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Date: Tue, 23 Oct 2012 10:41:16 +0200
From: Gerd Hoffmann <kraxel@redhat.com>
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Subject: Re: [Qemu-devel] qemu <-> libvirt interaction broken
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To: Peter Maydell <peter.maydell@linaro.org>
Cc: "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>, Aurelien Jarno <aurelien@aurel32.net>

On 10/23/12 10:19, Peter Maydell wrote:
> On 23 October 2012 08:03, Gerd Hoffmann <kraxel@redhat.com> wrote:
>> On 10/22/12 15:51, Peter Maydell wrote:
>>> On 22 October 2012 14:28, Gerd Hoffmann <kraxel@redhat.com> wrote:
>>>> Commit 585f60368f23e6603cf86cfdaeceb89d1169f4b8 appearently breaks the
>>>> libvirt feature detection, my guests fail to start with this message:
>>>>
>>>> error: Failed to start domain fedora-org-virtio
>>>> error: internal error qemu does not support SGA
>>>>
>>>> Running libvirt-0.10.2-2.el6.x86_64
>>>
>>> Yeah, this is the commit that means you need an updated libvirt
>>> from this point on (and in particular for qemu-1.3).
>>
>> Well, only problem is that 0.10.2 already is the latest libvirt release.
>>  Was it really intentional to break things like this?
> 
> This change was postponed to after 1.2 was released to
> give libvirt a chance to wean itself off parsing our --help
> output.

Yea, I know this has been the plan for a long time and I agree that it
is a good move.

Only problem is that the switch didn't happen yet.  The bits might be
landed in libvirt/master, but there is no release with this yet and thus
libvirt versions using QOM for feature detection didn't find the way yet
into distributions.

IMO it is a bit early to stop caring about -help output compatibility in
qemu.

cheers,
  Gerd