[CentOS] Xen cpu requirements

Wed Jul 14 19:28:06 UTC 2010
Stephen Harris <lists at spuddy.org>

On Wed, Jul 14, 2010 at 02:20:10PM -0500, Victor Padro wrote:
> they're not explicit as I stated but perhaps it just states as VT-D or
> something that you may overlooked it.

VT-d (Virtualization Technology for Directed I/O) is virtualization
for devices.  With this it's possible for a guest OS to have direct
exclusive access to hardware devices (maybe one of the USB controllers,
or a disk controller).  This is, really, a layer violation but it can be
a performance gain or allow VMs to access hardware that the hypervisor
can not emulate.  My machine, apparently, supports VT-d in the BIOS but
either the chipset (H55) doesn't support it or something else is wrong;
the capability isn't available to the hypervisor.

This isn't needed for CPU virtualization to work.