On Tue, Aug 05, 2025 at 10:26:06AM +0800, Xu Yilun wrote: > > IMHO there is no use case for that, it should arguably be global to > > the whole kernel. > > I think there are 2 topics here: > > 1. Prevent VFIO mmap > 2. Prevent /sys/../resource, /dev/mem users > > I assume you are refering to the 2nd, then I agree. Yes, the region stuff is only about #2. > > > > > The original purpose of this pci_region_request_*() is to prevent > > > further mmap/read/write against a vfio_cdev FD which would be used > > > > No way, the VFIO internal mmap should be controled by VFIO not by > > I assume your point is never to use more than one request region in the > same driver to achieve some mutual exclusion. I'm good to it. We could > switch to some bound flag. Yes and yes > > The only thing request region should do is prevent /sys/../resource, > > /dev/mem users and so on, which is why it can and should be > > global. Arguably VFIO should always block those things but > > historically hasn't.. > > Agree. So seems no need a global option? I'd ask Alex if he is OK with a global behavior change to make vfio exclusive, after any required fixing to make vfio only request the regions once at driver probe time.. Jason
