diff --git a/man7/vsock.7 b/man7/vsock.7
index 23c67548f..145057719 100644
--- a/man7/vsock.7
+++ b/man7/vsock.7
@@ -95,6 +95,7 @@ struct sockaddr_vm {
     unsigned short svm_reserved1;
     unsigned int   svm_port;       /* Port # in host byte order */
     unsigned int   svm_cid;        /* Address in host byte order */
+    unsigned char  svm_zero[];
 };
 .EE
 .in
@@ -113,6 +114,8 @@ Only a process with the
 capability may
 .BR bind (2)
 to these port numbers.
+.I svm_zero
+is always set to 0.
 .PP
 There are several special addresses:
 .B VMADDR_CID_ANY