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Date: Wed, 7 Jan 2015 17:29:49 +0100
From: Cornelia Huck <cornelia.huck@de.ibm.com>
Message-ID: <20150107172949.11f374bf.cornelia.huck@de.ibm.com>
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Subject: Re: [Qemu-devel] [PATCH RFC v6 19/20] virtio-blk: revision specific
	feature bits
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To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: thuth@linux.vnet.ibm.com, rusty@rustcorp.com.au, qemu-devel@nongnu.org, virtualization@lists.linux-foundation.org

On Sun, 28 Dec 2014 12:24:46 +0200
"Michael S. Tsirkin" <mst@redhat.com> wrote:

> On Thu, Dec 11, 2014 at 02:25:21PM +0100, Cornelia Huck wrote:
> > Wire up virtio-blk to provide different feature bit sets depending
> > on whether legacy or v1.0 has been requested.
> > 
> > Note that VERSION_1 is still disabled due to missing ANY_LAYOUT support.
> > 
> > Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
> 
> So we need some way for devices to tell transports
> not to negotiate rev 1.
> Does clearing VERSION_1 have this effect?
> 
I just noticed that my patch is running in circles here.

What we need is probably the transport-dependent maximum revision
checker (which at least for ccw is acting on a device) pass in the
requested revision and check if the feature bits for the revision
include VERSION_1. Does that make sense?