include/qemu/mmap-alloc.h

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