From mboxrd@z Thu Jan  1 00:00:00 1970
From: Pawel Moll <pawel.moll@arm.com>
Subject: Re: [PATCH 0/3] virtio-mmio: handle BE guests on LE hosts
Date: Mon, 14 Oct 2013 10:04:55 +0100
Message-ID: <1381741495.3247.18.camel@hornet>
References: <1381502171-8187-1-git-send-email-marc.zyngier@arm.com>
	 <20131012182837.GC2089@redhat.com> <525BAA40.8070103@arm.com>
	 <20131014085931.GB30954@redhat.com>
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Cc: Marc Zyngier <Marc.Zyngier@arm.com>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>,
	"kvmarm@lists.cs.columbia.edu" <kvmarm@lists.cs.columbia.edu>,
	"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
	Rusty Russell <rusty@rustcorp.com.au>
To: "Michael S. Tsirkin" <mst@redhat.com>
Return-path: <kvm-owner@vger.kernel.org>
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On Mon, 2013-10-14 at 09:59 +0100, Michael S. Tsirkin wrote:
> On Mon, Oct 14, 2013 at 09:24:32AM +0100, Marc Zyngier wrote:
> > Hi Michael,
> >=20
> > On 12/10/13 19:28, Michael S. Tsirkin wrote:
> > > On Fri, Oct 11, 2013 at 03:36:08PM +0100, Marc Zyngier wrote:
> > >> This small patch series adds just enough kernel infrastructure a=
nd
> > >> fixes to allow a BE guest to use virtio-mmio on a LE host, provi=
ded
> > >> 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.
> > >>
> > >> A branch containing all the relevant changes is at:
> > >> git://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms.=
git kvm-arm64/be-on-le-3.12-rc4
> > >>
> > >> Cc: Rusty Russell <rusty@rustcorp.com.au>
> > >> Cc: Michael S. Tsirkin <mst@redhat.com>
> > >> Cc: Pawel Moll <pawel.moll@arm.com>
> > >=20
> > > We are changing the spec to make everything LE instead of
> > > the native endian.
> > >=20
> > > I think that'll fix the issue in a cleaner way.
> >=20
> > While I agree that it would solve the issue completely, it would al=
so
> > break all BE users. Is that really an option?
>=20
> I proposed several ways to create "transitional devices"
> which can detect and switch to old interface at run-time.
>=20
> Pawel thinks that's not necessary so ...

Don't wipe yourself with my name, please.

You forgot to mention that the devices are versioned and the behavior o=
f
the legacy devices remains unchanged. No existing implementation will b=
e
broken.

Pawe=C5=82