Signed-off-by: Nikita Kalyazin <kalyazin@xxxxxxxxxx>
---
fs/userfaultfd.c | 3 ++-
include/uapi/linux/userfaultfd.h | 8 +++++++-
2 files changed, 9 insertions(+), 2 deletions(-)
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index 97c4d71115d8..32152bfa462a 100644
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -1954,7 +1954,8 @@ static int userfaultfd_api(struct userfaultfd_ctx *ctx,
uffdio_api.features = UFFD_API_FEATURES;
#ifndef CONFIG_HAVE_ARCH_USERFAULTFD_MINOR
uffdio_api.features &=
- ~(UFFD_FEATURE_MINOR_HUGETLBFS | UFFD_FEATURE_MINOR_SHMEM);
+ ~(UFFD_FEATURE_MINOR_HUGETLBFS | UFFD_FEATURE_MINOR_SHMEM |
+ UFFD_FEATURE_MINOR_GUEST_MEMFD);
#endif
#ifndef CONFIG_HAVE_ARCH_USERFAULTFD_WP
uffdio_api.features &= ~UFFD_FEATURE_PAGEFAULT_FLAG_WP;
diff --git a/include/uapi/linux/userfaultfd.h b/include/uapi/linux/userfaultfd.h
index 2841e4ea8f2c..ed688797eba7 100644
--- a/include/uapi/linux/userfaultfd.h
+++ b/include/uapi/linux/userfaultfd.h
@@ -42,7 +42,8 @@
UFFD_FEATURE_WP_UNPOPULATED | \
UFFD_FEATURE_POISON | \
UFFD_FEATURE_WP_ASYNC | \
- UFFD_FEATURE_MOVE)
+ UFFD_FEATURE_MOVE | \
+ UFFD_FEATURE_MINOR_GUEST_MEMFD)
#define UFFD_API_IOCTLS \
((__u64)1 << _UFFDIO_REGISTER | \
(__u64)1 << _UFFDIO_UNREGISTER | \
@@ -230,6 +231,10 @@ struct uffdio_api {
*
* UFFD_FEATURE_MOVE indicates that the kernel supports moving an
* existing page contents from userspace.
+ *
+ * UFFD_FEATURE_MINOR_GUEST_MEMFD indicates the same support as
+ * UFFD_FEATURE_MINOR_HUGETLBFS, but for guest_memfd-backed pages
+ * instead.
*/
#define UFFD_FEATURE_PAGEFAULT_FLAG_WP (1<<0)
#define UFFD_FEATURE_EVENT_FORK (1<<1)
@@ -248,6 +253,7 @@ struct uffdio_api {
#define UFFD_FEATURE_POISON (1<<14)
#define UFFD_FEATURE_WP_ASYNC (1<<15)
#define UFFD_FEATURE_MOVE (1<<16)
+#define UFFD_FEATURE_MINOR_GUEST_MEMFD (1<<17)
__u64 features;
__u64 ioctls;
--
2.47.1
