diff --git a/PVE/QemuServer.pm b/PVE/QemuServer.pm
index 8b09bcdc..1ccdccf9 100644
--- a/PVE/QemuServer.pm
+++ b/PVE/QemuServer.pm
@@ -1387,7 +1387,9 @@ sub kvm_user_version {
 
 }
 
-my $kernel_has_vhost_net = -c '/dev/vhost-net';
+sub kernel_has_vhost_net {
+    return -c '/dev/vhost-net';
+}
 
 sub valid_drive_names {
     # order is important - used to autoselect boot disk
@@ -1973,7 +1975,7 @@ sub print_netdev_full {
 
     my $vhostparam = '';
     if (is_native($arch)) {
-	$vhostparam = ',vhost=on' if $kernel_has_vhost_net && $net->{model} eq 'virtio';
+	$vhostparam = ',vhost=on' if kernel_has_vhost_net() && $net->{model} eq 'virtio';
     }
 
     my $vmname = $conf->{name} || "vm$vmid";
diff --git a/test/run_config2command_tests.pl b/test/run_config2command_tests.pl
index 96e67e5d..b0cad21d 100755
--- a/test/run_config2command_tests.pl
+++ b/test/run_config2command_tests.pl
@@ -110,6 +110,9 @@ $qemu_server_module->mock(
     kvm_version => sub {
 	return $current_test->{qemu_version} // $base_env->{real_qemu_version};
     },
+    kernel_has_vhost_net => sub {
+	return 1; # TODO: make this per-test configurable?
+    },
     get_host_arch => sub() {
 	return $current_test->{host_arch} // 'x86_64';
     },