On Mon, Dec 14, 2009 at 09:40:28PM +0100, Gerd Hoffmann wrote: > 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?
Yes, this does. With 0.11 you must not expose this even if supported by host. Otherwise you wnt be able to migrate to 0.11. > 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? Yes. > What was the question again? > > cheers, > Gerd What do we put in e.g. 0.11 compat? Any features we enable there might not be supported by host. -- MST
