On Fri, Aug 23, 2024 at 11:21:27PM +1000, Alexey Kardashevskiy wrote: > Currently private MMIO nested page faults are not expected so when such > fault occurs, KVM tries moving the faulted page from private to shared > which is not going to work as private MMIO is not backed by memfd. > > Handle private MMIO as shared: skip page state change and memfd This means host keeps the mapping for private MMIO, which is different from private memory. Not sure if it is expected, and I want to get some directions here.