Patent ID: 8234432

Claim:
A method comprising: storing a data structure in memory in a system on which a plurality of guests are executable, the data structure storing at least an interrupt request state for each destination in each of the plurality of guests, and wherein the interrupt request state identifies which interrupts have been requested at the corresponding interrupt controller in the corresponding guest of the plurality of guests; receiving an interrupt message targeted at a first destination in a first guest of the plurality of guests; and updating, in the data structure, the interrupt request state that corresponds to the first destination and the first guest to record the interrupt identified in the interrupt message in the interrupt request state for the first destination and first guest, and wherein each interrupt has an associated delivery mode, wherein the data structure includes a first section corresponding to a first delivery mode and a second section corresponding to a second delivery mode, and wherein the interrupt request state for each destination and guest comprises data stored in each of the first section and the second section, and wherein updating the interrupt request state comprises writing an indication of the interrupt to a selected one of the first section and the second section responsive to the associated delivery mode.