On Wed, Sep 11, 2013 at 05:13:41PM +0300, Michael S. Tsirkin wrote:
> non-transitional devices should have been able to simply update
> revision ID to make sure legacy drivers are not loaded.
> Unfortunately, mistakes were made:
> - we didn't stress that drivers must check revision ID,
> and of course there's no easy way for drivers to
> test this failure path,
> so older versions of Windows drivers ignored revision
> (latest vision matches revision correctly)
> - CCW lacks revision ID field
>
> Both facts mean a non-transitional device would need
> a separate mechanism to prevent legacy drivers from
> loading.
> We aren't running out of device IDs yet, so
> let's use up some to resolve this.
>
> I incremented all IDs by 0x100 intentionally -
> for the PCI bindings, this should help remind people they can't
> just stick the Subsystem ID into the low byte of the Device ID.
>
> Signed-off-by: Michael S. Tsirkin <>
> ---
>
> Changes from v1:
> drop an unrelated chunk erroneously inserted here
>
> virtio-v1.0-wd01-part1-specification.txt | 74 +++++++++++++++++++-------------
> 1 file changed, 44 insertions(+), 30 deletions(-)
Reviewed-by: Stefan Hajnoczi <>
