Currently, file_ram_alloc() only works on directory - it creates a file under @path and do mmap on it
This patch tries to allow it to work on file directly, if @path is a directory it works as before, otherwise it treats @path as the target file then directly allocate memory from it Signed-off-by: Xiao Guangrong <guangrong.x...@linux.intel.com> --- exec.c | 82 ++++++++++++++++++++++++++++++++++++++++++------------------------ 1 file changed, 52 insertions(+), 30 deletions(-) diff --git a/exec.c b/exec.c index 70cb0ef..c8c7e12 100644 --- a/exec.c +++ b/exec.c @@ -1154,14 +1154,60 @@ void qemu_mutex_unlock_ramlist(void) } #ifdef __linux__ +static bool path_is_dir(const char *path) +{ + struct stat fs; + + return stat(path, &fs) == 0 && S_ISDIR(fs.st_mode); +} + +static int open_file_path(RAMBlock *block, const char *path, size_t size) +{ + char *filename; + char *sanitized_name; + char *c; + int fd; + + if (!path_is_dir(path)) { + int flags = (block->flags & RAM_SHARED) ? O_RDWR : O_RDONLY; + + flags |= O_EXCL; + return open(path, flags); + } + + /* Make name safe to use with mkstemp by replacing '/' with '_'. */ + sanitized_name = g_strdup(memory_region_name(block->mr)); + for (c = sanitized_name; *c != '\0'; c++) { + if (*c == '/') { + *c = '_'; + } + } + filename = g_strdup_printf("%s/qemu_back_mem.%s.XXXXXX", path, + sanitized_name); + g_free(sanitized_name); + fd = mkstemp(filename); + if (fd >= 0) { + unlink(filename); + /* + * ftruncate is not supported by hugetlbfs in older + * hosts, so don't bother bailing out on errors. + * If anything goes wrong with it under other filesystems, + * mmap will fail. + */ + if (ftruncate(fd, size)) { + perror("ftruncate"); + } + } + g_free(filename); + + return fd; +} + static void *file_ram_alloc(RAMBlock *block, ram_addr_t memory, const char *path, Error **errp) { - char *filename; - char *sanitized_name; - char *c; void *ptr; void *area = NULL; int fd; @@ -1189,39 +1235,15 @@ static void *file_ram_alloc(RAMBlock *block, goto error; } - /* Make name safe to use with mkstemp by replacing '/' with '_'. */ - sanitized_name = g_strdup(memory_region_name(block->mr)); - for (c = sanitized_name; *c != '\0'; c++) { - if (*c == '/') - *c = '_'; - } - - filename = g_strdup_printf("%s/qemu_back_mem.%s.XXXXXX", path, - sanitized_name); - g_free(sanitized_name); + memory = ROUND_UP(memory, pagesize); + total = memory + pagesize; - fd = mkstemp(filename); + fd = open_file_path(block, path, memory); if (fd < 0) { error_setg_errno(errp, errno, "unable to create backing store for path %s", path); - g_free(filename); goto error; } - unlink(filename); - g_free(filename); - - memory = ROUND_UP(memory, pagesize); - total = memory + pagesize; - - /* - * ftruncate is not supported by hugetlbfs in older - * hosts, so don't bother bailing out on errors. - * If anything goes wrong with it under other filesystems, - * mmap will fail. - */ - if (ftruncate(fd, memory)) { - perror("ftruncate"); - } ptr = mmap(0, total, PROT_NONE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); -- 1.8.3.1 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html