Signed-off-by: Zhang Yi <yi.z.zh...@linux.intel.com>
A set of RAM_SYNC_ON_OFF_AUTO{AUTO,ON,OFF} flags are added to
qemu_ram_mmap():
- If RAM_SYNC_ON_OFF_AUTO_ON is present, qemu_ram_mmap() will try to pass
MAP_SYNC to mmap(). It will then fail if the host OS or the backend
file do not support MAP_SYNC, or MAP_SYNC is conflict with other
flags.
- If RAM_SYNC_ON_OFF_AUTO_OFF is present, qemu_ram_mmap() will never pass
MAP_SYNC to mmap().
- If RAM_SYNC_ON_OFF_AUTO_AUTO is present, and
* if the host OS and the backend file support MAP_SYNC, and MAP_SYNC
is not conflict with other flags, qemu_ram_mmap() will work as if
RAM_SYNC_ON_OFF_AUTO_ON is present;
* otherwise, qemu_ram_mmap() will work as if RAM_SYNC_ON_OFF_AUTO_OFF is
present.
---
include/exec/memory.h | 9 ++++++++-
util/mmap-alloc.c | 13 +++++++++++--
2 files changed, 19 insertions(+), 3 deletions(-)
diff --git a/include/exec/memory.h b/include/exec/memory.h
index 33a4e2c..c74c467 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -127,7 +127,14 @@ typedef struct IOMMUNotifier IOMMUNotifier;
#define RAM_PMEM (1 << 5)
/* RAM can be mmap by a MAP_SYNC flag */
-#define RAM_SYNC (1 << 6)
+#define RAM_SYNC_SHIFT 6
+#define RAM_SYNC_SHIFT_AUTO 7
+
+#define RAM_SYNC_ON_OFF_AUTO_ON (1UL << RAM_SYNC_SHIFT)
+#define RAM_SYNC_ON_OFF_AUTO_OFF (0UL << RAM_SYNC_SHIFT)
+#define RAM_SYNC_ON_OFF_AUTO_AUTO (1UL << RAM_SYNC_SHIFT_AUTO)
+
+#define RAM_SYNC (RAM_SYNC_ON_OFF_AUTO_ON | RAM_SYNC_ON_OFF_AUTO_AUTO)
static inline void iommu_notifier_init(IOMMUNotifier *n, IOMMUNotify fn,
IOMMUNotifierFlag flags,
diff --git a/util/mmap-alloc.c b/util/mmap-alloc.c
index 89ae862..2f2fb43 100644
--- a/util/mmap-alloc.c
+++ b/util/mmap-alloc.c
@@ -111,6 +111,11 @@ void *qemu_ram_mmap(int fd, size_t size, size_t align,
uint32_t flags)
assert(is_power_of_2(align));
/* Always align to host page size */
assert(align >= getpagesize());
+ if ((flags & RAM_SYNC_ON_OFF_AUTO_ON) &&
+ (!shared || !MAP_SYNC_FLAGS || !is_pmem)) {
+ munmap(ptr, total);
+ return MAP_FAILED;
+ }
if ((flags & RAM_SYNC) && shared && is_pmem) {
mmap_xflags |= MAP_SYNC_FLAGS;
}
@@ -123,8 +128,12 @@ void *qemu_ram_mmap(int fd, size_t size, size_t align,
uint32_t flags)
(shared ? MAP_SHARED : MAP_PRIVATE) | mmap_xflags,
fd, 0);
if ((ptr1 == MAP_FAILED) && (mmap_xflags & MAP_SYNC_FLAGS)) {
- mmap_xflags &= ~MAP_SYNC_FLAGS;
- goto retry_mmap_fd;
+ if (flags & RAM_SYNC_ON_OFF_AUTO_AUTO) {
+ mmap_xflags &= ~MAP_SYNC_FLAGS;
+ goto retry_mmap_fd;
+ }
+ munmap(ptr, total);
+ return MAP_FAILED;
}
if (offset > 0) {
--
2.7.4
