Converting a message signaled interruption into an I/O adapter event notification

A computer program product for managing interruption requests in a computing environment, the computer program product comprising:

• a non-transitory computer readable storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method comprising:
• based on executing a register interruptions operation of a Modify PCI Function Controls (MPFC) instruction that specifies a function handle of an adapter, specifying a location in system memory of an adapter interruption bit vector (AIBV) of the adapter, the AIBV included in an array of one or more AIBVs, and a location in system memory of an adapter interruption summary bit (AISB) of an AISB array;
• receiving from the adapter a request for interruption;
• and
• based on the received request, setting, by an input/output (I/O) hub coupled to the adapter, an indicator in the AIBV indicating a type of event from the adapter and setting the AISB indicating an indicator is set in the AIBV, wherein the setting the indicator in the AIBV comprises:
• determining whether a vector number provided in the request is within a number of interruptions allowed for the adapter;
• and
• based on determining the vector number is within the allowed number of interruptions, using the vector number, an AIBV offset, and an AIBV address to determine the indicator in the AIBV to be set.