Hello, I'd like to see the subject implemented. It could be done like vmware's cbt the only thing is that it's called dirty bitmap here:
https://qemu-project.gitlab.io/qemu/interop/bitmaps.html

after that proxmox VE, RHEL Virt and opensource oVirt, and standard virtualization in linux. Also, AWS and some other cloud vendors use kvm maybe the dirty bitmap info available over the API.