userfaultfd: UFFDIO_COPY|UFFDIO_ZEROPAGE uAPI

This implements the uABI of UFFDIO_COPY and UFFDIO_ZEROPAGE.

include/uapi/linux/userfaultfd.h

@@ -21,7 +21,9 @@
 	 (__u64)1 << _UFFDIO_UNREGISTER |	\
 	 (__u64)1 << _UFFDIO_API)
 #define UFFD_API_RANGE_IOCTLS			\
-	((__u64)1 << _UFFDIO_WAKE)
+	((__u64)1 << _UFFDIO_WAKE |		\
+	 (__u64)1 << _UFFDIO_COPY |		\
+	 (__u64)1 << _UFFDIO_ZEROPAGE)
 
 /*
  * Valid ioctl command number range with this API is from 0x00 to
@@ -34,6 +36,8 @@
 #define _UFFDIO_REGISTER		(0x00)
 #define _UFFDIO_UNREGISTER		(0x01)
 #define _UFFDIO_WAKE			(0x02)
+#define _UFFDIO_COPY			(0x03)
+#define _UFFDIO_ZEROPAGE		(0x04)
 #define _UFFDIO_API			(0x3F)
 
 /* userfaultfd ioctl ids */
@@ -46,6 +50,10 @@
 				     struct uffdio_range)
 #define UFFDIO_WAKE		_IOR(UFFDIO, _UFFDIO_WAKE,	\
 				     struct uffdio_range)
+#define UFFDIO_COPY		_IOWR(UFFDIO, _UFFDIO_COPY,	\
+				      struct uffdio_copy)
+#define UFFDIO_ZEROPAGE		_IOWR(UFFDIO, _UFFDIO_ZEROPAGE,	\
+				      struct uffdio_zeropage)
 
 /* read() structure */
 struct uffd_msg {
@@ -118,4 +126,36 @@ struct uffdio_register {
 	__u64 ioctls;
 };
 
+struct uffdio_copy {
+	__u64 dst;
+	__u64 src;
+	__u64 len;
+	/*
+	 * There will be a wrprotection flag later that allows to map
+	 * pages wrprotected on the fly. And such a flag will be
+	 * available if the wrprotection ioctl are implemented for the
+	 * range according to the uffdio_register.ioctls.
+	 */
+#define UFFDIO_COPY_MODE_DONTWAKE		((__u64)1<<0)
+	__u64 mode;
+
+	/*
+	 * "copy" is written by the ioctl and must be at the end: the
+	 * copy_from_user will not read the last 8 bytes.
+	 */
+	__s64 copy;
+};
+
+struct uffdio_zeropage {
+	struct uffdio_range range;
+#define UFFDIO_ZEROPAGE_MODE_DONTWAKE		((__u64)1<<0)
+	__u64 mode;
+
+	/*
+	 * "zeropage" is written by the ioctl and must be at the end:
+	 * the copy_from_user will not read the last 8 bytes.
+	 */
+	__s64 zeropage;
+};
+
 #endif /* _LINUX_USERFAULTFD_H */