On Mon, 20 Jul 2020 11:54:06 +0200 Halil Pasic <pa...@linux.ibm.com> wrote:
> On Tue, 7 Jul 2020 12:54:44 +0200 > Cornelia Huck <coh...@redhat.com> wrote: > > > As discussed in "virtio-fs: force virtio 1.x usage", it seems like > > a good idea to make sure that any new virtio device (which does not > > support legacy virtio) is indeed a non-transitional device, just to > > catch accidental misconfigurations. We can easily compile a list > > of virtio devices with legacy support and have transports verify > > in their plugged callbacks that legacy support is off for any device > > not in that list. > > > > Most new virtio devices force non-transitional already, so nothing > > changes for them. vhost-user-fs-pci even does not allow to configure > > a non-transitional device, so it is fine as well. > > > > One problematic device, however, is virtio-iommu-pci. It currently > > offers both the transitional and the non-transitional variety of the > > device, and does not force anything. I'm unsure whether we should > > consider transitional virtio-iommu unsupported, or if we should add > > some compat handling. (The support for legacy or not generally may > > change based upon the bus, IIUC, so I'm unsure how to come up with > > something generic.) > > > > Both patches look good to me (Acked-by: Halil Pasic > <pa...@linux.ibm.com>). I tend to agree with Davids comment on how > this information is coded: the more object oriented way would have > been to store this at the something like VirtioDeviceClass, but > Michael's argument stands. > > Another OO option would be to expose this as a virtio property. Would > enable introspection, and would also give the host admin means to > force non-legacy for transitional devices. But the juice is probably not > worth the squeeze. I agree, that would be a lot of hassle for exposing what is basically static information.
