paravirtualization


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paravirtualization

The modification of the source code of an OS in order to run as a guest OS in a virtual machine (VM) environment. Calls to the hardware from the guest OS are replaced with calls to the VM monitor (VMM). Several operating systems, such as Linux, OpenBSD, FreeBSD and OpenSolaris, were paravirtualized for the Xen VM monitor (see Xen).

Hardware Virtualization Changed the Game
In 2004 and 2006, Intel and AMD added hardware virtualization respectively, and unless VMs are running in ancient CPUs, the guest OS does not need to be paravirtualized. See virtual machine and hardware virtualization.


Paravirtualized Guests
The difference between a paravirtualized guest (above) and the emulation method (below) is the "device drivers." In a paravirtualized OS, the drivers are replaced with calls to the VM monitor (VMM) interface. For more on the VM monitor, see virtual machine monitor.







Emulated Hardware
If the VM monitor emulates the hardware, the guest OS can run without modification. The VM monitor presents a "device model" to the guest OS, which emulates the hardware.
References in periodicals archive ?
Pre-virtualization combines the advantages of a full-virtualization approach with the efficiency of a paravirtualization approach.
There are two basic models for this system virtualization: full virtualization, or a complete simulation of underlying hardware, and paravirtualization, which offers a "mostly similar" model of the underlying hardware.
With device paravirtualization, there is agreement between the hypervisor and the guest on how communications will progress.
8220;SierraVisor provides affordable, high-performance paravirtualization for ARM-based hardware developers,” said Gopu Subramanian, CTO of Sierraware.
Paravirtualization is the default approach employed by Xen systems and is supported, but not required, within Microsoft's Hyper-V.
com, 2007)) as well as some form of paravirtualization (Pralavirtualization on Wikipedia.
Full virtualization and paravirtualization are not the only approaches being taken.