1. A method maintaining a fixed Quality of Service (QoS) for a Peripheral Component Interconnect Express (PCIe) device in relation to multiple hosts accessing the PCIe device, the method comprising: receiving commands from the hosts in PCIe function queues of the PCIe device; fetching the commands from the PCIe function command queues, queuing the commands according to a command arbitration policy established for the PCIe device, and storing the queued commands in an internal memory of the PCIe device; retrieving the queued commands from the internal memory in a sequence determined by applying a calculated QoS to at least one of the queued commands; and allocating PCIe device resources based on payload information corresponding to each one of the retrieved commands.