[PATCH 13/13] vfio/type1: Mark follow_pfn as unsafe

[Jason Gunthorpe]

On Wed, Oct 07, 2020 at 08:14:06PM +0200, Daniel Vetter wrote:

> Hm, but wouldn't need that the semi-nasty vma_open trick to make sure
> that vma doesn't untimely disappear? Or is the idea to look up the
> underlying vfio object, and refcount that directly?

Ah, the patches Alex was working on had the refcount I think, it does
need co-ordination across multiple VFIO instances IIRC.

At least a simple check would guarentee we only have exposed PCI BAR
pages which is not as bad security wise as the other stuff.

Jason