Re: [Qemu-devel] [PATCH] virtio: Provide version-specific variants of virtio PCI devices

[Gerd Hoffmann]

  Hi,

> > See above.  We can't drop disable-modern.
> 
> Good point.  But this doesn't require it to be a supported device
> option for users/management.  Maybe we should rename it to
> "x-disable-modern" (but that's a separate discussion).

I think it would be more useful to allow properties being tagged as
"no-user", simliar to devices which we do not want be created via
-device.

> > > If we still want to provide a legacy-only virtio device, it should be
> > > a separate device type.
> > 
> > I can't see a reason why we should provide legacy-only virtio devices.
> 
> If the only reason for disable-modern to exist is for internal
> usage by machine-type code, I agree we don't need the -0.9 device
> types.

In the early virtio-1.0 days it was required for testing.  We had one or
two releases with virtio-1.0 support merged but not (yet) turned on by
default, so you had to use disable-modern=off to enable virtio-1.0
support.  That use case is gone though since we flipped the default.

cheers,
  Gerd