@@ -11,13 +11,18 @@
#include <linux/types.h>
-#define UFFD_API ((__u64)0xAA)
/*
- * After implementing the respective features it will become:
- * #define UFFD_API_FEATURES (UFFD_FEATURE_PAGEFAULT_FLAG_WP | \
- * UFFD_FEATURE_EVENT_FORK)
+ * If the UFFDIO_API is upgraded someday, the UFFDIO_UNREGISTER and
+ * UFFDIO_WAKE ioctls should be defined as _IOW and not as _IOR. In
+ * userfaultfd.h we assumed the kernel was reading (instead _IOC_READ
+ * means the userland is reading).
*/
-#define UFFD_API_FEATURES (0)
+#define UFFD_API ((__u64)0xAA)
+#define UFFD_API_FEATURES (UFFD_FEATURE_EVENT_FORK | \
+ UFFD_FEATURE_EVENT_REMAP | \
+ UFFD_FEATURE_EVENT_MADVDONTNEED | \
+ UFFD_FEATURE_MISSING_HUGETLBFS | \
+ UFFD_FEATURE_MISSING_SHMEM)
#define UFFD_API_IOCTLS \
((__u64)1 << _UFFDIO_REGISTER | \
(__u64)1 << _UFFDIO_UNREGISTER | \
@@ -26,6 +31,9 @@
((__u64)1 << _UFFDIO_WAKE | \
(__u64)1 << _UFFDIO_COPY | \
(__u64)1 << _UFFDIO_ZEROPAGE)
+#define UFFD_API_RANGE_IOCTLS_BASIC \
+ ((__u64)1 << _UFFDIO_WAKE | \
+ (__u64)1 << _UFFDIO_COPY)
/*
* Valid ioctl command number range with this API is from 0x00 to
@@ -72,6 +80,21 @@ struct uffd_msg {
} pagefault;
struct {
+ __u32 ufd;
+ } fork;
+
+ struct {
+ __u64 from;
+ __u64 to;
+ __u64 len;
+ } remap;
+
+ struct {
+ __u64 start;
+ __u64 end;
+ } madv_dn;
+
+ struct {
/* unused reserved fields */
__u64 reserved1;
__u64 reserved2;
@@ -84,9 +107,9 @@ struct uffd_msg {
* Start at 0x12 and not at 0 to be more strict against bugs.
*/
#define UFFD_EVENT_PAGEFAULT 0x12
-#if 0 /* not available yet */
#define UFFD_EVENT_FORK 0x13
-#endif
+#define UFFD_EVENT_REMAP 0x14
+#define UFFD_EVENT_MADVDONTNEED 0x15
/* flags for UFFD_EVENT_PAGEFAULT */
#define UFFD_PAGEFAULT_FLAG_WRITE (1<<0) /* If this was a write fault */
@@ -104,11 +127,37 @@ 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).
*/
-#if 0 /* not available yet */
#define UFFD_FEATURE_PAGEFAULT_FLAG_WP (1<<0)
#define UFFD_FEATURE_EVENT_FORK (1<<1)
-#endif
+#define UFFD_FEATURE_EVENT_REMAP (1<<2)
+#define UFFD_FEATURE_EVENT_MADVDONTNEED (1<<3)
+#define UFFD_FEATURE_MISSING_HUGETLBFS (1<<4)
+#define UFFD_FEATURE_MISSING_SHMEM (1<<5)
__u64 features;
__u64 ioctls;