Need help for thesis on Xen - disabling HAP for benchmarking purposes

[Alexander Sascha]

Hi,

I'm a German student, writing my thesis on "Virtualization with Xen. 
Analysis and Comparision of Different Techniques such as 
Paravirtualization, Full Virtualization, and Utilization of Hardware 
Support Provided by the Processor".

I'd like to know how I can disable HAP/RVI/Nested Paging for 
benchmarking purposes. I read somewhere 
(http://markmail.org/message/bbnivuqx6vjz7jg4) that Xen developers 
decided to disable the global grub parameter introducing a per domain 
flag for HAP instead (hap=0/1).

I used virt-manager built in CentOS for setting up all domUs; 
virt-manager uses libvirt so that no "old-style" configuration files are 
stored in /etc/xen. I actually don't know how if libvirt-XML-files 
already support something like <hap>0</hap>. How would you proceed  to 
modify an already existing domain using libvirt/virt-manager?

I really do apologize for my "newbie ignorance". Thanks in advance for 
any useful help.

- Alex