[CRIU] [RFC PATCH v2 11/23] Update criu/include/linux/userfaultfd.h

[Mike Rapoport]

This is the version from linux-next at the moment.

Signed-off-by: Mike Rapoport <rppt at linux.vnet.ibm.com>
---
 criu/cr-check.c                  |  2 +-
 criu/include/linux/userfaultfd.h | 60 +++++++++++++++++++++++++++-------------
 2 files changed, 42 insertions(+), 20 deletions(-)

diff --git a/criu/cr-check.c b/criu/cr-check.c
index 431a998..77e91f1 100644
--- a/criu/cr-check.c
+++ b/criu/cr-check.c
@@ -1031,7 +1031,7 @@ static int check_uffd(void)
 {
 	unsigned long features = UFFD_FEATURE_EVENT_FORK |
 		UFFD_FEATURE_EVENT_REMAP |
-		UFFD_FEATURE_EVENT_MADVDONTNEED;
+		UFFD_FEATURE_EVENT_REMOVE;
 
 	if (kerndat_uffd(true))
 		return -1;
diff --git a/criu/include/linux/userfaultfd.h b/criu/include/linux/userfaultfd.h
index a9c3389..c055947 100644
--- a/criu/include/linux/userfaultfd.h
+++ b/criu/include/linux/userfaultfd.h
@@ -18,10 +18,13 @@
  * means the userland is reading).
  */
 #define UFFD_API ((__u64)0xAA)
-#define UFFD_API_FEATURES (UFFD_FEATURE_PAGEFAULT_FLAG_WP | \
-			   UFFD_FEATURE_EVENT_FORK |	    \
-			   UFFD_FEATURE_EVENT_REMAP |	    \
-			   UFFD_FEATURE_EVENT_MADVDONTNEED)
+#define UFFD_API_FEATURES (UFFD_FEATURE_EVENT_EXIT |		\
+			   UFFD_FEATURE_EVENT_FORK |		\
+			   UFFD_FEATURE_EVENT_REMAP |		\
+			   UFFD_FEATURE_EVENT_REMOVE |	\
+			   UFFD_FEATURE_EVENT_UNMAP |		\
+			   UFFD_FEATURE_MISSING_HUGETLBFS |	\
+			   UFFD_FEATURE_MISSING_SHMEM)
 #define UFFD_API_IOCTLS				\
 	((__u64)1 << _UFFDIO_REGISTER |		\
 	 (__u64)1 << _UFFDIO_UNREGISTER |	\
@@ -29,8 +32,7 @@
 #define UFFD_API_RANGE_IOCTLS			\
 	((__u64)1 << _UFFDIO_WAKE |		\
 	 (__u64)1 << _UFFDIO_COPY |		\
-	 (__u64)1 << _UFFDIO_ZEROPAGE |		\
-	 (__u64)1 << _UFFDIO_WRITEPROTECT)
+	 (__u64)1 << _UFFDIO_ZEROPAGE)
 #define UFFD_API_RANGE_IOCTLS_BASIC		\
 	((__u64)1 << _UFFDIO_WAKE |		\
 	 (__u64)1 << _UFFDIO_COPY)
@@ -48,7 +50,6 @@
 #define _UFFDIO_WAKE			(0x02)
 #define _UFFDIO_COPY			(0x03)
 #define _UFFDIO_ZEROPAGE		(0x04)
-#define _UFFDIO_WRITEPROTECT		(0x05)
 #define _UFFDIO_API			(0x3F)
 
 /* userfaultfd ioctl ids */
@@ -65,8 +66,6 @@
 				      struct uffdio_copy)
 #define UFFDIO_ZEROPAGE		_IOWR(UFFDIO, _UFFDIO_ZEROPAGE,	\
 				      struct uffdio_zeropage)
-#define UFFDIO_WRITEPROTECT	_IOWR(UFFDIO, _UFFDIO_WRITEPROTECT, \
-				      struct uffdio_writeprotect)
 
 /* read() structure */
 struct uffd_msg {
@@ -95,7 +94,7 @@ struct uffd_msg {
 		struct {
 			__u64	start;
 			__u64	end;
-		} madv_dn;
+		} remove;
 
 		struct {
 			/* unused reserved fields */
@@ -112,7 +111,9 @@ struct uffd_msg {
 #define UFFD_EVENT_PAGEFAULT	0x12
 #define UFFD_EVENT_FORK		0x13
 #define UFFD_EVENT_REMAP	0x14
-#define UFFD_EVENT_MADVDONTNEED	0x15
+#define UFFD_EVENT_REMOVE	0x15
+#define UFFD_EVENT_UNMAP	0x16
+#define UFFD_EVENT_EXIT		0x17
 
 /* flags for UFFD_EVENT_PAGEFAULT */
 #define UFFD_PAGEFAULT_FLAG_WRITE	(1<<0)	/* If this was a write fault */
@@ -130,11 +131,39 @@ struct uffdio_api {
 	 * Note: UFFD_EVENT_PAGEFAULT and UFFD_PAGEFAULT_FLAG_WRITE
 	 * are to be considered implicitly always enabled in all kernels as
 	 * long as the uffdio_api.api requested matches UFFD_API.
+	 *
+	 * UFFD_FEATURE_MISSING_HUGETLBFS means an UFFDIO_REGISTER
+	 * with UFFDIO_REGISTER_MODE_MISSING mode will succeed on
+	 * hugetlbfs virtual memory ranges. Adding or not adding
+	 * UFFD_FEATURE_MISSING_HUGETLBFS to uffdio_api.features has
+	 * no real functional effect after UFFDIO_API returns, but
+	 * it's only useful for an initial feature set probe at
+	 * UFFDIO_API time. There are two ways to use it:
+	 *
+	 * 1) by adding UFFD_FEATURE_MISSING_HUGETLBFS to the
+	 *    uffdio_api.features before calling UFFDIO_API, an error
+	 *    will be returned by UFFDIO_API on a kernel without
+	 *    hugetlbfs missing support
+	 *
+	 * 2) the UFFD_FEATURE_MISSING_HUGETLBFS can not be added in
+	 *    uffdio_api.features and instead it will be set by the
+	 *    kernel in the uffdio_api.features if the kernel supports
+	 *    it, so userland can later check if the feature flag is
+	 *    present in uffdio_api.features after UFFDIO_API
+	 *    succeeded.
+	 *
+	 * UFFD_FEATURE_MISSING_SHMEM works the same as
+	 * UFFD_FEATURE_MISSING_HUGETLBFS, but it applies to shmem
+	 * (i.e. tmpfs and other shmem based APIs).
 	 */
 #define UFFD_FEATURE_PAGEFAULT_FLAG_WP		(1<<0)
 #define UFFD_FEATURE_EVENT_FORK			(1<<1)
 #define UFFD_FEATURE_EVENT_REMAP		(1<<2)
-#define UFFD_FEATURE_EVENT_MADVDONTNEED		(1<<3)
+#define UFFD_FEATURE_EVENT_REMOVE		(1<<3)
+#define UFFD_FEATURE_MISSING_HUGETLBFS		(1<<4)
+#define UFFD_FEATURE_MISSING_SHMEM		(1<<5)
+#define UFFD_FEATURE_EVENT_UNMAP		(1<<6)
+#define UFFD_FEATURE_EVENT_EXIT			(1<<7)
 	__u64 features;
 
 	__u64 ioctls;
@@ -190,11 +219,4 @@ struct uffdio_zeropage {
 	__s64 zeropage;
 };
 
-struct uffdio_writeprotect {
-	struct uffdio_range range;
-	/* !WP means undo writeprotect. DONTWAKE is valid only with !WP */
-#define UFFDIO_WRITEPROTECT_MODE_WP		((__u64)1<<0)
-#define UFFDIO_WRITEPROTECT_MODE_DONTWAKE	((__u64)1<<1)
-	__u64 mode;
-};
 #endif /* _LINUX_USERFAULTFD_H */
-- 
1.9.1