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[Qemu-devel] [PATCH v5 21/45] Add Linux userfaultfd header


From: Dr. David Alan Gilbert (git)
Subject: [Qemu-devel] [PATCH v5 21/45] Add Linux userfaultfd header
Date: Wed, 25 Feb 2015 16:51:44 +0000

From: "Dr. David Alan Gilbert" <address@hidden>

TODO: Update when kernel interface settles
      Update update-linux-headers.sh

Signed-off-by: Dr. David Alan Gilbert <address@hidden>
---
 linux-headers/linux/userfaultfd.h | 150 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 150 insertions(+)
 create mode 100644 linux-headers/linux/userfaultfd.h

diff --git a/linux-headers/linux/userfaultfd.h 
b/linux-headers/linux/userfaultfd.h
new file mode 100644
index 0000000..db6e99a
--- /dev/null
+++ b/linux-headers/linux/userfaultfd.h
@@ -0,0 +1,150 @@
+/*
+ *  include/linux/userfaultfd.h
+ *
+ *  Copyright (C) 2007  Davide Libenzi <address@hidden>
+ *  Copyright (C) 2015  Red Hat, Inc.
+ *
+ */
+
+#ifndef _LINUX_USERFAULTFD_H
+#define _LINUX_USERFAULTFD_H
+
+#define UFFD_API ((__u64)0xAA)
+/* FIXME: add "|UFFD_BIT_WP" to UFFD_API_BITS after implementing it */
+#define UFFD_API_BITS (UFFD_BIT_WRITE)
+#define UFFD_API_IOCTLS                                \
+       ((__u64)1 << _UFFDIO_REGISTER |         \
+        (__u64)1 << _UFFDIO_UNREGISTER |       \
+        (__u64)1 << _UFFDIO_API)
+#define UFFD_API_RANGE_IOCTLS                  \
+       ((__u64)1 << _UFFDIO_WAKE |             \
+        (__u64)1 << _UFFDIO_COPY |             \
+        (__u64)1 << _UFFDIO_ZEROPAGE |         \
+        (__u64)1 << _UFFDIO_REMAP)
+
+/*
+ * Valid ioctl command number range with this API is from 0x00 to
+ * 0x3F.  UFFDIO_API is the fixed number, everything else can be
+ * changed by implementing a different UFFD_API. If sticking to the
+ * same UFFD_API more ioctl can be added and userland will be aware of
+ * which ioctl the running kernel implements through the ioctl command
+ * bitmask written by the UFFDIO_API.
+ */
+#define _UFFDIO_REGISTER               (0x00)
+#define _UFFDIO_UNREGISTER             (0x01)
+#define _UFFDIO_WAKE                   (0x02)
+#define _UFFDIO_COPY                   (0x03)
+#define _UFFDIO_ZEROPAGE               (0x04)
+#define _UFFDIO_REMAP                  (0x05)
+#define _UFFDIO_API                    (0x3F)
+
+/* userfaultfd ioctl ids */
+#define UFFDIO 0xAA
+#define UFFDIO_API             _IOWR(UFFDIO, _UFFDIO_API,      \
+                                     struct uffdio_api)
+#define UFFDIO_REGISTER                _IOWR(UFFDIO, _UFFDIO_REGISTER, \
+                                     struct uffdio_register)
+#define UFFDIO_UNREGISTER      _IOR(UFFDIO, _UFFDIO_UNREGISTER,        \
+                                    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)
+#define UFFDIO_REMAP           _IOWR(UFFDIO, _UFFDIO_REMAP,    \
+                                     struct uffdio_remap)
+
+/*
+ * Valid bits below PAGE_SHIFT in the userfault address read through
+ * the read() syscall.
+ */
+#define UFFD_BIT_WRITE (1<<0)  /* this was a write fault, MISSING or WP */
+#define UFFD_BIT_WP    (1<<1)  /* handle_userfault() reason VM_UFFD_WP */
+#define UFFD_BITS      2       /* two above bits used for UFFD_BIT_* mask */
+
+struct uffdio_api {
+       /* userland asks for an API number */
+       __u64 api;
+
+       /* kernel answers below with the available features for the API */
+       __u64 bits;
+       __u64 ioctls;
+};
+
+struct uffdio_range {
+       __u64 start;
+       __u64 len;
+};
+
+struct uffdio_register {
+       struct uffdio_range range;
+#define UFFDIO_REGISTER_MODE_MISSING   ((__u64)1<<0)
+#define UFFDIO_REGISTER_MODE_WP                ((__u64)1<<1)
+       __u64 mode;
+
+       /*
+        * kernel answers which ioctl commands are available for the
+        * range, keep at the end as the last 8 bytes aren't read.
+        */
+       __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" and "wake" are written by the ioctl and must be at
+        * the end: the copy_from_user will not read the last 16
+        * bytes.
+        */
+       __s64 copy;
+       __s64 wake;
+};
+
+struct uffdio_zeropage {
+       struct uffdio_range range;
+#define UFFDIO_ZEROPAGE_MODE_DONTWAKE          ((__u64)1<<0)
+       __u64 mode;
+
+       /*
+        * "zeropage" and "wake" are written by the ioctl and must be
+        * at the end: the copy_from_user will not read the last 16
+        * bytes.
+        */
+       __s64 zeropage;
+       __s64 wake;
+};
+
+struct uffdio_remap {
+       __u64 dst;
+       __u64 src;
+       __u64 len;
+       /*
+        * Especially if used to atomically remove memory from the
+        * address space the wake on the dst range is not needed.
+        */
+#define UFFDIO_REMAP_MODE_DONTWAKE             ((__u64)1<<0)
+#define UFFDIO_REMAP_MODE_ALLOW_SRC_HOLES      ((__u64)1<<1)
+       __u64 mode;
+
+       /*
+        * "remap" and "wake" are written by the ioctl and must be at
+        * the end: the copy_from_user will not read the last 16
+        * bytes.
+        */
+       __s64 remap;
+       __s64 wake;
+};
+
+#endif /* _LINUX_USERFAULTFD_H */
-- 
2.1.0




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