On Wed, Jul 01, 2020 at 06:19:17PM +0200, Cornelia Huck wrote: > On Tue, 30 Jun 2020 09:04:38 -0400 > "Michael S. Tsirkin" <m...@redhat.com> wrote: > > > On Tue, Jun 30, 2020 at 02:25:04PM +0200, Cornelia Huck wrote: > > > > What bothers me most is that you need to explicitly request a device to > > > be modern-only, while that should be the default for any newly added > > > device. Hence the approach with the centralized list of device types > > > mentioned in a parallel thread. The main problem with that is that the > > > proxy device starts getting realized before the virtio device with its > > > id is present... I failed to find a solution so far. But I'd really > > > like an approach that can work for all transports. > > > > So how about simply validating that the device is modern only, > > unless it's one of the whitelist? > > Who would do the validation, the virtio core? How can it distinguish > between transitional and non-transitional? But maybe I'm just not > getting your idea.
OK I've been thinking about two ideas, we can use them both: 1. virtio core: that can detect VIRTIO_1 being clear in virtio_validate_features. 2. transports: could use a core API to detect whether device can be a legacy one, to block device creation. > Also, ccw does not currently have a way to explicitly configure a > device non-transitional; the revisions can be used to fence off newer > features, going down to legacy-only, but fencing off older features is > not possible (that is only done by the device, if it has no legacy > support). I guess for ccw only option 1 works. -- MST
