Dirty tracking pages

[emesare]

For more information this issue in vm-memory has relevant context: rust-vmm/vm-memory#140.

[emesare]

MSHV actually already provides this via https://learn.microsoft.com/en-us/virtualization/api/hypervisor-platform/funcs/whvquerygparangedirtybitmap

We just need to set the flag when mapping in the memory we want to track:

To use this function for a given address range, that address range must be mapped with WHvMapGpaRange, specifying the WHvMapGpaRangeFlagTrackDirtyPages flag.

Which corresponds to

windows-hypervisor/src/flags.rs

Line 54 in 96e5d85

const TrackDirtyPages = 0x8;