Switching apparatus and method for link initialization in a shared I/O environment

• US 7,917,658 B2
• Filed: 05/25/2008
• Issued: 03/29/2011
• Est. Priority Date: 01/21/2003
• Status: Expired due to Fees

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Emulex Design & Manufacturing Corp. (Broadcom, Inc.)
• Inventors: Khan, Asif, Pagan, Annette, Utley, Robert Haskell, Pekkala, Richard E., Pettey, Christopher J.
• Primary Examiner(s): Hafiz; Tariq
• Assistant Examiner(s): SUN, SCOTT C
• Application Number:
  US12/126,891
• Publication Number:
  US 20080288664A1
• Time in Patent Office: 1,038 Days
• Field of Search: None
• US Class Current: 710/2
• CPC Class Codes: H04L 12/4633 Interconnection of networks using encapsulation techniques, e.g. tunneling

Abstract

An apparatus and method are provided that enable I/O devices to be shared among multiple operating system domains. The apparatus has a first plurality of I/O ports, a second I/O port, and link training logic. The first plurality of I/O ports is coupled to a plurality of operating system domains through a load-store fabric. Each of the first plurality of I/O ports is configured to route transactions between the plurality of operating system domains and the switching apparatus. The second I/O port is coupled to a first shared input/output endpoint. The first shared input/output endpoint is configured to request/complete the transactions for each of the plurality of operating system domains. The link training logic is coupled to the second I/O port. The link training logic initializes a link between the second I/O port and the first shared input/output endpoint to support the transactions corresponding to the each of the plurality of operating system domains. The link is initialized in a manner that is transparent to the plurality of operating system domains.

Claims

1. A shared I/O apparatus, comprising:

a shared I/O endpoint, configured to request/complete transactions for each of a plurality of operating system domains, wherein said each of a plurality of operating system domains communicate with said shared I/O endpoint according to a protocol that provides for routing of transactions only for a single operating system domain, said shared I/O endpoint comprising;

a first I/O port, coupled to a link, configured to request/complete said transactions for each of said plurality of operating system domains according to a variant of said protocol, wherein said variant comprises encapsulating an OS domain header within a transaction layer packet that otherwise comports with said protocol, and wherein a particular OS domain header associates a particular transaction layer packet with a particular one of said plurality of operating system domains; and

link training logic, coupled to said first I/O port, configured to initialize said link, wherein said link is initialized in a manner that is transparent to said plurality of operating system domains.

2. The shared I/O apparatus as recited in claim 1, wherein said link training logic employs a mechanism according to said protocol to initialize said link, and wherein said mechanism would otherwise be ignored by a non-shared input/output endpoint, and wherein said shared input/output endpoint recognizes said mechanism.

3. The shared I/O apparatus as recited in claim 2, wherein the shared input/output endpoint provides a count indicating a number of said plurality of operating system domains that said shared input/output endpoint is capable of supporting.

4. The shared I/O apparatus as recited in claim 2, wherein said protocol comprises the PCI Express protocol, and wherein said mechanism comprises a PCI Express data link layer packet that is undefined.

5. The shared I/O apparatus as recited in claim 1, wherein said shared input/output endpoint is configured to associate each of said transactions with a corresponding one of said plurality of operating system domains (OSDs), said corresponding one of said plurality of OSDs corresponding to one or more root complexes.

6. The shared I/O apparatus as recited in claim 1, wherein said link is initialized without any intervention by system software.

7. The shared I/O apparatus as recited in claim 6, wherein said system software comprises operating systems, basic input/output systems (BIOS), configuration applications, and management applications.

8. A root complex apparatus, comprising:

a root complex, wherein said root complex corresponds to a plurality of operating system domains, and wherein each of said plurality of operating system domains communicate with a shared I/O endpoint according to a protocol that provides for routing of transactions only for a single operating system domain, said root complex comprising;

a first I/O port, coupled to a link, configured to request/complete said transactions for each of said plurality of operating system domains according to a variant of said protocol, wherein said variant comprises encapsulating an OS domain header within a transaction layer packet that otherwise comports with said protocol, and wherein a particular OS domain header associates a particular transaction layer packet with a particular one of said plurality of operating system domains; and

link training logic, coupled to said first I/O port, configured to initialize said link, wherein said link is initialized in a manner that is transparent to said plurality of operating system domains.

9. The root complex apparatus as recited in claim 8, wherein said link training logic employs a mechanism according to said protocol to initialize said link, and wherein said mechanism would otherwise be ignored by a second root complex that corresponds to a single operating system domain, and wherein said root complex recognizes said mechanism.

10. The root complex apparatus as recited in claim 9, wherein said root complex provides a count indicating a number of the plurality of operating system domains that said root complex is capable of supporting.

11. The root complex apparatus as recited in claim 9, wherein said protocol comprises the PCI Express protocol, and wherein said mechanism comprises a PCI Express data link layer packet that is undefined.

12. The root complex apparatus as recited in claim 8, wherein said root complex is configured to associate each of said transactions with a corresponding one of said plurality of operating system domains (OSDs).

13. The root complex apparatus as recited in claim 8, wherein said link is initialized without any intervention by system software.

14. The root complex apparatus as recited in claim 13, wherein said system software comprises operating systems, basic input/output systems (BIOS), configuration applications, and management applications.