Approaches for performing memory management by a hypervisor. A host operating system and a hypervisor are executed on a device. The host operating system is not configured to access physical memory addressed above four gigabytes. The hypervisor manages memory for a device, including memory addressed above four gigabytes. When the hypervisor instantiates a virtual machine, the hypervisor may allocate memory pages for the newly instantiated virtual machine by preferentially using any unassigned memory addressed above four gigabytes before using memory allocated from the host (and hence addressed below four gigabytes).