diff --git a/vhost_user_block/src/main.rs b/vhost_user_block/src/main.rs
index c1e589770..79ad1aeac 100644
--- a/vhost_user_block/src/main.rs
+++ b/vhost_user_block/src/main.rs
@@ -25,7 +25,7 @@ fn main() {
                 .long("block-backend")
                 .help(vhost_user_block::SYNTAX)
                 .takes_value(true)
-                .min_values(1),
+                .required(true),
         )
         .get_matches();
 
diff --git a/vhost_user_net/src/main.rs b/vhost_user_net/src/main.rs
index e5457b388..91c027539 100644
--- a/vhost_user_net/src/main.rs
+++ b/vhost_user_net/src/main.rs
@@ -22,7 +22,7 @@ fn main() {
                 .long("net-backend")
                 .help(vhost_user_net::SYNTAX)
                 .takes_value(true)
-                .min_values(1),
+                .required(true),
         )
         .get_matches();