On Mon, Oct 11, 2010 at 05:39:01PM +0200, Avi Kivity wrote:
> On 10/11/2010 05:30 PM, Stefan Hajnoczi wrote:
> >>
> >> It was discussed before, but I don't think we came to a conclusion. Are
> >> there any circumstances under which you don't want to set the
> >> QED_CF_BACKING_FORMAT flag?
> >
> >I suggest the following:
> >
> >QED_CF_BACKING_FORMAT_RAW = 0x1
> >
> >When set, the backing file is a raw image and should not be probed for
> >its file format. The default (unset) means that the backing image file
> >format may be probed.
> >
> >Now the backing_fmt_{offset,size} are no longer necessary.
>
> Should it not be an incompatible option? If the backing disk starts
> with a format magic, it will be probed by an older qemu,
> incorrectly.
Agreed, it should be a non-compat feature bit.
Stefan
