diff --git a/lib/hypervisor/hv_kvm.py b/lib/hypervisor/hv_kvm.py
index b2d158de8d095ddef53cf96cf8bc12d6403260a2..54bd557f4f4e18e69ce8a9cac28caedc8c528f03 100644
--- a/lib/hypervisor/hv_kvm.py
+++ b/lib/hypervisor/hv_kvm.py
@@ -1369,7 +1369,7 @@ class KVMHypervisor(hv_base.BaseHypervisor):
         kvm_cmd.extend(["-usbdevice", dev])
 
     if hvp[constants.HV_KVM_EXTRA]:
-      kvm_cmd.extend([hvp[constants.HV_KVM_EXTRA].split(" ")])
+      kvm_cmd.extend(hvp[constants.HV_KVM_EXTRA].split(" "))
 
     # Save the current instance nics, but defer their expansion as parameters,
     # as we'll need to generate executable temp files for them.
diff --git a/man/gnt-instance.rst b/man/gnt-instance.rst
index 196040416230cf6cf7b7d72be9d5c32637604798..daa35c078aecd3188c4f14ec0ab96e563f5d5424 100644
--- a/man/gnt-instance.rst
+++ b/man/gnt-instance.rst
@@ -715,7 +715,9 @@ kvm\_extra
     Valid for the KVM hypervisor.
 
     Any other option to the KVM hypervisor, useful tweaking anything
-    that Ganeti doesn't support.
+    that Ganeti doesn't support. Note that values set with this
+    parameter are split on a space character and currently don't support
+    quoting.
 
 machine\_version
     Valid for the KVM hypervisor.