1. A method for single-root input/output virtualization (SR-IOV) virtual functions sharing on one or more hosts, implemented in a management system connected to the one or more hosts by a transparent bridge device, comprising: simulating one or more simulated devices in the one or more hosts with each simulated device mapped to one of a plurality of SR-IOV virtual functions of a SR-IOV device; redirecting each of one or more configuration spaces from a corresponding one of the plurality of SR-IOV virtual functions to a corresponding one of the one or more simulated devices in the one or more hosts, through a non-transparent bridge (NTB) device in each of the one or more hosts, wherein the one or more hosts is connected with the transparent bridge device by the respective NTB device in each of the one or more hosts; redirecting each of one or more configuration space requests from the corresponding one of the one or more simulated devices to a corresponding SR-IOV virtual function of the corresponding one of the one or more simulated devices when the configuration space request is received by the corresponding one of the one or more simulated devices; and redirecting each of one or more memory access operations from the corresponding SR-IOV virtual function to a mapped memory on a corresponding host of the one or more hosts having the corresponding one of the one or more simulated devices; and redirecting each of one or more interrupts generated by one or more SR-IOV virtual machines hosted on the one or more hosts to the corresponding one of the one or more simulated devices, wherein each of the one or more hosts has an address space of the respective host and the management system has a corresponding direct memory access (DMA) descriptor for the one or more virtual functions of the corresponding host, and wherein a full range of a corresponding random access memory of the corresponding host in the address space of the respective host is all mapped into an unoccupied address space of the management system through the NTB device in each of the one or more hosts.