Re: [PATCH] virtio-spec: Define virtio-mmio registers as LE

[Pawel Moll]

On Fri, 2013-03-01 at 10:41 +0000, Marc Zyngier wrote:
> On 14/02/13 10:54, Pawel Moll wrote:
> > To solve the never-ending confusions between hosts and guests
> > of different endianess, define all virtio-mmio registers as LE.
> > 
> > This change should be safe at this stage, because no known
> > working mixed-endian system exists so there is virtually no
> > risk of breaking compatibility.
> > 
> > Signed-off-by: Pawel Moll <pawel.moll@xxxxxxx>
>
> Shouldn't we exclude the config space? PCI defines it as guest-endian,
> and the above tends to indicate that it should be LE with MMIO.

The spec says: "Device-specific configuration space starts at an offset
0x100 and is accessed with byte alignment. Its meaning and size depends
on the device and the driver."

I would hope that "accessed with byte alignment" is enough of a clue in
this subject, but if you think otherwise I can add a sentence stating
this explicitly.

Having said that, Rusty was contemplating enforcing LE config space in
the new PCI layout...

PaweÅ


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