System for determining adapter interrupt status where interrupt is sent to host after operating status stored in register is shadowed to host memory

摘要

An I/O adapter connects an I/O adapter to an I/O bus and includes a device interrupt status register and an interrupt status shadow address register. The device interrupt status register stores the interrupt status of the I/O adapter. The I/O adapter accesses the interrupt status shadow address register to determine an address of main memory at which the device interrupt status register is shadowed. After shadowing the interrupt status, the I/O adapter interrupts the processor complex which may then access local, main memory to determine the interrupt status. A multifunction I/O adapter permits a plurality of I/O adapters to be connected thereto and includes a function interrupt status register to summarize the interrupt status of all the I/O adapters attached thereto. After shadowing the summarized interrupt status, the multifunction I/O adapter interrupts the processor complex which may then access local, main memory to determine the interrupt status.