1. A virtualization management method for managing hardware resources of a communication device comprising an inter-board Hypervisor running on a hardware layer of a control board, comprising: allocating, by the inter-board Hypervisor, a first hardware resource which is freed at a hardware layer of a first service board deployed in a communication device, to a first virtual machine running on an intra-board Hypervisor in a second service board deployed in the communication device when one of the following situations occurs: the first service board is instructed to migrate resources to free the first hardware resource at the hardware layer of the first service board when it is detected that the current hardware resource usage of a hardware layer of the second service board exceeds a first threshold; the first service board is instructed to migrate resources to free the first hardware resource at the hardware layer of the first service board when a first hardware resource alarm instruction issued by the second service board is acquired and it is determined that the current hardware resource usage of the hardware layer of the first service board is lower than a second threshold, wherein the first hardware resource alarm instruction is issued by the second service board after the current hardware resource usage of the hardware layer of the second service board exceeds a first threshold, which is higher than, lower than, or equal to the second threshold; and a first hardware resource alarm instruction issued by the second service board is acquired and it is determined that the hardware layer of the first service board currently has the first hardware resource which is freed, wherein the first hardware resource alarm instruction is issued by the second service board after the current hardware resource usage of the hardware layer of the second service board exceeds a first threshold; acquiring, by the inter-board Hypervisor, a first virtual machine context that is issued by the first service board and that corresponds to a first interrupt, or a second virtual machine context that is obtained based on the first virtual machine context and a determined employer, wherein the first virtual machine context is issued by the first service board after the first service board determines that the first hardware resource generating the first interrupt at the hardware layer of the first service board is an allocated hardware resource in response to the first interrupt generated at the hardware layer of the first service board; and issuing, by the inter-board Hypervisor, the first virtual machine context, or the second virtual machine context, so that the second service board transfers the first virtual machine context or the second virtual machine context to the first virtual machine for processing on the intra-board Hypervisor in the second service board deployed in the communication device.