On Mon, Aug 19, 2024, Jason Gunthorpe wrote: > On Fri, Aug 16, 2024 at 07:56:30PM +0200, David Hildenbrand wrote: > > > I think KVM does something nasty: if it something with a "struct page", and > > it's not PageReserved, it would take a reference (if I get > > kvm_pfn_to_refcounted_page()) independent if it's a "normal" or "not normal" > > page -- it essentially ignores the vm_normal_page() information in the page > > tables ... > > Oh that's nasty. Nothing should be upgrading the output of the follow > functions to refcounted. That's what GUP is for. > > And PFNMAP pages, even if they have struct pages for some reason, > should *NEVER* be refcounted because they are in a PFNMAP VMA. That is > completely against the whole point :\ If they could be safely > refcounted then it would be a MIXEDMAP. Yeah yeah, I'm working on it. https://lore.kernel.org/all/20240726235234.228822-1-seanjc@xxxxxxxxxx
