Various embodiments of the present invention are directed to augmented interrupt controllers (AICs) and to synthetic interrupt sources (SISs) providing richer interrupt information (or "synthetic interrupts" or "SIs"). The AIC and SIS provide efficient means for sending and receiving interrupts, and particularly interrupts sent to and received by virtual machines. Several of these embodiments are specifically directed to an interrupt controller that is extended to accept and deliver additional information associated with an incoming interrupt. For certain such embodiments, a memory-mapped extension to the interrupt controller includes a data structure that is populated with the additional information as part of the interrupt delivery. Although several of the embodiments described herein are disclosed in the context of a virtual machine system, the inventions disclosed herein can also be applied to traditional computer systems (without a virtualization layer) as well.