In vfio I have some questions.
1. How can I disable the access by mmap?
We can disable all access to vfio fd by returning a EAGAIN error
if user try to access it during the reset period until the host
reset finished.
But about the bar region which is maped by vfio_pci_mmap.
How can I disable it in vfio driver?
Even there is a way to do it,
how about the complexity to recovery the mmap?
That's exactly the "sticky point" I refer to above, you'd need to
solve that problem. MST would probably still argue that we don't need
to disable all those interfaces, a userspace driver can already do
things like disable mmio space and then attempt to read from the mmio
space of the device.