Re: [Qemu-devel] Re: [PATCH RFC] virtio: add features qdev property

[Michael S. Tsirkin]

On Mon, Dec 14, 2009 at 04:01:33PM +0100, Gerd Hoffmann wrote:
> On 12/14/09 14:59, Michael S. Tsirkin wrote:
>> It's not an easy quesiton.
>> If we do it as disable bits, then we get incompatible
>> machines when running on different hosts.
>
> In case that one host supports feature which the other doesn't and the  
> feature isn't masked out?  Well, management failure I'd say.  The whole  
> point of the compat machine types (and properties used there) is to make  
> sure the vm's are compatible even in case the hosts run different  
> software versions.
>
> cheers,
>   Gerd


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?

-- 
MST