On Sun, Mar 06, 2022 at 02:15:32AM +0200, Jarkko Sakkinen wrote: > On Sat, Mar 05, 2022 at 05:19:24AM +0200, Jarkko Sakkinen wrote: > > Sorry, I missed this. > > > > On Thu, Mar 03, 2022 at 01:44:14PM -0800, Dave Hansen wrote: > > > On 3/3/22 13:23, Reinette Chatre wrote: > > > > Unfortunately MAP_POPULATE is not supported by SGX VMAs because of their > > > > VM_IO and VM_PFNMAP flags. When VMAs with such flags obtain this capability > > > > then I believe that SGX would benefit. > > > > > > Some Intel folks asked for this quite a while ago. I think it's > > > entirely doable: add a new vm_ops->populate() function that will allow > > > ignoring VM_IO|VM_PFNMAP if present. > > > > I'm sorry what I don't understand what you mean by ignoring here, > > i.e. cannot fully comprehend the last sentece. > > > > And would the vm_ops->populate() be called right after the existing ones > > involved with the VMA creation process? > > > > > Or, if nobody wants to waste all of the vm_ops space, just add an > > > arch_vma_populate() or something which can call over into SGX. > > > > > > I'll happily review the patches if anyone can put such a beast together. > > > > I'll start with vm_ops->populate() and check the feedback first for > > that. > > I would instead extend populate() in file_operations into: > > int (*populate)(struct file *, struct vm_area_struct *, bool populate); > > This does not add to memory consumption. Ugh, mixing my words, sorry :-) I meant: int (*mmap)(struct file *, struct vm_area_struct *, bool populate); BR, Jarkko
