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Date: Mon, 14 Dec 2009 21:40:28 +0100
From: Gerd Hoffmann <kraxel@redhat.com>
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Subject: Re: [Qemu-devel] Re: [PATCH RFC] virtio: add features qdev property
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To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Markus Armbruster <armbru@redhat.com>, qemu-devel@nongnu.org

On 12/14/09 20:17, Michael S. Tsirkin wrote:
> On Mon, Dec 14, 2009 at 06:18:29PM +0100, Gerd Hoffmann wrote:
>> On 12/14/09 17:23, Michael S. Tsirkin wrote:
>>> On Mon, Dec 14, 2009 at 04:01:33PM +0100, Gerd Hoffmann wrote:
>>> So how do you do this?
>>> Assume we have -disable_hw_csum.
>>> We want new machine type to have it off, right?
>>> But now you run qemu on host which does
>>> not support hw_csum. With your suggestion
>>> it will not enable hw csum?
>>
>> I have trouble getting the setup you are talking about ...
>>
>> Sounds like hw_csum could be enabled/disabled depending on the hardware
>> capabilities on the host.  Is that correct?
>>
>> cheers,
>>    Gerd
>
> This currently depends on version of tun driver in the host.

So this has nothing to do with -M pc-0.11 backward compatibility, right? 
  You'll hit this when migrating 0.12 -> 0.12 with different host 
kernels, right?  And the common bit here is that both issues can be 
handled by configuring virtio feature bits via properties, right?

What was the question again?

cheers,
   Gerd