[libvirt] [PATCH v2 24/25] qemu: Support scsi controller model=virtio-{non-}transitional

[Andrea Bolognani]

On Wed, 2019-01-30 at 17:38 +0100, Pavel Hrdina wrote:
> On Tue, Jan 29, 2019 at 04:32:09PM +0100, Andrea Bolognani wrote:
> > >                    <value>virtio-scsi</value>
> > >                    <value>lsisas1078</value>
> > > +                  <value>virtio-transitional</value>
> > > +                  <value>virtio-non-transitional</value>
> > 
> > As mentioned during the previous round of reviews, I think we should
> > support model='virtio' (which would behave the same as the existing
> > model='virtio-scsi') in order to have a nice, consistent experience
> > for users and management application developers.
> 
> If we add model='virtio' we should always translate it back to
> 'virtio-scsi'.  It's not a new model or new feature, it's just a
> different name for existing model and we should not break management
> applications that are already using 'virtio-scsi'.  It would be
> basically only alias.

Definitely.

> The question is whether it's useful, if
> management application starts using 'virtio' when creating new guest it
> would still had to be able to parse 'virtio-scsi' and my guess is that
> it would not help at all.

I agree that the value proposition is not that impressive once
you've established the above.

That said, implementing it is only going to take a couple of lines
of code and it will allow applications that can afford to require
very recent libvirt to only special-case SCSI controllers when
parsing the configuration, instead of both when parsing and when
formatting.

I guess I just don't see a reason *not* to implement it. But if
Cole doesn't want to go through with it that's fine, I can just
post patches later myself :)

-- 
Andrea Bolognani / Red Hat / Virtualization