1. A method, comprising: mapping, by a hypervisor being executed by a processing device of a host computer system, a plurality of interrupt controller registers of the host computer system into a memory address space of a virtual machine being executed by the host computer system; mapping, into the memory address space of the virtual machine, a task mapping data structure comprising a plurality of records, each record associating a task with a processor of the host computer system, wherein each record comprises a validity attribute; and mapping, into the memory address space of the virtual machine, a notification code module to be invoked by the virtual machine for evaluating the validity attribute, writing a notification message into an interrupt controller register associated with the processor identified using the task mapping data structure, and performing a virtual machine exit responsive to determining that the validity attribute associated with a task to receive the notification is invalid.