On 06/12/2018 07:39 AM, Kirill A. Shutemov wrote: > Encrypted VMA will have KeyID stored in vma->vm_page_prot. This way we "An encrypted VMA..." > don't need to do anything special to setup encrypted page table entries > and don't need to reserve space for KeyID in a VMA. > > This patch changes _PAGE_CHG_MASK to include KeyID bits. Otherwise they > are going to be stripped from vm_page_prot on the first pgprot_modify(). > > Define PTE_PFN_MASK_MAX similar to PTE_PFN_MASK but based on > __PHYSICAL_MASK_SHIFT. This way we include whole range of bits > architecturally available for PFN without referencing physical_mask and > mktme_keyid_mask variables. > > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> > --- > arch/x86/include/asm/pgtable_types.h | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h > index 1e5a40673953..e8ebe760b88d 100644 > --- a/arch/x86/include/asm/pgtable_types.h > +++ b/arch/x86/include/asm/pgtable_types.h > @@ -121,8 +121,13 @@ > * protection key is treated like _PAGE_RW, for > * instance, and is *not* included in this mask since > * pte_modify() does modify it. > + * > + * 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) & ((1ULL << __PHYSICAL_MASK_SHIFT) - 1)) "signed long" is really unusual to see. Was that intentional? > +#define _PAGE_CHG_MASK (PTE_PFN_MASK_MAX | _PAGE_PCD | _PAGE_PWT | \ > _PAGE_SPECIAL | _PAGE_ACCESSED | _PAGE_DIRTY | \ > _PAGE_SOFT_DIRTY) > #define _HPAGE_CHG_MASK (_PAGE_CHG_MASK | _PAGE_PSE) This makes me a bit nervous. We have some places (here) where we pretend that the KeyID is part of the paddr and then other places like pte_pfn() where it's not. Seems like something that will come back to bite us.
