Arm Limited

Haralds Capkevics

Timothy Nicholas Hay

Nathan William Whitaker

An apparatus comprises an interrupt distributor to distribute virtual interrupts to one or more physical processors, each virtual interrupt to be handled by one of a plurality of virtual processors mappable to said one or more physical processors; and control circuitry to maintain virtual processor interrupt tracking information corresponding to a given virtual processor. The virtual processor interrupt tracking information includes a pending interrupt record tracking which types of virtual interrupts are pending for the given virtual processor, and separate from the pending interrupt record, a pending interrupt status indication indicating a pending interrupt status for the given virtual processor. The pending interrupt status indicates whether the number of pending virtual interrupts for the given virtual processor is zero.

Virtual processor interrupt tracking

Virtual processors are mappable to a number of physical processors. An interrupt distributor is responsible for distributing interrupt requests to a subset of the physical processors. An interface communicates with further interrupt distributors responsible for other physical processors. In response to an interrupt request to be handled by a target virtual processor, the interrupt distributor determines, based on cached virtual processor mapping information, whether to route the interrupt request to one of the subset of physical processors or to one of the further interrupt distributors. When a rejection response is received in response to an interrupt request routed to one of the further interrupt distributors, an update of the cached virtual processing mapping information is requested based on shared virtual processor mapping information, and a resent interrupt request is sent to a further interrupt distributor determined based on the shared virtual processor mapping information.

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Cambridge, United Kingdom

Haralds Capkevics