A method, system, and article of manufacture to efficiently support interrupts of a computer system. A message-based interrupt from a device of the computer system is intercepted. A fake line-based interrupt for the device corresponding to the message-based interrupt is determined, wherein an operating system (OS) of the computer system is not message-based interrupt capable. The fake line-based interrupt is issued to the OS. A query from the OS regarding the fake line-based interrupt is serviced, the query to determine if the fake line-based interrupt was from the device. An interrupt vector associated with the message-based interrupt is provided to the OS.