From: Peter Xu <peterx@redhat.com>
To: linux-kernel@vger.kernel.org, linux-mm@kvack.org
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>,
Jerome Glisse <jglisse@redhat.com>,
Mike Kravetz <mike.kravetz@oracle.com>,
Matthew Wilcox <willy@infradead.org>,
Andrew Morton <akpm@linux-foundation.org>,
Axel Rasmussen <axelrasmussen@google.com>,
Hugh Dickins <hughd@google.com>,
peterx@redhat.com, Nadav Amit <nadav.amit@gmail.com>,
Andrea Arcangeli <aarcange@redhat.com>,
Mike Rapoport <rppt@linux.vnet.ibm.com>
Subject: [PATCH 16/23] hugetlb/userfaultfd: Take care of UFFDIO_COPY_MODE_WP
Date: Mon, 22 Mar 2021 20:49:05 -0400 [thread overview]
Message-ID: <20210323004912.35132-17-peterx@redhat.com> (raw)
In-Reply-To: <20210323004912.35132-1-peterx@redhat.com>
Firstly, pass the wp_copy variable into hugetlb_mcopy_atomic_pte() thoughout
the stack. Then, apply the UFFD_WP bit if UFFDIO_COPY_MODE_WP is with
UFFDIO_COPY. Introduce huge_pte_mkuffd_wp() for it.
Note that similar to how we've handled shmem, we'd better keep setting the
dirty bit even if UFFDIO_COPY_MODE_WP is provided, so that the core mm will
know this page contains valid data and never drop it.
Signed-off-by: Peter Xu <peterx@redhat.com>
---
include/asm-generic/hugetlb.h | 5 +++++
include/linux/hugetlb.h | 6 ++++--
mm/hugetlb.c | 22 +++++++++++++++++-----
mm/userfaultfd.c | 12 ++++++++----
4 files changed, 34 insertions(+), 11 deletions(-)
diff --git a/include/asm-generic/hugetlb.h b/include/asm-generic/hugetlb.h
index 8e1e6244a89d..548212eccbd6 100644
--- a/include/asm-generic/hugetlb.h
+++ b/include/asm-generic/hugetlb.h
@@ -27,6 +27,11 @@ static inline pte_t huge_pte_mkdirty(pte_t pte)
return pte_mkdirty(pte);
}
+static inline pte_t huge_pte_mkuffd_wp(pte_t pte)
+{
+ return pte_mkuffd_wp(pte);
+}
+
static inline pte_t huge_pte_modify(pte_t pte, pgprot_t newprot)
{
return pte_modify(pte, newprot);
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index a7f7d5f328dc..ef8d2b8427b1 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -141,7 +141,8 @@ int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm, pte_t *dst_pte,
unsigned long dst_addr,
unsigned long src_addr,
enum mcopy_atomic_mode mode,
- struct page **pagep);
+ struct page **pagep,
+ bool wp_copy);
#endif /* CONFIG_USERFAULTFD */
bool hugetlb_reserve_pages(struct inode *inode, long from, long to,
struct vm_area_struct *vma,
@@ -321,7 +322,8 @@ static inline int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm,
unsigned long dst_addr,
unsigned long src_addr,
enum mcopy_atomic_mode mode,
- struct page **pagep)
+ struct page **pagep,
+ bool wp_copy)
{
BUG();
return 0;
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index def2c7ddf3ae..f0e55b341ebd 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -4725,7 +4725,8 @@ int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm,
unsigned long dst_addr,
unsigned long src_addr,
enum mcopy_atomic_mode mode,
- struct page **pagep)
+ struct page **pagep,
+ bool wp_copy)
{
bool is_continue = (mode == MCOPY_ATOMIC_CONTINUE);
struct address_space *mapping;
@@ -4822,17 +4823,28 @@ int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm,
hugepage_add_new_anon_rmap(page, dst_vma, dst_addr);
}
- /* For CONTINUE on a non-shared VMA, don't set VM_WRITE for CoW. */
- if (is_continue && !vm_shared)
+ /*
+ * For either: (1) CONTINUE on a non-shared VMA, or (2) UFFDIO_COPY
+ * with wp flag set, don't set pte write bit.
+ */
+ if (wp_copy || (is_continue && !vm_shared))
writable = 0;
else
writable = dst_vma->vm_flags & VM_WRITE;
_dst_pte = make_huge_pte(dst_vma, page, writable);
- if (writable)
- _dst_pte = huge_pte_mkdirty(_dst_pte);
+ /*
+ * Always mark UFFDIO_COPY page dirty; note that this may not be
+ * extremely important for hugetlbfs for now since swapping is not
+ * supported, but we should still be clear in that this page cannot be
+ * thrown away at will, even if write bit not set.
+ */
+ _dst_pte = huge_pte_mkdirty(_dst_pte);
_dst_pte = pte_mkyoung(_dst_pte);
+ if (wp_copy)
+ _dst_pte = huge_pte_mkuffd_wp(_dst_pte);
+
set_huge_pte_at(dst_mm, dst_addr, dst_pte, _dst_pte);
(void)huge_ptep_set_access_flags(dst_vma, dst_addr, dst_pte, _dst_pte,
diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
index 0963e0d9ed20..78471ae3d25c 100644
--- a/mm/userfaultfd.c
+++ b/mm/userfaultfd.c
@@ -207,7 +207,8 @@ static __always_inline ssize_t __mcopy_atomic_hugetlb(struct mm_struct *dst_mm,
unsigned long dst_start,
unsigned long src_start,
unsigned long len,
- enum mcopy_atomic_mode mode)
+ enum mcopy_atomic_mode mode,
+ bool wp_copy)
{
int vm_alloc_shared = dst_vma->vm_flags & VM_SHARED;
int vm_shared = dst_vma->vm_flags & VM_SHARED;
@@ -304,7 +305,8 @@ static __always_inline ssize_t __mcopy_atomic_hugetlb(struct mm_struct *dst_mm,
}
err = hugetlb_mcopy_atomic_pte(dst_mm, dst_pte, dst_vma,
- dst_addr, src_addr, mode, &page);
+ dst_addr, src_addr, mode, &page,
+ wp_copy);
mutex_unlock(&hugetlb_fault_mutex_table[hash]);
i_mmap_unlock_read(mapping);
@@ -406,7 +408,8 @@ extern ssize_t __mcopy_atomic_hugetlb(struct mm_struct *dst_mm,
unsigned long dst_start,
unsigned long src_start,
unsigned long len,
- enum mcopy_atomic_mode mode);
+ enum mcopy_atomic_mode mode,
+ bool wp_copy);
#endif /* CONFIG_HUGETLB_PAGE */
static __always_inline ssize_t mfill_atomic_pte(struct mm_struct *dst_mm,
@@ -527,7 +530,8 @@ static __always_inline ssize_t __mcopy_atomic(struct mm_struct *dst_mm,
*/
if (is_vm_hugetlb_page(dst_vma))
return __mcopy_atomic_hugetlb(dst_mm, dst_vma, dst_start,
- src_start, len, mcopy_mode);
+ src_start, len, mcopy_mode,
+ wp_copy);
if (!vma_is_anonymous(dst_vma) && !vma_is_shmem(dst_vma))
goto out_unlock;
--
2.26.2
next prev parent reply other threads:[~2021-03-23 0:50 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-23 0:48 [PATCH 00/23] userfaultfd-wp: Support shmem and hugetlbfs Peter Xu
2021-03-23 0:48 ` [PATCH 01/23] shmem/userfaultfd: Take care of UFFDIO_COPY_MODE_WP Peter Xu
2021-03-23 0:48 ` [PATCH 02/23] mm: Clear vmf->pte after pte_unmap_same() returns Peter Xu
2021-03-23 2:34 ` Miaohe Lin
2021-03-23 15:40 ` Peter Xu
2021-03-23 0:48 ` [PATCH 03/23] mm/userfaultfd: Introduce special pte for unmapped file-backed mem Peter Xu
2021-03-23 0:48 ` [PATCH 04/23] mm/swap: Introduce the idea of special swap ptes Peter Xu
2021-03-23 0:48 ` [PATCH 05/23] shmem/userfaultfd: Handle uffd-wp special pte in page fault handler Peter Xu
2021-03-23 0:48 ` [PATCH 06/23] mm: Drop first_index/last_index in zap_details Peter Xu
2021-03-23 0:48 ` [PATCH 07/23] mm: Introduce zap_details.zap_flags Peter Xu
2021-03-23 2:11 ` Matthew Wilcox
2021-03-23 15:43 ` Peter Xu
2021-03-23 0:48 ` [PATCH 08/23] mm: Introduce ZAP_FLAG_SKIP_SWAP Peter Xu
2021-03-23 0:48 ` [PATCH 09/23] mm: Pass zap_flags into unmap_mapping_pages() Peter Xu
2021-03-23 0:48 ` [PATCH 10/23] shmem/userfaultfd: Persist uffd-wp bit across zapping for file-backed Peter Xu
2021-03-23 0:49 ` [PATCH 11/23] shmem/userfaultfd: Allow wr-protect none pte for file-backed mem Peter Xu
2021-03-23 0:49 ` [PATCH 12/23] shmem/userfaultfd: Allows file-back mem to be uffd wr-protected on thps Peter Xu
2021-03-23 0:49 ` [PATCH 13/23] shmem/userfaultfd: Handle the left-overed special swap ptes Peter Xu
2021-03-23 0:49 ` [PATCH 14/23] shmem/userfaultfd: Pass over uffd-wp special swap pte when fork() Peter Xu
2021-03-23 0:49 ` [PATCH 15/23] hugetlb/userfaultfd: Hook page faults for uffd write protection Peter Xu
2021-04-21 22:02 ` Mike Kravetz
2021-03-23 0:49 ` Peter Xu [this message]
2021-04-21 23:06 ` [PATCH 16/23] hugetlb/userfaultfd: Take care of UFFDIO_COPY_MODE_WP Mike Kravetz
2021-04-22 1:14 ` Peter Xu
2021-03-23 0:49 ` [PATCH 17/23] hugetlb/userfaultfd: Handle UFFDIO_WRITEPROTECT Peter Xu
2021-04-22 18:22 ` Mike Kravetz
2021-03-23 0:49 ` [PATCH 18/23] mm/hugetlb: Introduce huge version of special swap pte helpers Peter Xu
2021-04-22 19:00 ` Mike Kravetz
2021-03-23 0:50 ` [PATCH 19/23] hugetlb/userfaultfd: Handle uffd-wp special pte in hugetlb pf handler Peter Xu
2021-04-22 22:45 ` Mike Kravetz
2021-04-26 2:08 ` Peter Xu
2021-03-23 0:50 ` [PATCH 20/23] hugetlb/userfaultfd: Allow wr-protect none ptes Peter Xu
2021-04-23 0:08 ` Mike Kravetz
2021-03-23 0:50 ` [PATCH 21/23] hugetlb/userfaultfd: Only drop uffd-wp special pte if required Peter Xu
2021-04-23 20:33 ` Mike Kravetz
2021-04-26 21:16 ` Peter Xu
2021-04-26 21:36 ` Mike Kravetz
2021-04-26 22:05 ` Peter Xu
2021-04-26 23:09 ` Mike Kravetz
2021-03-23 0:50 ` [PATCH 22/23] mm/userfaultfd: Enable write protection for shmem & hugetlbfs Peter Xu
2021-03-23 0:50 ` [PATCH 23/23] userfaultfd/selftests: Enable uffd-wp for shmem/hugetlbfs Peter Xu
2021-03-23 0:54 ` [PATCH 00/23] userfaultfd-wp: Support shmem and hugetlbfs Peter Xu
2021-04-21 16:03 ` Peter Xu
2021-04-21 21:39 ` Mike Kravetz
2021-04-22 1:16 ` Peter Xu
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