Create a dual boot with an already existing windows partition

For the past few months I had an ubuntu with main OS and a windows 11 that I used with kvm/qemu. The whole data is on a distinct partition. Now I want to switch back to a dual boot with windows and ubuntu but I do not want to lose the data I had on my windows. Is there a way to add a windows entrypoint in grub to point to the windows partition ?

Thank you in advance !