x86/hugetlb: use set_pmd for huge pte operations
PATCH 1/1 x86/hugetlb: use set_pmd for huge pte operations
From: Dave McCracken <[email protected]>
On x86, a huge pte is logically a pte, but structurally a pmd. Among other issues, pmds and ptes overload some flags for multiple uses (PAT vs PSE), so it is necessary to know which structural level a pagetable entry is in order interpret it properly.
When huge pages are used within a paravirtualized system, it is therefore appropriate to use the pmd set of function to operate on them, so that the hypervisor can correctly validate the update.
Signed-off-by Dave McCracken <[email protected]>
Signed-off-by Jeremy Fitzhardinge <[email protected]>
arch/x86/include/asm/hugetlb.h +22 -8
@@ -36,16 +36,24 @@ static inline void hugetlb_free_pgd_range(struct mmu_gather *tlb,free_pgd_range (tlb, addr, end, floor, ceiling); } +static inline pte_t huge_ptep_get (pte_t *ptep) +{ +return *ptep; +} +static inline void set_huge_pte_at (struct mm_struct *mm,unsigned long addr,pte_t *ptep,pte_t pte) { -set_pte_at (mm, addr, ptep, pte); +set_pmd ((pmd_t *)ptep,__pmd (pte_val (pte))); }static inline pte_t huge_ptep_get_and_clear (struct mm_struct *mm,unsigned long addr,pte_t *ptep) { -return ptep_get_and_clear (mm, addr, ptep); +pte_t pte =huge_ptep_get (ptep); + +set_huge_pte_at (mm, addr, ptep,__pte (0 )); +return pte; } static inline void huge_ptep_clear_flush(struct vm_area_struct *vma,
@@ -66,19 +74,25 @@ static inline pte_t huge_pte_wrprotect(pte_t pte)static inline void huge_ptep_set_wrprotect (struct mm_struct *mm,unsigned long addr,pte_t *ptep) { -ptep_set_wrprotect (mm, addr, ptep); +pte_t pte =huge_ptep_get (ptep); + + pte =pte_wrprotect (pte); +set_huge_pte_at (mm, addr, ptep, pte); }static inline int huge_ptep_set_access_flags (struct vm_area_struct *vma,unsigned long addr,pte_t *ptep,pte_t pte,int dirty) { -return ptep_set_access_flags (vma, addr, ptep, pte, dirty); -} +pte_t oldpte =huge_ptep_get (ptep); +int changed = !pte_same (oldpte, pte); -static inline pte_t huge_ptep_get (pte_t *ptep) -{ -return *ptep; +if (changed && dirty) { +set_huge_pte_at (vma->vm_mm, addr, ptep, pte); +flush_tlb_page (vma, addr); + } + +return changed; }static inline int arch_prepare_hugepage (struct page *page)