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SubjectRe: [RFC, PATCH 16/22] x86/mm: Preserve KeyID on pte_modify() and pgprot_modify()
On Mon, Mar 05, 2018 at 11:09:23AM -0800, Dave Hansen wrote:
> On 03/05/2018 08:26 AM, Kirill A. Shutemov wrote:
> > + * It includes full range of PFN bits regardless if they were claimed for KeyID
> > + * or not: we want to preserve KeyID on pte_modify() and pgprot_modify().
> > */
> > -#define _PAGE_CHG_MASK (PTE_PFN_MASK | _PAGE_PCD | _PAGE_PWT | \
> > +#define PTE_PFN_MASK_MAX \
> > + (((signed long)PAGE_MASK) & ((1UL << __PHYSICAL_MASK_SHIFT) - 1))
> > +#define _PAGE_CHG_MASK (PTE_PFN_MASK_MAX | _PAGE_PCD | _PAGE_PWT | \
> > _PAGE_SPECIAL | _PAGE_ACCESSED | _PAGE_DIRTY | \
> > _PAGE_SOFT_DIRTY)
>
> Is there a way to make this:
>
> #define _PAGE_CHG_MASK (PTE_PFN_MASK | PTE_KEY_MASK...? | _PAGE_PCD |
>
> That would be a lot more understandable.

Yes, it would.

But it means we will have *two* variables referenced from _PAGE_CHG_MASK:
one for PTE_PFN_MASK and one for PTE_KEY_MASK as both of them are dynamic.

With this patch we would get rid of both of them.

I'll update the description.

--
Kirill A. Shutemov

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