[PATCH v3 0/4] hugetlb: Disable huge pmd unshare for uffd-wp

Peter Xu
2021-02-18T21:54:42Z

v3:
- patch 4:
- fix build failure for !CMA and/or !HUGETLBFS [Axel]
- Fix mmu notifier range to use start/end [Mike]
- add more r-bs

v2:
- patch 4: move hugetlb_unshare_all_pmds() into mm/hugetlb.c, so it can be used
even outside userfaultfd.c

This series tries to disable huge pmd unshare of hugetlbfs backed memory for
uffd-wp. Although uffd-wp of hugetlbfs is still during rfc stage, the idea of
this series may be needed for multiple tasks (Axel's uffd minor fault series,
and Mike's soft dirty series), so I picked it out from the larger series.

References works:

Uffd shmem+hugetlbfs rfc:
https://lore.kernel.org/lkml/20210115170907.24498-1-peterx@redhat.com/

Uffd minor mode for hugetlbfs:
https://lore.kernel.org/lkml/20210212215403.3457686-1-axelrasmussen@google.com/

Soft dirty for hugetlbfs:
https://lore.kernel.org/lkml/20210211000322.159437-1-mike.kravetz@oracle.com/

Please review, thanks.

Peter Xu (4):
hugetlb: Pass vma into huge_pte_alloc() and huge_pmd_share()
hugetlb/userfaultfd: Forbid huge pmd sharing when uffd enabled
mm/hugetlb: Move flush_hugetlb_tlb_range() into hugetlb.h
hugetlb/userfaultfd: Unshare all pmds for hugetlbfs when register wp

arch/arm64/mm/hugetlbpage.c | 7 ++-
arch/ia64/mm/hugetlbpage.c | 3 +-
arch/mips/mm/hugetlbpage.c | 4 +-
arch/parisc/mm/hugetlbpage.c | 2 +-
arch/powerpc/mm/hugetlbpage.c | 3 +-
arch/s390/mm/hugetlbpage.c | 2 +-
arch/sh/mm/hugetlbpage.c | 2 +-
arch/sparc/mm/hugetlbpage.c | 1 +
fs/userfaultfd.c | 4 ++
include/linux/hugetlb.h | 18 ++++++-
include/linux/userfaultfd_k.h | 9 ++++
mm/hugetlb.c | 94 +++++++++++++++++++++++++++--------
mm/userfaultfd.c | 2 +-
13 files changed, 116 insertions(+), 35 deletions(-)

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2.26.2