diff --git a/usr.sbin/bhyve/qemu_fwcfg.c b/usr.sbin/bhyve/qemu_fwcfg.c
--- a/usr.sbin/bhyve/qemu_fwcfg.c
+++ b/usr.sbin/bhyve/qemu_fwcfg.c
@@ -524,6 +524,7 @@
 	struct qemu_fwcfg_user_file *fwcfg_file;
 	struct stat sb;
 	const char *opt_ptr, *opt_end;
+	ssize_t bytes_read;
 	int fd;
 	
 	fwcfg_file = malloc(sizeof(*fwcfg_file));
@@ -593,17 +594,19 @@
 			close(fd);
 			return (ENOMEM);
 		}
-		fwcfg_file->size = read(fd, fwcfg_file->data, sb.st_size);
-		if ((ssize_t)fwcfg_file->size < 0) {
+		bytes_read = read(fd, fwcfg_file->data, sb.st_size);
+		if (bytes_read < 0) {
 			warn("Unable to read file \"%s\"", opt_ptr);
 			free(fwcfg_file->data);
 			close(fd);
 			return (-1);
-		} else if (fwcfg_file->size < sb.st_size) {
+		} else if (bytes_read < sb.st_size) {
 			warnx("Only read %u bytes of file \"%s\"",
 			    fwcfg_file->size, opt_ptr);
 		}
 
+		fwcfg_file->size = bytes_read;
+
 		close(fd);
 	} else {
 		qemu_fwcfg_usage(opt);