APPARATUS AND METHOD FOR EMULATING AN I/O INSTRUCTION FOR THE CORRECT PROCESSOR AND FOR SERVICING SOFTWARE SMI'S IN A MULTI-PROCESSOR ENVIRONMENT

A method for controlling I/O in a multi-processor environment, comprising the steps of: determining if an I/O instruction requiring an interrupt is being executed by one of the processors in the multi-processor environment to transfer data or a command between the processor and an I/O device; performing an interrupt if such an I/O instruction is detected; determining which of the processors in the multi-processor environment is executing an I/O instruction; if only one of the processors is executing an I/O instruction, setting a Last Processor indicator designating that one processor as the processor executing the I/O instruction; and transferring data or a command between the processor designated in the Last Processor indicator and the I/O device in response to the I/O instruction. In a further aspect of the invention, a method is provided for servicing a software system management interrupt (SMI) initiated by an I/O instruction in a multi-processor environment, comprising the steps of: detecting the occurrence of a software SMI; determining which processor in the multi-processor environment has save state information indicating that that processor initiated the software SMI; and transferring information between an SMI handler and the processor determined to have initiated the software SMI.