Re: [virtio-comment] virtio and endian-ness

[Pawel Moll <pawel.moll@arm.com>]

On Tue, 2013-08-20 at 15:11 +0100, Paolo Bonzini wrote:
> Il 20/08/2013 16:09, Pawel Moll ha scritto:
> > On Tue, 2013-08-20 at 15:03 +0100, Pawel Moll wrote:
> >> It must be possible to write a driver that drivers
> >> both the old and the new specs.
> > 
> > Should read: "... that drives devices complaint to both the old and the
> > new specs".
> 
> Both ways should be possible: write a driver for both old and new specs,
> and write a device for both old and new specs.
> 
> In both cases, the differences between old and new specs should be
> ideally hidden in the virtio layer, or more precisely in the virtio
> transport layer.  The virtio devices and drivers themselves should be
> unaffected.

First of all, I disagree with the assumption that the OASIS spec must
not bring any changes to the environment. I actually consider it an
opportunity to fix what was mis-designed, even for a price of changes
needed in at both sides of the equation.

Now, as to the "hidden in the transport layer"... By "driver" I meant
"virtio_mmio.c", which - I believe - is the transport layer you are
referring to. And this is what I want to change indeed with the
assumption that virtio_mmio v2 does *not* have to be compatible with
virtio_mmio v1. And I will be strongly against any attempts of making it
(*the MMIO device*) more complicated.

Paweł