On Mon, 2 Nov 2015 17:13:11 +0800 Xiao Guangrong <guangrong.xiao@xxxxxxxxxxxxxxx> wrote: > 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 Paolo has just queued https://lists.gnu.org/archive/html/qemu-devel/2015-10/msg06513.html perhaps that's what you can reuse here. > > Signed-off-by: Xiao Guangrong <guangrong.xiao@xxxxxxxxxxxxxxx> > --- > exec.c | 80 ++++++++++++++++++++++++++++++++++++++++++------------------------ > 1 file changed, 51 insertions(+), 29 deletions(-) > > diff --git a/exec.c b/exec.c > index 9075f4d..db0fdaf 100644 > --- a/exec.c > +++ b/exec.c > @@ -1174,14 +1174,60 @@ 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_ram_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 *area; > int fd; > uint64_t pagesize; > @@ -1212,38 +1258,14 @@ 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); > > - fd = mkstemp(filename); > + fd = open_ram_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); > - > - /* > - * 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"); > - } > > area = qemu_ram_mmap(fd, memory, pagesize, block->flags & RAM_SHARED); > if (area == MAP_FAILED) { -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
