On Tue, Mar 12, 2024 at 07:11:18PM +0100, David Hildenbrand wrote: > PAT handling won't do the right thing in COW mappings: the first PTE > (or, in fact, all PTEs) can be replaced during write faults to point at > anon folios. Reliably recovering the correct PFN and cachemode using > follow_phys() from PTEs will not work in COW mappings. I guess the first question is: Why do we want to support COW mappings of VM_PAT areas? What breaks if we just disallow it?
