Re: [PATCH 0/3] virtio-mmio: handle BE guests on LE hosts

Michael S. Tsirkin
2013-10-14T12:50:59Z

On Mon, Oct 14, 2013 at 01:36:12PM +0100, Marc Zyngier wrote:
> On 14/10/13 09:21, Rusty Russell wrote:
> > Marc Zyngier <marc.zyngier@arm.com> writes:
> >> This small patch series adds just enough kernel infrastructure and
> >> fixes to allow a BE guest to use virtio-mmio on a LE host, provided
> >> that the host actually supports such madness.
> >>
> >> This has been tested on arm64, with some fixes to KVM and a set of
> >> changes to kvmtool, both which I am posting separately.
> >
> > OK, so I already have a patch which supports config space accessors.
> > I've posted the series below, and since you want it, I'll put it in
> > virtio-next after more testing and rebasing...
>
> Yes, that's definitely something I'd like to see being merged, as it
> would allow me to drop a significant chunk of changes.
>
> > But we won't be using feature bits for endianness, since we're defining
> > endian in the 1.0 spec (whether LE-everywhere or LE-for-mmio-and-PCI is
> > still debated). Since we need to guess for backwards compat anyway,
> > let's keep doing this until v1.0?
>
> When is 1.0 going to happen? When will actual implementation of drivers
> and devices show up in my favourite platform emulation?
>
> Having a grand plan for the future is great, but I need something
> working right now, or at least fairly soonish... And I need it to be
> backward compatible, as none of the above is going to show up overnight.
> > (Yeah, I made this mess with "native endian". I promise I have learnt
> > my lesson).
>
> Paracetamol bill coming you way... ;-)
>
> M.
> --
> Jazz is not dead. It just smells funny...

You can help by reviewing the proposals here:

mmio specific parts:
https://www.oasis-open.org/apps/org/workgroup/virtio/email/archives/201310/msg00123.html

generic changes:
http://markmail.org/search/?q=subject%3A%22%5BPATCH%5D%20configuration%20space%20endian-ness%22+list%3A%22org.oasis-open.lists.virtio%22

http://markmail.org/search/?q=subject%3A%22%5BPATCH%5D%20virtqueue%20endian-ness%22+list%3A%22org.oasis-open.lists.virtio%22

These are incremental patches against the current draft -
reviewing it would also be helpful:

https://tools.oasis-open.org/version-control/svn/virtio

We discuss virtio implementation issues at
virtio-dev@lists.oasis-open.org

--
MST