The "normal" way to debug a Qemu/KVM windows virtual machine at kernel-level (e.g., for writing a windows driver) is to use 2 windows VMs. One (called server) in which to run the kernel you are going to debug and one (called client or host) in which to run the debug tools.
(If you want to try this way, the instructions here have worked for me at least).
Several people have wondered if it is possible to save (at least some of) the memory overhead of the host/client VM by using wine instead to run the debug tools (from the Linux host). Unfortunately this seems to be harder than it seems.