Re: PV drivers in HVM DomU

[Jean-Yves Migeon <jeanyves.migeon%free.fr@localhost>]

On 27.09.2011 19:22, David Howland wrote:
> Still a Xen newb but by my understanding, when I run a guest under Xen
> HVM, I can increase performance dramatically by using PV "drivers" to
> access network and disk (thus avoiding QEMU emulated devices). This is
> usually recommended in Windows, for example.

This is recommended everywhere :)

> So, is it possible or advisable to try and compile xenbus, xennet, and
> xbd into a GENERIC kernel?
>
> I am running GENERIC under HVM right now so I can use all four cores.

It might be possible, but you won't get far anyway: there is minimal 
work to get done (mostly code refactorization) before PV drivers can be 
used under a HVM domain.

This is the kind of stuff you do when you want to have the "best of both 
worlds": memory is managed at hardware level via HVM, and devices use PV 
to avoid emulation overhead. As NetBSD got PV support very early, there 
wasn't much push to mix HVM and PV; we will get there eventually though.

--
Jean-Yves Migeon
jeanyves.migeon%free.fr@localhost