| Message ID | 20230629205040.665834-3-axelrasmussen@google.com |
|---|---|
| State | New |
| Headers | show |
| Series | [v2,1/6] mm: userfaultfd: add new UFFDIO_POISON ioctl | expand |
On Thu, Jun 29, 2023 at 01:50:37PM -0700, Axel Rasmussen wrote: > The behavior here is the same as it is for anon/shmem. This is done > separately because hugetlb pte marker handling is a bit different. > > Signed-off-by: Axel Rasmussen <axelrasmussen@google.com> > --- > mm/hugetlb.c | 33 +++++++++++++++++++++++++++++++-- > mm/userfaultfd.c | 6 +----- > 2 files changed, 32 insertions(+), 7 deletions(-) > > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > index 38711d49e4db..05abe88986b6 100644 > --- a/mm/hugetlb.c > +++ b/mm/hugetlb.c > @@ -6090,14 +6090,24 @@ vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, > } > > entry = huge_ptep_get(ptep); > - /* PTE markers should be handled the same way as none pte */ > - if (huge_pte_none_mostly(entry)) > + if (huge_pte_none_mostly(entry)) { > + if (is_pte_marker(entry)) { > + unsigned long marker = pte_marker_get(pte_to_swp_entry(entry)); > + > + if (marker & PTE_MARKER_UFFD_POISON) { > + ret = VM_FAULT_HWPOISON_LARGE; > + goto out_mutex; > + } > + } > /* > + * Other PTE markers should be handled the same way as none PTE. > + * > * hugetlb_no_page will drop vma lock and hugetlb fault > * mutex internally, which make us return immediately. > */ > return hugetlb_no_page(mm, vma, mapping, idx, address, ptep, > entry, flags); > + } > > ret = 0; > > @@ -6253,6 +6263,25 @@ int hugetlb_mfill_atomic_pte(pte_t *dst_pte, > int writable; > bool folio_in_pagecache = false; > > + if (uffd_flags_mode_is(flags, MFILL_ATOMIC_POISON)) { > + ptl = huge_pte_lock(h, dst_mm, dst_pte); > + > + /* Don't overwrite any existing PTEs (even markers) */ > + if (!huge_pte_none(huge_ptep_get(dst_pte))) { > + spin_unlock(ptl); > + return -EEXIST; > + } > + > + _dst_pte = make_pte_marker(PTE_MARKER_UFFD_POISON); > + set_huge_pte_at(dst_mm, dst_addr, dst_pte, _dst_pte); > + > + /* No need to invalidate - it was non-present before */ > + update_mmu_cache(dst_vma, dst_addr, dst_pte); > + > + spin_unlock(ptl); > + return 0; > + } > + > if (is_continue) { > ret = -EFAULT; > folio = filemap_lock_folio(mapping, idx); > diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c > index 87b62ca1e09e..4436cae1c7a8 100644 > --- a/mm/userfaultfd.c > +++ b/mm/userfaultfd.c > @@ -381,12 +381,8 @@ static __always_inline ssize_t mfill_atomic_hugetlb( > * supported by hugetlb. A PMD_SIZE huge pages may exist as used > * by THP. Since we can not reliably insert a zero page, this > * feature is not supported. > - * > - * PTE marker handling for hugetlb is a bit special, so for now > - * UFFDIO_POISON is not supported. > */ > - if (uffd_flags_mode_is(flags, MFILL_ATOMIC_ZEROPAGE) || > - uffd_flags_mode_is(flags, MFILL_ATOMIC_POISON)) { > + if (uffd_flags_mode_is(flags, MFILL_ATOMIC_ZEROPAGE)) { > mmap_read_unlock(dst_mm); > return -EINVAL; If we have the last patch declaring the feature bits and so on, IIUC we don'tt need this change back and forth. Other than that looks good. Thanks, > } > -- > 2.41.0.255.g8b1d071c50-goog >
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 38711d49e4db..05abe88986b6 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -6090,14 +6090,24 @@ vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, } entry = huge_ptep_get(ptep); - /* PTE markers should be handled the same way as none pte */ - if (huge_pte_none_mostly(entry)) + if (huge_pte_none_mostly(entry)) { + if (is_pte_marker(entry)) { + unsigned long marker = pte_marker_get(pte_to_swp_entry(entry)); + + if (marker & PTE_MARKER_UFFD_POISON) { + ret = VM_FAULT_HWPOISON_LARGE; + goto out_mutex; + } + } /* + * Other PTE markers should be handled the same way as none PTE. + * * hugetlb_no_page will drop vma lock and hugetlb fault * mutex internally, which make us return immediately. */ return hugetlb_no_page(mm, vma, mapping, idx, address, ptep, entry, flags); + } ret = 0; @@ -6253,6 +6263,25 @@ int hugetlb_mfill_atomic_pte(pte_t *dst_pte, int writable; bool folio_in_pagecache = false; + if (uffd_flags_mode_is(flags, MFILL_ATOMIC_POISON)) { + ptl = huge_pte_lock(h, dst_mm, dst_pte); + + /* Don't overwrite any existing PTEs (even markers) */ + if (!huge_pte_none(huge_ptep_get(dst_pte))) { + spin_unlock(ptl); + return -EEXIST; + } + + _dst_pte = make_pte_marker(PTE_MARKER_UFFD_POISON); + set_huge_pte_at(dst_mm, dst_addr, dst_pte, _dst_pte); + + /* No need to invalidate - it was non-present before */ + update_mmu_cache(dst_vma, dst_addr, dst_pte); + + spin_unlock(ptl); + return 0; + } + if (is_continue) { ret = -EFAULT; folio = filemap_lock_folio(mapping, idx); diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c index 87b62ca1e09e..4436cae1c7a8 100644 --- a/mm/userfaultfd.c +++ b/mm/userfaultfd.c @@ -381,12 +381,8 @@ static __always_inline ssize_t mfill_atomic_hugetlb( * supported by hugetlb. A PMD_SIZE huge pages may exist as used * by THP. Since we can not reliably insert a zero page, this * feature is not supported. - * - * PTE marker handling for hugetlb is a bit special, so for now - * UFFDIO_POISON is not supported. */ - if (uffd_flags_mode_is(flags, MFILL_ATOMIC_ZEROPAGE) || - uffd_flags_mode_is(flags, MFILL_ATOMIC_POISON)) { + if (uffd_flags_mode_is(flags, MFILL_ATOMIC_ZEROPAGE)) { mmap_read_unlock(dst_mm); return -EINVAL; }
The behavior here is the same as it is for anon/shmem. This is done separately because hugetlb pte marker handling is a bit different. Signed-off-by: Axel Rasmussen <axelrasmussen@google.com> --- mm/hugetlb.c | 33 +++++++++++++++++++++++++++++++-- mm/userfaultfd.c | 6 +----- 2 files changed, 32 insertions(+), 7 deletions(-)