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

[Eduardo Habkost]

On Tue, Oct 16, 2018 at 08:48:16AM +0200, Gerd Hoffmann wrote:
>   Hi,
> 
> > I don't know.  The `disable-modern` option already exists but I
> > don't know who would want to use it.
> 
> Compat property for old (2.6 & older) machine types.
> 
> > > Right - maybe a flag to disable modern interface is enough.
> > > We thus get two types:
> > > - transitional (legacy)
> > > - non-transitional (modern)
> > > which matches spec nicely.
> > 
> > I would agree with the removal of virtio-*-0.9 only if we decide
> > to drop support for disable-modern=true.
> 
> 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).


> 
> > 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.

-- 
Eduardo