From: Peter Xu <peterx@redhat.com>
To: linux-mm@kvack.org, linux-kernel@vger.kernel.org
Cc: Nadav Amit <nadav.amit@gmail.com>,
Miaohe Lin <linmiaohe@huawei.com>,
Mike Rapoport <rppt@linux.vnet.ibm.com>,
Andrea Arcangeli <aarcange@redhat.com>,
Hugh Dickins <hughd@google.com>,
peterx@redhat.com, Jerome Glisse <jglisse@redhat.com>,
Mike Kravetz <mike.kravetz@oracle.com>,
Jason Gunthorpe <jgg@ziepe.ca>,
Matthew Wilcox <willy@infradead.org>,
Andrew Morton <akpm@linux-foundation.org>,
Axel Rasmussen <axelrasmussen@google.com>,
"Kirill A . Shutemov" <kirill@shutemov.name>
Subject: [PATCH v2 23/24] mm/userfaultfd: Enable write protection for shmem & hugetlbfs
Date: Tue, 27 Apr 2021 12:13:16 -0400 [thread overview]
Message-ID: <20210427161317.50682-24-peterx@redhat.com> (raw)
In-Reply-To: <20210427161317.50682-1-peterx@redhat.com>
We've had all the necessary changes ready for both shmem and hugetlbfs. Turn
on all the shmem/hugetlbfs switches for userfaultfd-wp.
Now we can remove the flags parameter for vma_can_userfault() since not used
any more. Meanwhile, we can expand UFFD_API_RANGE_IOCTLS_BASIC with
_UFFDIO_WRITEPROTECT too because all existing types now support write
protection mode.
Since vma_can_userfault() will be used elsewhere, move into userfaultfd_k.h.
Signed-off-by: Peter Xu <peterx@redhat.com>
---
fs/userfaultfd.c | 19 -------------------
include/linux/userfaultfd_k.h | 15 +++++++++++++++
include/uapi/linux/userfaultfd.h | 7 +++++--
mm/userfaultfd.c | 10 +++-------
4 files changed, 23 insertions(+), 28 deletions(-)
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index a41e0631af512..a436a1feb10db 100644
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -1275,25 +1275,6 @@ static __always_inline int validate_range(struct mm_struct *mm,
return 0;
}
-static inline bool vma_can_userfault(struct vm_area_struct *vma,
- unsigned long vm_flags)
-{
- /* FIXME: add WP support to hugetlbfs and shmem */
- if (vm_flags & VM_UFFD_WP) {
- if (is_vm_hugetlb_page(vma) || vma_is_shmem(vma))
- return false;
- }
-
- if (vm_flags & VM_UFFD_MINOR) {
- /* FIXME: Add minor fault interception for shmem. */
- if (!is_vm_hugetlb_page(vma))
- return false;
- }
-
- return vma_is_anonymous(vma) || is_vm_hugetlb_page(vma) ||
- vma_is_shmem(vma);
-}
-
static int userfaultfd_register(struct userfaultfd_ctx *ctx,
unsigned long arg)
{
diff --git a/include/linux/userfaultfd_k.h b/include/linux/userfaultfd_k.h
index fefebe6e96560..95afd4814ab29 100644
--- a/include/linux/userfaultfd_k.h
+++ b/include/linux/userfaultfd_k.h
@@ -16,6 +16,7 @@
#include <linux/fcntl.h>
#include <linux/mm.h>
#include <asm-generic/pgtable_uffd.h>
+#include <linux/hugetlb_inline.h>
/* The set of all possible UFFD-related VM flags. */
#define __VM_UFFD_FLAGS (VM_UFFD_MISSING | VM_UFFD_WP | VM_UFFD_MINOR)
@@ -132,6 +133,20 @@ static inline bool userfaultfd_armed(struct vm_area_struct *vma)
return vma->vm_flags & __VM_UFFD_FLAGS;
}
+static inline bool vma_can_userfault(struct vm_area_struct *vma,
+ unsigned long vm_flags)
+{
+ if (vm_flags & VM_UFFD_MINOR) {
+ /* FIXME: Add minor fault interception for shmem. */
+ if (!is_vm_hugetlb_page(vma))
+ return false;
+ }
+
+ return vma_is_anonymous(vma) || is_vm_hugetlb_page(vma) ||
+ vma_is_shmem(vma);
+}
+
+
extern int dup_userfaultfd(struct vm_area_struct *, struct list_head *);
extern void dup_userfaultfd_complete(struct list_head *);
diff --git a/include/uapi/linux/userfaultfd.h b/include/uapi/linux/userfaultfd.h
index bafbeb1a26245..298fbd4e2d1d3 100644
--- a/include/uapi/linux/userfaultfd.h
+++ b/include/uapi/linux/userfaultfd.h
@@ -31,7 +31,8 @@
UFFD_FEATURE_MISSING_SHMEM | \
UFFD_FEATURE_SIGBUS | \
UFFD_FEATURE_THREAD_ID | \
- UFFD_FEATURE_MINOR_HUGETLBFS)
+ UFFD_FEATURE_MINOR_HUGETLBFS | \
+ UFFD_FEATURE_WP_HUGETLBFS_SHMEM)
#define UFFD_API_IOCTLS \
((__u64)1 << _UFFDIO_REGISTER | \
(__u64)1 << _UFFDIO_UNREGISTER | \
@@ -45,7 +46,8 @@
#define UFFD_API_RANGE_IOCTLS_BASIC \
((__u64)1 << _UFFDIO_WAKE | \
(__u64)1 << _UFFDIO_COPY | \
- (__u64)1 << _UFFDIO_CONTINUE)
+ (__u64)1 << _UFFDIO_CONTINUE | \
+ (__u64)1 << _UFFDIO_WRITEPROTECT)
/*
* Valid ioctl command number range with this API is from 0x00 to
@@ -196,6 +198,7 @@ struct uffdio_api {
#define UFFD_FEATURE_SIGBUS (1<<7)
#define UFFD_FEATURE_THREAD_ID (1<<8)
#define UFFD_FEATURE_MINOR_HUGETLBFS (1<<9)
+#define UFFD_FEATURE_WP_HUGETLBFS_SHMEM (1<<10)
__u64 features;
__u64 ioctls;
diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
index 2cd6ad5c3d8f8..3930e56aaefd8 100644
--- a/mm/userfaultfd.c
+++ b/mm/userfaultfd.c
@@ -445,7 +445,6 @@ static __always_inline ssize_t mfill_atomic_pte(struct mm_struct *dst_mm,
err = mfill_zeropage_pte(dst_mm, dst_pmd,
dst_vma, dst_addr);
} else {
- VM_WARN_ON_ONCE(wp_copy);
if (!zeropage)
err = shmem_mcopy_atomic_pte(dst_mm, dst_pmd,
dst_vma, dst_addr,
@@ -682,15 +681,12 @@ int mwriteprotect_range(struct mm_struct *dst_mm, unsigned long start,
err = -ENOENT;
dst_vma = find_dst_vma(dst_mm, start, len);
- /*
- * Make sure the vma is not shared, that the dst range is
- * both valid and fully within a single existing vma.
- */
- if (!dst_vma || (dst_vma->vm_flags & VM_SHARED))
+
+ if (!dst_vma)
goto out_unlock;
if (!userfaultfd_wp(dst_vma))
goto out_unlock;
- if (!vma_is_anonymous(dst_vma))
+ if (!vma_can_userfault(dst_vma, dst_vma->vm_flags))
goto out_unlock;
if (is_vm_hugetlb_page(dst_vma)) {
--
2.26.2
next prev parent reply other threads:[~2021-04-27 16:24 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-27 16:12 [PATCH v2 00/24] userfaultfd-wp: Support shmem and hugetlbfs Peter Xu
2021-04-27 16:12 ` [PATCH v2 01/24] shmem/userfaultfd: Take care of UFFDIO_COPY_MODE_WP Peter Xu
2021-04-27 16:12 ` [PATCH v2 02/24] mm: Clear vmf->pte after pte_unmap_same() returns Peter Xu
2021-04-27 16:12 ` [PATCH v2 03/24] mm/userfaultfd: Introduce special pte for unmapped file-backed mem Peter Xu
2021-04-27 16:12 ` [PATCH v2 04/24] mm/swap: Introduce the idea of special swap ptes Peter Xu
2021-04-27 16:12 ` [PATCH v2 05/24] shmem/userfaultfd: Handle uffd-wp special pte in page fault handler Peter Xu
2021-04-27 18:54 ` Peter Xu
2021-04-27 16:12 ` [PATCH v2 06/24] mm: Drop first_index/last_index in zap_details Peter Xu
2021-04-27 16:13 ` [PATCH v2 07/24] mm: Introduce zap_details.zap_flags Peter Xu
2021-04-27 16:13 ` [PATCH v2 08/24] mm: Introduce ZAP_FLAG_SKIP_SWAP Peter Xu
2021-04-27 16:13 ` [PATCH v2 09/24] mm: Pass zap_flags into unmap_mapping_pages() Peter Xu
2021-04-27 16:13 ` [PATCH v2 10/24] shmem/userfaultfd: Persist uffd-wp bit across zapping for file-backed Peter Xu
2021-04-27 16:13 ` [PATCH v2 11/24] shmem/userfaultfd: Allow wr-protect none pte for file-backed mem Peter Xu
2021-04-27 16:13 ` [PATCH v2 12/24] shmem/userfaultfd: Allows file-back mem to be uffd wr-protected on thps Peter Xu
2021-04-27 16:13 ` [PATCH v2 13/24] shmem/userfaultfd: Handle the left-overed special swap ptes Peter Xu
2021-04-27 16:13 ` [PATCH v2 14/24] shmem/userfaultfd: Pass over uffd-wp special swap pte when fork() Peter Xu
2021-04-27 16:13 ` [PATCH v2 15/24] mm/hugetlb: Drop __unmap_hugepage_range definition from hugetlb.h Peter Xu
2021-04-27 16:13 ` [PATCH v2 16/24] hugetlb/userfaultfd: Hook page faults for uffd write protection Peter Xu
2021-04-28 0:07 ` Peter Xu
2021-04-27 16:13 ` [PATCH v2 17/24] hugetlb/userfaultfd: Take care of UFFDIO_COPY_MODE_WP Peter Xu
2021-04-27 16:13 ` [PATCH v2 18/24] hugetlb/userfaultfd: Handle UFFDIO_WRITEPROTECT Peter Xu
2021-04-27 16:13 ` [PATCH v2 19/24] mm/hugetlb: Introduce huge version of special swap pte helpers Peter Xu
2021-04-27 16:13 ` [PATCH v2 20/24] hugetlb/userfaultfd: Handle uffd-wp special pte in hugetlb pf handler Peter Xu
2021-04-27 16:13 ` [PATCH v2 21/24] hugetlb/userfaultfd: Allow wr-protect none ptes Peter Xu
2021-04-27 16:13 ` [PATCH v2 22/24] hugetlb/userfaultfd: Only drop uffd-wp special pte if required Peter Xu
2021-04-27 16:13 ` Peter Xu [this message]
2021-04-27 16:13 ` [PATCH v2 24/24] userfaultfd/selftests: Enable uffd-wp for shmem/hugetlbfs Peter Xu
2021-05-12 19:00 ` [PATCH v2 00/24] userfaultfd-wp: Support shmem and hugetlbfs Peter Xu
2021-05-14 7:07 ` Hugh Dickins
2021-05-14 13:18 ` Peter Xu
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