From mboxrd@z Thu Jan  1 00:00:00 1970
From: pawel.moll@arm.com (Pawel Moll)
Date: Mon, 14 Oct 2013 11:50:59 +0100
Subject: [PATCH 0/3] virtio-mmio: handle BE guests on LE hosts
In-Reply-To: <20131014104604.GC30954@redhat.com>
References: <1381502171-8187-1-git-send-email-marc.zyngier@arm.com>
 <20131012182837.GC2089@redhat.com> <525BAA40.8070103@arm.com>
 <20131014085931.GB30954@redhat.com> <1381741495.3247.18.camel@hornet>
 <20131014104604.GC30954@redhat.com>
Message-ID: <1381747859.3247.33.camel@hornet>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Mon, 2013-10-14 at 11:46 +0100, Michael S. Tsirkin wrote:
> What I meant is that under the proposed scheme, users with
> existing v1 drivers must configure a v1 device explicitly.
> 
> According to the plan, drivers will be updated so they can
> work with both v1 devices and new v2 devices.
> 
> But if you configure a v2 device, old drivers
> will not work.

That's correct, yes. If qemu 2015(16? 17?).01 will provide v2 devices
only, kernel 3.11 is not going to recognize any of them.

What will happen in reality, though, is that the implementation of the
Linux v1/v2 driver will pre-date *any* v2 device by far. First
implementation of v1 devices appeared almost 2 years after the driver
appeared. It will take year for people to upgrade to v2, and probably
only after they experience problems with page-based addressing mode.

I think I can live with this.

Pawe?