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[v6,8/8] memfd_create.2: Describe MFD_INACCESSIBLE flag

Message ID 20220519153713.819591-9-chao.p.peng@linux.intel.com (mailing list archive)
State New, archived
Headers show
Series KVM: mm: fd-based approach for supporting KVM guest private memory | expand

Commit Message

Chao Peng May 19, 2022, 3:37 p.m. UTC 
Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com>
---
 man2/memfd_create.2 | 13 +++++++++++++
 1 file changed, 13 insertions(+)
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Patch

diff --git a/man2/memfd_create.2 b/man2/memfd_create.2
index 89e9c4136..2698222ae 100644
--- a/man2/memfd_create.2
+++ b/man2/memfd_create.2
@@ -101,6 +101,19 @@  meaning that no other seals can be set on the file.
 .\" FIXME Why is the MFD_ALLOW_SEALING behavior not simply the default?
 .\" Is it worth adding some text explaining this?
 .TP
+.BR MFD_INACCESSIBLE
+Disallow userspace access through ordinary MMU accesses via
+.BR read (2),
+.BR write (2)
+and
+.BR mmap (2).
+The file size cannot be changed once initialized.
+This flag cannot coexist with
+.B MFD_ALLOW_SEALING
+and when this flag is set, the initial set of seals will be
+.B F_SEAL_SEAL,
+meaning that no other seals can be set on the file.
+.TP
 .BR MFD_HUGETLB " (since Linux 4.14)"
 .\" commit 749df87bd7bee5a79cef073f5d032ddb2b211de8
 The anonymous file will be created in the hugetlbfs filesystem using