Dirty Page Tracking of Guest-Uncached Memory

A system for providing a dirty bitmap to an application executable in a host machine, comprising:

• a first region of memory that stores an internal dirty bitmap indicating whether a guest executable in a host machine has updated one or more pages in guest memory of the guest since a previously received request for a snapshot of the internal dirty bitmap;
• a hypervisor that receives a request for a snapshot of the internal dirty bitmap, wherein the request is from an application that communicates with the hypervisor;
• and
• a dirty memory manager that copies a set of bits of the internal dirty bitmap into a shared dirty bitmap stored at a second region of memory, sets each bit in the internal dirty bitmap having a first value to a second value, invalidates all cache lines in a set of pages corresponding to one or more bits having the first value in the shared dirty bitmap, and provides the shared dirty bitmap to the application after the cache lines in the set of pages have been invalidated,
• wherein the second region of memory is accessible by the hypervisor and application.

A machine-readable medium comprising a plurality of machine-readable instructions that when executed by one or more processors is adapted to cause the one or more processors to perform a method comprising:

• receiving, by a hypervisor executable in a host machine, a request for a snapshot of an internal dirty bitmap stored at a first region of memory, the request being from an application that communicates with the hypervisor, and the internal dirty bitmap indicating whether a guest executable in the host machine has updated one or more pages in guest memory of the guest since a previously received request for a snapshot of the internal dirty bitmap;
• copying a set of bits of the internal dirty bitmap into a shared dirty bitmap, the shared dirty bitmap being stored at a second region of memory and accessible by the hypervisor and application;
• for each bit of the set of bits having a first value, setting the respective bit to a second value;
• invalidating all cache lines in a set of pages corresponding to one or more bits having the first value in the shared dirty bitmap;
• and
• after the invalidating, providing the shared dirty bitmap to the application.