On 12/9/2015 7:28 PM, Michael S. Tsirkin wrote:

I remember reading that it's possible to implement a bus driver
on windows if required.  But basically I don't see how windows can be
relevant to discussing guest driver patches. That discussion
probably belongs on the qemu maling list, not on lkml.

I am not sure whether we can write a bus driver for Windows to support
migration. But I think device vendor who want to support migration will 
improve their driver if we provide such framework in the
hypervisor which just need them to change their driver.