Messages in this thread | | | Date | Fri, 15 Jun 2018 16:14:17 +0300 | From | "Kirill A. Shutemov" <> | Subject | Re: [PATCHv3 08/17] x86/mm: Implement vma_is_encrypted() and vma_keyid() |
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On Wed, Jun 13, 2018 at 06:18:05PM +0000, Dave Hansen wrote: > On 06/12/2018 07:39 AM, Kirill A. Shutemov wrote: > > +bool vma_is_encrypted(struct vm_area_struct *vma) > > +{ > > + return pgprot_val(vma->vm_page_prot) & mktme_keyid_mask; > > +} > > + > > +int vma_keyid(struct vm_area_struct *vma) > > +{ > > + pgprotval_t prot; > > + > > + if (!vma_is_anonymous(vma)) > > + return 0; > > + > > + prot = pgprot_val(vma->vm_page_prot); > > + return (prot & mktme_keyid_mask) >> mktme_keyid_shift; > > +} > > Why do we have a vma_is_anonymous() in one of these but not the other?
It shouldn't be there. It's from earlier approach to the function. I'll fix this.
And I'll drop vma_is_encrypted(). It is not very useful.
> While this reuse of ->vm_page_prot is cute, is there any downside? It's > the first place I know of that we can't derive ->vm_page_prot from > ->vm_flags on non-VM_IO/PFNMAP VMAs. Is that a problem?
I don't think so.
It need to be covered in pte_modify() and such, but it's about it.
That's relatively isolated change and we can move KeyID into a standalone field, if this approach proves to be problematic.
-- Kirill A. Shutemov
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