include/qemu/mmap-alloc.h

   1 #ifndef QEMU_MMAP_ALLOC_H
   2 #define QEMU_MMAP_ALLOC_H
   3
   4 typedef enum {
   5     QEMU_FS_TYPE_UNKNOWN = 0,
   6     QEMU_FS_TYPE_TMPFS,
   7     QEMU_FS_TYPE_HUGETLBFS,
   8     QEMU_FS_TYPE_NUM,
   9 } QemuFsType;
  10
  11 size_t qemu_fd_getpagesize(int fd);
  12 QemuFsType qemu_fd_getfs(int fd);
  13
  14 /**
  15  * qemu_ram_mmap: mmap anonymous memory, the specified file or device.
  16  *
  17  * mmap() abstraction to map guest RAM, simplifying flag handling, taking
  18  * care of alignment requirements and installing guard pages.
  19  *
  20  * Parameters:
  21  *  @fd: the file or the device to mmap
  22  *  @size: the number of bytes to be mmaped
  23  *  @align: if not zero, specify the alignment of the starting mapping address;
  24  *          otherwise, the alignment in use will be determined by QEMU.
  25  *  @qemu_map_flags: QEMU_MAP_* flags
  26  *  @map_offset: map starts at offset of map_offset from the start of fd
  27  *
  28  * Internally, MAP_PRIVATE, MAP_ANONYMOUS and MAP_SHARED_VALIDATE are set
  29  * implicitly based on other parameters.
  30  *
  31  * Return:
  32  *  On success, return a pointer to the mapped area.
  33  *  On failure, return MAP_FAILED.
  34  */
  35 void *qemu_ram_mmap(int fd,
  36                     size_t size,
  37                     size_t align,
  38                     uint32_t qemu_map_flags,
  39                     off_t map_offset);
  40
  41 void qemu_ram_munmap(int fd, void *ptr, size_t size);
  42
  43 /*
  44  * Abstraction of PROT_ and MAP_ flags as passed to mmap(), for example,
  45  * consumed by qemu_ram_mmap().
  46  */
  47
  48 /* Map PROT_READ instead of PROT_READ | PROT_WRITE. */
  49 #define QEMU_MAP_READONLY   (1 << 0)
  50
  51 /* Use MAP_SHARED instead of MAP_PRIVATE. */
  52 #define QEMU_MAP_SHARED     (1 << 1)
  53
  54 /*
  55  * Use MAP_SYNC | MAP_SHARED_VALIDATE if supported. Ignored without
  56  * QEMU_MAP_SHARED. If mapping fails, warn and fallback to !QEMU_MAP_SYNC.
  57  */
  58 #define QEMU_MAP_SYNC       (1 << 2)
  59
  60 /*
  61  * Use MAP_NORESERVE to skip reservation of swap space (or huge pages if
  62  * applicable). Bail out if not supported/effective.
  63  */
  64 #define QEMU_MAP_NORESERVE  (1 << 3)
  65
  66 #endif