Amazon Machine Images: HVM or PV?  Learn the differences between
HVM and PV for Amazon Machine Images.  Amazon Machine Images
(AMIs) have a virtualization type of "HVM" or "PV." What is the
difference and which should I choose?  Steve MillidgeSteve
Millidge  Under the covers, AWS runs the Xen hypervisor on the
bare metal of its servers. Xen has the capability to virtualize
in two ways: Hardware Virtual Machine (HVM) or
paravirtualization (PV).  Paravirtualization is a lightweight
form of virtualization which differs from HVM in that it doesn't
require any virtualization extensions from the host CPU. If your
host server doesn't have Intel VT or AMD-V hardware extensions,
then you'll need your guest to be paravirtualized.  PV does,
however require that a guest OS has a "Xen-PV-enabled kernel" as
well as PV drivers, meaning that the guests know that they are
running in a hypervisor.  HVM guests are fully virtualized, so
the underlying hardware has to be emulated for the guests to
use, incurring performance cost,