International Business Machines Corporation

James C Mazurowski

Leslie W Wyman

Roger E Hough

Kenneth J Oakes

Marten J Halma

Kenneth J Fredericks

Suzanne M John

Moon Jung Kim

Robert Edward Galbraith

Casper A Scalzi

Charles E Shapley

Peter H Gum

Donald W McCauley

Richard Roland Guyette

Richard Cwiakala

Assaf Marron

John Fenton Scanlon

Norman C Chou

David W Hollar

Miriam P Brown

Enables any OS of plural OSs within any of plural logical-resource partitions (LPARs) of a CEC to use interpretive execution for synchronously-executable CHSC (channel subsystem call) commands. A CHSC command authorization mask (CCAM) is provided to control which CHSC commands are allowed to execute interpretively (with pass-through), and which commands are executed with hypervisor intervention (as all prior CHSC commands did). By enabling interpretive execution of those commands which can successfully operate with pass-through, significant system efficiency is obtained. And by disabling interpretive execution for a subset of CHSC commands (which are not allowed to execute with pass-through) potential system failures may be prevented. Thus, interpretive execution may be restricted differently among the OSs in a CEC. Novel CHSC command execution now handles multiple images of shared I/O resources by use of image identifiers, which could not be done before. The information requested by any OS issuing a CHSC command is filtered and optionally compacted by the I/O subsystem responding to the command by only providing information obtained from control blocks associated with the OS which issued the command. This is done by having a set of control blocks for each I/O resource, each control block in the set being associated with a particular OS.

Pass-through for I/O channel subsystem call instructions for accessing

This invention involves reconfiguration support for shared I/O resources in a a computer electronic complex (CEC) supporting both shared and unshared I/O channels of the type described and claimed in U.S. patent application Ser. No. 07/898,867 (PO9-92-016) filed on the same day as the subject application and assigned to the same assignee as the subject application. Prior channel subsystem call (CHSC) instructions cannot execute when a channel is to be configured as shareable by plural operating systems in a CEC.

Asynchronous command support for shared channels for a computer complex

A CPU interface recognizing a large very number of I/O interruption queues in a logically partitioned data processing system. Different partitions may contain different guest operating systems. The CPU interface controls how plural CPUs respond to I/O interruptions put on numerous hardware-controlled queues. A host hypervisor program dispatches the guest operating systems. The guests use the I/O interruptions in controlling the dispatching of their programs on the CPUs in a system. The invention allows the number of guest partitions in the system to exceed the number of I/O interruption subclasses (ISCs) architected in the system, and enables the dispatching controls of each guest operating system to be sensitive to different priorities for plural programs operating under a respective guest. The invention provides CPU controls that support alerting the host to enabled I/O interruptions, and provides CPU controlled pass-through for enabling direct guest handling of the guests I/O interruptions.

CPU expansive gradation of I/O interruption subclass recognition

Growing community of inventors

Poughkeepsie, NY, United States of America

James C Mazurowski