Enhanced shadow page table algorithms are presented for enhancing typical page table algorithms. In a virtual machine environment, where an operating system may be running within a partition, the operating system maintains it's own guest page tables. These page tables are not the real page tables that map to the real physical memory. Instead, the memory is mapped by shadow page tables maintained by a virtualing program, such as a hypervisor, that virtualizes the partition containing the operating system. Enhanced shadow page table algorithms provide efficient ways to harmonize the shadow page tables and the guest page tables. Specifically, by using tagged translation lookaside buffers, batched shadow page table population, lazy flags, and cross-processor shoot downs, the algorithms make sure that changes in the guest pages tables are reflected in the shadow page tables.