Hardware assistance for page table coherence with guest page mappings

摘要

Some embodiments of the present invention include a memory management unit (MMU) configured to, in response to a write access targeting a guest page mapping of a guest virtual page number (GVPN) to a guest physical page number (GPPN) within a guest page table, identify a first page mapping that associates the GVPN with a physical page number (PPN). The MMU is also configured to determine whether a traced write indication is associated with the first page mapping and, if so, record update information identifying the targeted guest page mapping. The update information is used to reestablish coherence between the guest page mapping and the first page mapping. The MMU is further configured to perform the write access.

主权项

1. An apparatus comprising:
a hardware memory management unit configured to:
in response to a write access to a first guest virtual page number (GVPN), identify a first page mapping in a virtual-to-physical page mapping hierarchy corresponding to the first GVPN that maps to a first physical page number (PPN);determine whether a traced write indication is associated with the first page mapping, wherein such a traced write indication signifies that a memory page addressed by the PPN contains at least part of a guest page table, so that the write access would be to an entry of the guest page table, the entry of the guest page table providing a mapping for a second GVPN;record update information when a traced write indication is associated with the first page mapping, wherein the update information is later used to reestablish coherence between the entry of the guest page table and a second page mapping in the virtual-to-physical page mapping hierarchy, the second page mapping corresponding to the second GVPN and providing a mapping to a second PPN; andperform the write access.