The patch titled
Subject: mm/hugetlb: handle UFFDIO_WRITEPROTECT
has been added to the -mm tree. Its filename is
mm-hugetlb-handle-uffdio_writeprotect.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-hugetlb-handle-uffdio_writeprotect.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-hugetlb-handle-uffdio_writeprotect.patch
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The -mm tree is included into linux-next and is updated
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------------------------------------------------------
From: Peter Xu <peterx@xxxxxxxxxx>
Subject: mm/hugetlb: handle UFFDIO_WRITEPROTECT
This starts from passing cp_flags into hugetlb_change_protection() so
hugetlb will be able to handle MM_CP_UFFD_WP[_RESOLVE] requests.
huge_pte_clear_uffd_wp() is introduced to handle the case where the
UFFDIO_WRITEPROTECT is requested upon migrating huge page entries.
Link: https://lkml.kernel.org/r/20220405014906.14708-1-peterx@xxxxxxxxxx
Signed-off-by: Peter Xu <peterx@xxxxxxxxxx>
Reviewed-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Alistair Popple <apopple@xxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Axel Rasmussen <axelrasmussen@xxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Jerome Glisse <jglisse@xxxxxxxxxx>
Cc: "Kirill A . Shutemov" <kirill@xxxxxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx>
Cc: Nadav Amit <nadav.amit@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/hugetlb.h | 6 ++++--
mm/hugetlb.c | 13 ++++++++++++-
mm/mprotect.c | 3 ++-
mm/userfaultfd.c | 8 ++++++++
4 files changed, 26 insertions(+), 4 deletions(-)
--- a/include/linux/hugetlb.h~mm-hugetlb-handle-uffdio_writeprotect
+++ a/include/linux/hugetlb.h
@@ -211,7 +211,8 @@ struct page *follow_huge_pgd(struct mm_s
int pmd_huge(pmd_t pmd);
int pud_huge(pud_t pud);
unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
- unsigned long address, unsigned long end, pgprot_t newprot);
+ unsigned long address, unsigned long end, pgprot_t newprot,
+ unsigned long cp_flags);
bool is_hugetlb_entry_migration(pte_t pte);
void hugetlb_unshare_all_pmds(struct vm_area_struct *vma);
@@ -397,7 +398,8 @@ static inline void move_hugetlb_state(st
static inline unsigned long hugetlb_change_protection(
struct vm_area_struct *vma, unsigned long address,
- unsigned long end, pgprot_t newprot)
+ unsigned long end, pgprot_t newprot,
+ unsigned long cp_flags)
{
return 0;
}
--- a/mm/hugetlb.c~mm-hugetlb-handle-uffdio_writeprotect
+++ a/mm/hugetlb.c
@@ -6207,7 +6207,8 @@ long follow_hugetlb_page(struct mm_struc
}
unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
- unsigned long address, unsigned long end, pgprot_t newprot)
+ unsigned long address, unsigned long end,
+ pgprot_t newprot, unsigned long cp_flags)
{
struct mm_struct *mm = vma->vm_mm;
unsigned long start = address;
@@ -6217,6 +6218,8 @@ unsigned long hugetlb_change_protection(
unsigned long pages = 0;
bool shared_pmd = false;
struct mmu_notifier_range range;
+ bool uffd_wp = cp_flags & MM_CP_UFFD_WP;
+ bool uffd_wp_resolve = cp_flags & MM_CP_UFFD_WP_RESOLVE;
/*
* In the case of shared PMDs, the area to flush could be beyond
@@ -6263,6 +6266,10 @@ unsigned long hugetlb_change_protection(
entry = make_readable_migration_entry(
swp_offset(entry));
newpte = swp_entry_to_pte(entry);
+ if (uffd_wp)
+ newpte = pte_swp_mkuffd_wp(newpte);
+ else if (uffd_wp_resolve)
+ newpte = pte_swp_clear_uffd_wp(newpte);
set_huge_swap_pte_at(mm, address, ptep,
newpte, huge_page_size(h));
pages++;
@@ -6277,6 +6284,10 @@ unsigned long hugetlb_change_protection(
old_pte = huge_ptep_modify_prot_start(vma, address, ptep);
pte = huge_pte_modify(old_pte, newprot);
pte = arch_make_huge_pte(pte, shift, vma->vm_flags);
+ if (uffd_wp)
+ pte = huge_pte_mkuffd_wp(huge_pte_wrprotect(pte));
+ else if (uffd_wp_resolve)
+ pte = huge_pte_clear_uffd_wp(pte);
huge_ptep_modify_prot_commit(vma, address, ptep, old_pte, pte);
pages++;
}
--- a/mm/mprotect.c~mm-hugetlb-handle-uffdio_writeprotect
+++ a/mm/mprotect.c
@@ -460,7 +460,8 @@ unsigned long change_protection(struct m
BUG_ON((cp_flags & MM_CP_UFFD_WP_ALL) == MM_CP_UFFD_WP_ALL);
if (is_vm_hugetlb_page(vma))
- pages = hugetlb_change_protection(vma, start, end, newprot);
+ pages = hugetlb_change_protection(vma, start, end, newprot,
+ cp_flags);
else
pages = change_protection_range(tlb, vma, start, end, newprot,
cp_flags);
--- a/mm/userfaultfd.c~mm-hugetlb-handle-uffdio_writeprotect
+++ a/mm/userfaultfd.c
@@ -705,6 +705,7 @@ int mwriteprotect_range(struct mm_struct
atomic_t *mmap_changing)
{
struct vm_area_struct *dst_vma;
+ unsigned long page_mask;
struct mmu_gather tlb;
pgprot_t newprot;
int err;
@@ -742,6 +743,13 @@ int mwriteprotect_range(struct mm_struct
if (!vma_is_anonymous(dst_vma))
goto out_unlock;
+ if (is_vm_hugetlb_page(dst_vma)) {
+ err = -EINVAL;
+ page_mask = vma_kernel_pagesize(dst_vma) - 1;
+ if ((start & page_mask) || (len & page_mask))
+ goto out_unlock;
+ }
+
if (enable_wp)
newprot = vm_get_page_prot(dst_vma->vm_flags & ~(VM_WRITE));
else
_
Patches currently in -mm which might be from peterx@xxxxxxxxxx are
mm-introduce-pte_marker-swap-entry.patch
mm-teach-core-mm-about-pte-markers.patch
mm-check-against-orig_pte-for-finish_fault.patch
mm-uffd-pte_marker_uffd_wp.patch
mm-shmem-take-care-of-uffdio_copy_mode_wp.patch
mm-shmem-handle-uffd-wp-special-pte-in-page-fault-handler.patch
mm-shmem-persist-uffd-wp-bit-across-zapping-for-file-backed.patch
mm-shmem-allow-uffd-wr-protect-none-pte-for-file-backed-mem.patch
mm-shmem-allows-file-back-mem-to-be-uffd-wr-protected-on-thps.patch
mm-shmem-handle-uffd-wp-during-fork.patch
mm-hugetlb-introduce-huge-pte-version-of-uffd-wp-helpers.patch
mm-hugetlb-hook-page-faults-for-uffd-write-protection.patch
mm-hugetlb-take-care-of-uffdio_copy_mode_wp.patch
mm-hugetlb-handle-uffdio_writeprotect.patch
mm-hugetlb-handle-pte-markers-in-page-faults.patch
mm-hugetlb-allow-uffd-wr-protect-none-ptes.patch
mm-hugetlb-only-drop-uffd-wp-special-pte-if-required.patch
mm-hugetlb-handle-uffd-wp-during-fork.patch
mm-khugepaged-dont-recycle-vma-pgtable-if-uffd-wp-registered.patch
mm-pagemap-recognize-uffd-wp-bit-for-shmem-hugetlbfs.patch
mm-uffd-enable-write-protection-for-shmem-hugetlbfs.patch
mm-enable-pte-markers-by-default.patch
selftests-uffd-enable-uffd-wp-for-shmem-hugetlbfs.patch
