A computer implemented method for handling interrupts in a host system, the host system having processors for running guest operating systems - OS - on top of a hypervisor in a virtualized environment, wherein at least one of the guest OSes is operable in a non-real time and in a real-time mode of operation, wherein in non-real time mode operation interrupts for a first processor running the at least one guest OS are handled by the hypervisor, and wherein in real-time mode operation the at least one guest OS is pinned to the first processor and interrupts for the first processor are directly routed to the at least one guest OS instead of being processed by the hypervisor, the method characterized by comprising: generating, by the at least one guest OS, a signal to enter real-time mode operation when a real-time application is running or is to be run by the guest OS; identifying, by the hypervisor, the signal indicating real-time mode operation for the at least one guest OS; in response to the signal, clearing a bit in a virtual machine control structure - VMCS - that indicates an external interrupt is to generate a virtual machine - VM - exit wherein a transition from execution by the guest OS to execution by a host system occurs, such that during real-time mode of operation an interrupt for the first processor running the at least one guest OS is directly routed to the guest OS while the guest OS is running without causing a transition from execution of instructions by the guest OS to execution of instructions by the hypervisor. wherein at least one of the guest OSes is operable in a non-real time and in a real-time mode of operation, wherein in non-real time mode operation interrupts for a first processor running the at least one guest OS are handled by the hypervisor, and wherein in real-time mode operation the at least one guest OS is pinned to the first processor and interrupts for the first processor are directly routed to the at least one guest OS instead of being processed by the hypervisor, the method characterized by comprising: wherein in non-real time mode operation interrupts for a first processor running the at least one guest OS are handled by the hypervisor, and wherein in real-time mode operation the at least one guest OS is pinned to the first processor and interrupts for the first processor are directly routed to the at least one guest OS instead of being processed by the hypervisor, the method characterized by comprising: generating, by the at least one guest OS, a signal to enter real-time mode operation when a real-time application is running or is to be run by the guest OS; identifying, by the hypervisor, the signal indicating real-time mode operation for the at least one guest OS; in response to the signal, clearing a bit in a virtual machine control structure - VMCS - that indicates an external interrupt is to generate a virtual machine - VM - exit wherein a transition from execution by the guest OS to execution by a host system occurs, such that during real-time mode of operation an interrupt for the first processor running the at least one guest OS is directly routed to the guest OS while the guest OS is running without causing a transition from execution of instructions by the guest OS to execution of instructions by the hypervisor.