On Wed, Sep 25, 2013 at 10:32:03AM +0200, Paolo Bonzini wrote:
> Il 25/09/2013 10:28, Michael S. Tsirkin ha scritto:
> > > Failure to start vhost (which is fatal for vhost-scsi,
> > > since there is no userspace fallback unlike vhost-net) could be reported
> > > by not acknowledging FEATURES_OK.
> >
> > I think what you are asking for really, is
> > DEVICE_OK flag that locks both features and rings
> > and enables device.
>
> Yes, you're right. Plus the fact that the device might not acknowledge
> DEVICE_OK, which renders the device unusable.
>
> There is a difference, though. What happens if a virtqueue is only
> enabled by a particular feature? FEATURES_OK would let the device
> disable discovery of that virtqueue. DEVICE_OK wouldn't.
>
> Paolo
Maybe we want two new steps: FEATURES_OK and DEVICE_OK?
> > It would have to be set from driver quite late in life.
