Re: PV drivers in HVM DomU

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Tue, Sep 27, 2011 at 01:22:35PM -0400, 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.
> 
> So, is it possible or advisable to try and compile xenbus, xennet,
> and xbd into a GENERIC kernel?

The needed bits are not there yet.
As I understand it, we need:
- a driver for the PCI device which shows up in a HVM guest, and which
  is the entry point to talk to the xenstore. xenbus would attach to this.
- A way to get events for xenbus's devices. I don't know exactly
  how they shows up; in my mind these don't need to be real
  interrupts; something like a software interrupt would work too.

I've not looked at all at the API this PCI device offers, and how events
are managed ...

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
--