A method for reducing address space in a shared virtualized I/O device includes allocating hardware resources including variable resources and permanent resources, to one or more functions. The method also includes allocating address space for an I/O mapping of the resources in a system memory, and assigning a respective portion of that address space for each function. The method further includes assigning space within each respective portion for variable resources available for allocation to the function to which the respective portion is assigned, and further assigning space within each respective portion for a set of permanent resources that have been allocated to the function to which the respective portion is assigned. The method further includes providing a translation table having a plurality of entries, and storing within each entry of the translation table, a different internal address of a permanent resource that has been allocated to a particular function.