When kernel sets up an encrypted page mapping, encryption KeyID is derived from a VMA. KeyID is going to be part of vma->vm_page_prot and it will be propagated transparently to page table entry on mk_pte().
But there is an exception: zero page is never encrypted and its mapping must use KeyID-0, regardless VMA's KeyID. Introduce helpers that create a page table entry for zero page. The generic implementation will be overridden by architecture-specific code that takes care about using correct KeyID. Signed-off-by: Kirill A. Shutemov <[email protected]> --- fs/dax.c | 3 +-- include/asm-generic/pgtable.h | 8 ++++++++ mm/huge_memory.c | 6 ++---- mm/memory.c | 3 +-- mm/userfaultfd.c | 3 +-- 5 files changed, 13 insertions(+), 10 deletions(-) diff --git a/fs/dax.c b/fs/dax.c index a237141d8787..6ecc9c560e62 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -1445,8 +1445,7 @@ static vm_fault_t dax_pmd_load_hole(struct xa_state *xas, struct vm_fault *vmf, pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable); mm_inc_nr_ptes(vma->vm_mm); } - pmd_entry = mk_pmd(zero_page, vmf->vma->vm_page_prot); - pmd_entry = pmd_mkhuge(pmd_entry); + pmd_entry = mk_zero_pmd(zero_page, vmf->vma->vm_page_prot); set_pmd_at(vmf->vma->vm_mm, pmd_addr, vmf->pmd, pmd_entry); spin_unlock(ptl); trace_dax_pmd_load_hole(inode, vmf, zero_page, *entry); diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h index 75d9d68a6de7..afcfbb4af4b2 100644 --- a/include/asm-generic/pgtable.h +++ b/include/asm-generic/pgtable.h @@ -879,8 +879,16 @@ static inline unsigned long my_zero_pfn(unsigned long addr) } #endif +#ifndef mk_zero_pte +#define mk_zero_pte(addr, prot) pte_mkspecial(pfn_pte(my_zero_pfn(addr), prot)) +#endif + #ifdef CONFIG_MMU +#ifndef mk_zero_pmd +#define mk_zero_pmd(zero_page, prot) pmd_mkhuge(mk_pmd(zero_page, prot)) +#endif + #ifndef CONFIG_TRANSPARENT_HUGEPAGE static inline int pmd_trans_huge(pmd_t pmd) { diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 1334ede667a8..e9a791413730 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -678,8 +678,7 @@ static bool set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm, pmd_t entry; if (!pmd_none(*pmd)) return false; - entry = mk_pmd(zero_page, vma->vm_page_prot); - entry = pmd_mkhuge(entry); + entry = mk_zero_pmd(zero_page, vma->vm_page_prot); if (pgtable) pgtable_trans_huge_deposit(mm, pmd, pgtable); set_pmd_at(mm, haddr, pmd, entry); @@ -2109,8 +2108,7 @@ static void __split_huge_zero_page_pmd(struct vm_area_struct *vma, for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { pte_t *pte, entry; - entry = pfn_pte(my_zero_pfn(haddr), vma->vm_page_prot); - entry = pte_mkspecial(entry); + entry = mk_zero_pte(haddr, vma->vm_page_prot); pte = pte_offset_map(&_pmd, haddr); VM_BUG_ON(!pte_none(*pte)); set_pte_at(mm, haddr, pte, entry); diff --git a/mm/memory.c b/mm/memory.c index e2bb51b6242e..81ae8c39f75b 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2970,8 +2970,7 @@ static vm_fault_t do_anonymous_page(struct vm_fault *vmf) /* Use the zero-page for reads */ if (!(vmf->flags & FAULT_FLAG_WRITE) && !mm_forbids_zeropage(vma->vm_mm)) { - entry = pte_mkspecial(pfn_pte(my_zero_pfn(vmf->address), - vma->vm_page_prot)); + entry = mk_zero_pte(vmf->address, vma->vm_page_prot); vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address, &vmf->ptl); if (!pte_none(*vmf->pte)) diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c index c7ae74ce5ff3..06bf4ea3ee05 100644 --- a/mm/userfaultfd.c +++ b/mm/userfaultfd.c @@ -120,8 +120,7 @@ static int mfill_zeropage_pte(struct mm_struct *dst_mm, pgoff_t offset, max_off; struct inode *inode; - _dst_pte = pte_mkspecial(pfn_pte(my_zero_pfn(dst_addr), - dst_vma->vm_page_prot)); + _dst_pte = mk_zero_pte(dst_addr, dst_vma->vm_page_prot); dst_pte = pte_offset_map_lock(dst_mm, dst_pmd, dst_addr, &ptl); if (dst_vma->vm_file) { /* the shmem MAP_PRIVATE case requires checking the i_size */ -- 2.21.0
