPAR.

Claims

1. A method of providing shared key index spaces for memory regions, comprising:

associating a group of memory regions to a logical partition (LPAR) using a first portion of a key index, each memory region being associated with an RDMA-capable adapter, the LPAR being one of at least one LPARs; and

providing a single pointer for locating an entry in a protection table to an operating system running in the LPAR, the entry defining characteristics of the memory region.

2. The method of claim 1, further comprising:

receiving a request from the operating system for a group of memory regions;

determining which LPAR the operating system is running in;

initializing the entry in a protection table page table;

returning a group of keys.

3. The method of claim 1, further comprising:

registering a memory region in the group of memory regions with the RDMA-capable adapter.

4. The method of claim 1, further comprising:

allocating a memory region within the group to a consumer process by the operating system.

5. A system for providing shared key index spaces for memory regions, comprising:

a system memory having a protection table for each logical partition (LPAR);

an adapter having a protection table page table, the protection table page table being indexable by a key index to locate an entry in the protection table, the entry defining characteristics of a memory region or a memory window associated with the adapter;

wherein the adapter is shared by a plurality of operating systems running in different LPARs.

6. The system of claim 5, wherein the key index includes a page table index, a page index, and a key instance.

7. The system of claim 5, wherein the entries include a page pointer, a valid indication, a LPAR identifier, and a memory region control.

8. The system of claim 5, wherein the adapter is a host channel adapter.

9. The system of claim 5, wherein the adapter is a RDMA enabled network interface card (RNIC).

10. The system of claim 5, wherein the characteristics include one of more of the following:

length, starting address, access rights, and a reference to at least one address translation table.

11. The system of claim 5, wherein the protection table has 4K pages and each entry occupies 64 bytes so that each page holds 64 entries.

12. The system of claim 5, wherein the adapter provides a single pointer to a group of memory regions to one of the operating systems upon request.

13. A data structure for providing shared key index spaces for memory regions, comprising:

a key index having a protection table index, a page index, and a key instance; and

a protection table page table having a plurality of rows, each of the rows having a page pointer, a valid indication, a logical partition (LPAR) identifier (ID), and a memory region control;

wherein an entry associated with a memory region is located in a protection table in a system memory by using the key index and the protection table page table, the entry including characteristics of the memory region, the system memory having at least one LPARs, each LPARs running an operating system, the operating systems sharing a host channel adapter, the host channel adapter storing the protection table page table.

14. A computer-readable medium having instructions stored thereon to perform a method of locating a memory region, the method comprising:

receiving a packet on a link, the packet including a key index; and

locating an entry in a protection table for a particular logical partition (LPAR) by using the key index and a protection table page table, the entry including characteristics of a memory region.