diff options
Diffstat (limited to 'util/mmap-alloc.c')
| -rw-r--r-- | util/mmap-alloc.c | 17 |
1 files changed, 8 insertions, 9 deletions
diff --git a/util/mmap-alloc.c b/util/mmap-alloc.c index 5a85aa3c89..2f55f5e94f 100644 --- a/util/mmap-alloc.c +++ b/util/mmap-alloc.c @@ -12,6 +12,7 @@ #include "qemu/osdep.h" #include "qemu/mmap-alloc.h" +#include "qemu/host-utils.h" #define HUGETLBFS_MAGIC 0x958458f6 @@ -61,18 +62,18 @@ void *qemu_ram_mmap(int fd, size_t size, size_t align, bool shared) #else void *ptr = mmap(0, total, PROT_NONE, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); #endif - size_t offset = QEMU_ALIGN_UP((uintptr_t)ptr, align) - (uintptr_t)ptr; + size_t offset; void *ptr1; if (ptr == MAP_FAILED) { return MAP_FAILED; } - /* Make sure align is a power of 2 */ - assert(!(align & (align - 1))); + assert(is_power_of_2(align)); /* Always align to host page size */ assert(align >= getpagesize()); + offset = QEMU_ALIGN_UP((uintptr_t)ptr, align) - (uintptr_t)ptr; ptr1 = mmap(ptr + offset, size, PROT_READ | PROT_WRITE, MAP_FIXED | (fd == -1 ? MAP_ANONYMOUS : 0) | @@ -83,22 +84,20 @@ void *qemu_ram_mmap(int fd, size_t size, size_t align, bool shared) return MAP_FAILED; } - ptr += offset; - total -= offset; - if (offset > 0) { - munmap(ptr - offset, offset); + munmap(ptr, offset); } /* * Leave a single PROT_NONE page allocated after the RAM block, to serve as * a guard page guarding against potential buffer overflows. */ + total -= offset; if (total > size + getpagesize()) { - munmap(ptr + size + getpagesize(), total - size - getpagesize()); + munmap(ptr1 + size + getpagesize(), total - size - getpagesize()); } - return ptr; + return ptr1; } void qemu_ram_munmap(void *ptr, size_t size) |