diff options
Diffstat (limited to 'util/mmap-alloc.c')
| -rw-r--r-- | util/mmap-alloc.c | 41 |
1 files changed, 40 insertions, 1 deletions
diff --git a/util/mmap-alloc.c b/util/mmap-alloc.c index 9713f4b960..f7f177d0ea 100644 --- a/util/mmap-alloc.c +++ b/util/mmap-alloc.c @@ -10,6 +10,13 @@ * later. See the COPYING file in the top-level directory. */ +#ifdef CONFIG_LINUX +#include <linux/mman.h> +#else /* !CONFIG_LINUX */ +#define MAP_SYNC 0x0 +#define MAP_SHARED_VALIDATE 0x0 +#endif /* CONFIG_LINUX */ + #include "qemu/osdep.h" #include "qemu/mmap-alloc.h" #include "qemu/host-utils.h" @@ -82,6 +89,7 @@ void *qemu_ram_mmap(int fd, bool is_pmem) { int flags; + int map_sync_flags = 0; int guardfd; size_t offset; size_t pagesize; @@ -132,9 +140,40 @@ void *qemu_ram_mmap(int fd, flags = MAP_FIXED; flags |= fd == -1 ? MAP_ANONYMOUS : 0; flags |= shared ? MAP_SHARED : MAP_PRIVATE; + if (shared && is_pmem) { + map_sync_flags = MAP_SYNC | MAP_SHARED_VALIDATE; + } + offset = QEMU_ALIGN_UP((uintptr_t)guardptr, align) - (uintptr_t)guardptr; - ptr = mmap(guardptr + offset, size, PROT_READ | PROT_WRITE, flags, fd, 0); + ptr = mmap(guardptr + offset, size, PROT_READ | PROT_WRITE, + flags | map_sync_flags, fd, 0); + + if (ptr == MAP_FAILED && map_sync_flags) { + if (errno == ENOTSUP) { + char *proc_link, *file_name; + int len; + proc_link = g_strdup_printf("/proc/self/fd/%d", fd); + file_name = g_malloc0(PATH_MAX); + len = readlink(proc_link, file_name, PATH_MAX - 1); + if (len < 0) { + len = 0; + } + file_name[len] = '\0'; + fprintf(stderr, "Warning: requesting persistence across crashes " + "for backend file %s failed. Proceeding without " + "persistence, data might become corrupted in case of host " + "crash.\n", file_name); + g_free(proc_link); + g_free(file_name); + } + /* + * if map failed with MAP_SHARED_VALIDATE | MAP_SYNC, + * we will remove these flags to handle compatibility. + */ + ptr = mmap(guardptr + offset, size, PROT_READ | PROT_WRITE, + flags, fd, 0); + } if (ptr == MAP_FAILED) { munmap(guardptr, total); |