Let's pass flags instead of bools to prepare for passing other flags and
update the documentation of qemu_ram_mmap(). Introduce new QEMU_MAP_
flags that abstract the mmap() PROT_ and MAP_ flag handling and simplify
it.
We expose only flags that are currently supported by qemu_ram_mmap().
Maybe, we'll see qemu_mmap() in the future as well that can implement these
flags.
Note: We don't use MAP_ flags as some flags (e.g., MAP_SYNC) are only
defined for some systems and we want to always be able to identify
these flags reliably inside qemu_ram_mmap() -- for example, to properly
warn when some future flags are not available or effective on a system.
Also, this way we can simplify PROT_ handling as well.
Signed-off-by: David Hildenbrand <david@redhat.com>
---
include/qemu/mmap-alloc.h | 16 +++++++++-------
include/qemu/osdep.h | 18 ++++++++++++++++++
softmmu/physmem.c | 8 +++++---
util/mmap-alloc.c | 15 ++++++++-------
util/oslib-posix.c | 3 ++-
5 files changed, 42 insertions(+), 18 deletions(-)
diff --git a/include/qemu/mmap-alloc.h b/include/qemu/mmap-alloc.h
index 456ff87df1..a60a2085b3 100644
--- a/include/qemu/mmap-alloc.h
+++ b/include/qemu/mmap-alloc.h
@@ -7,18 +7,22 @@ size_t qemu_fd_getpagesize(int fd);
size_t qemu_mempath_getpagesize(const char *mem_path);
/**
- * qemu_ram_mmap: mmap the specified file or device.
+ * qemu_ram_mmap: mmap anonymous memory, the specified file or device.
+ *
+ * mmap() abstraction to map guest RAM, simplifying flag handling, taking
+ * care of alignment requirements and installing guard pages.
*
* Parameters:
* @fd: the file or the device to mmap
* @size: the number of bytes to be mmaped
* @align: if not zero, specify the alignment of the starting mapping
address;
* otherwise, the alignment in use will be determined by QEMU.
- * @readonly: true for a read-only mapping, false for read/write.
- * @shared: map has RAM_SHARED flag.
- * @is_pmem: map has RAM_PMEM flag.
+ * @qemu_map_flags: QEMU_MAP_* flags
* @map_offset: map starts at offset of map_offset from the start of fd
*
+ * Internally, MAP PRIVATE, MAP_ANONYMOUS and MAP_SHARED_VALIDATE are set