Informations on using UEFI in Cloudstack (#248)

* Added informations for using UEFI in VMs

some further information for using uefi in cloudstack

* Update kvm.rst

* Update kvm.rst

* Update kvm.rst

Co-authored-by: Rohit Yadav <rohityadav89@gmail.com>

Author: Hudratronium

source/installguide/hypervisor/kvm.rst

@@ -1418,6 +1418,18 @@ replace your version of qemu-img with one which has been patched to include the
 switch.
 
 
+UEFI legacy / secureboot
+^^^^^^^^^^^^^^^^^^^^^^^^
+
+For deploying instances using UEFI legacy / secureboot, there are some further tasks to
+perform.
+You can find further informations regarding prerequisites at the CloudStack Wiki
+(https://cwiki.apache.org/confluence/display/CLOUDSTACK/Enable+UEFI+booting+for+Instance)
+as well as limitations for using UEFI in CloudStack.
+The options to deploy a instances using UEFI can be found in the "Advanced Mode" section 
+of the instance deployment wizard.
+
+
 Add the host to CloudStack
 ~~~~~~~~~~~~~~~~~~~~~~~~~~