The subject matter of this specification can be implemented in, among other things, a method that includes identifying an assigned device that is assigned to a guest operating system of a virtual machine. The method includes transmitting, to the guest operating system, a request indicating a failover event. The failover event involves a switch from the assigned device to an emulated device. The assigned device and the emulated device share a backend physical device. The method further includes receiving an acknowledgement message from the guest operating system that it is ready to switch from the assigned device to the emulated device. The method further includes preventing access to the assigned device by the guest operating system. The method further includes associating a device driver of a hypervisor with the backend physical device and providing a notification to the guest operating system that the emulated device is available for use.
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