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

[Gerd Hoffmann]

On 12/14/09 21:43, Michael S. Tsirkin wrote:
> What do we put in e.g. 0.11 compat? Any features we enable
> there might not be supported by host.

compat properties as usual?

Sorry, I still fail to see your problem.

You'll have a 'disable' bitmap.  Fill it via 'features=<bitmap-prop>'. 
Or using separate properties for each feature.

qemu goes figure host_features.  When done it masks out the features 
disabled via properties.  The result is used as final feature bitmap.

-M pc-0.11 will disable hw_checksum
management software can do it too via -device virtio-net-pci,... if some 
machines in the pool don't support it.  And of course qemu will disable 
it on its own in case the host kernel doesn't support it.

cheers,
  Gerd