userfaultfd: non-cooperative: add event for memory unmaps

[karo-tx-linux.git] / include / uapi / linux / userfaultfd.h

diff --git a/include/uapi/linux/userfaultfd.h b/include/uapi/linux/userfaultfd.h
index 9057d7af3ae145ba711c837f4bcbe58e851f2320..3b059530dac95fa6e5dcf736e95a84fe80eb5f35 100644 (file)
--- a/include/uapi/linux/userfaultfd.h
+++ b/include/uapi/linux/userfaultfd.h
@@ -11,13 +11,19 @@
 
 #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_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 |       \
@@ -26,6 +32,9 @@
        ((__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
@@ -71,6 +80,21 @@ struct uffd_msg {
                        __u64   address;
                } pagefault;
 
+               struct {
+                       __u32   ufd;
+               } fork;
+
+               struct {
+                       __u64   from;
+                       __u64   to;
+                       __u64   len;
+               } remap;
+
+               struct {
+                       __u64   start;
+                       __u64   end;
+               } remove;
+
                struct {
                        /* unused reserved fields */
                        __u64   reserved1;
@@ -84,9 +108,10 @@ 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_REMOVE      0x15
+#define UFFD_EVENT_UNMAP       0x16
 
 /* flags for UFFD_EVENT_PAGEFAULT */
 #define UFFD_PAGEFAULT_FLAG_WRITE      (1<<0)  /* If this was a write fault */
@@ -104,11 +129,38 @@ 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_REMOVE              (1<<3)
+#define UFFD_FEATURE_MISSING_HUGETLBFS         (1<<4)
+#define UFFD_FEATURE_MISSING_SHMEM             (1<<5)
+#define UFFD_FEATURE_EVENT_UNMAP               (1<<6)
        __u64 features;
 
        __u64 ioctls;