Re: Balloon driver?

[Carsten Otte <cotte-tA70FqPdS9bQT0dZR+AlfA@public.gmane.org>]

Dor Laor wrote:
> I agree that pci interface isn't ideal, the advantage is that platforms
> that do support pci don't have to implement a virtualized bus, and pci
> is PnP device. This was the motivation behind using it, especially for
> Windows.
In understand that requirement, and I think being able to surface 
paravirtual functions/devices to the guest as PCI device needs to be a 
key feature. For windows guests.

> Now that more platforms are joining the KVM wagon, we should define a
> common bus. PCI was a overkill anyway - its irq are shared and we don't
> have to use its io/mmio areas.
> Do you guys have something to start with?
We do have something basic, our vdev bus. The bad thing is, it is 
platform specific. I really prefer to aim for an idea that Arnd came 
up with when discussing this issue:
We could define a virtual device bus. We would have platform specific 
bus implementations which rely on hypercalls, interrupts, and shared 
memory in the pure paravirtual case. And we need a second bus driver, 
which is based on a pci device. Just similar to the situation where a 
PCI device is a USB host adapter.
Now functionality like device drivers can sit on top of the 
abstraction layer. We need to invent a similar abstraction on the 
hypervisor side, which is a tricky task indeed.
The best approach into this direction I have seen so far is not our 
own vdev thing but Rusty's virtio infrastructure. That's what I think 
I would start with.

so long,
Carsten

-------------------------------------------------------------------------
This SF.net email is sponsored by DB2 Express
Download DB2 Express C - the FREE version of DB2 express and take
control of your XML. No limits. Just data. Click to get it now.
http://sourceforge.net/powerbar/db2/