Re: [Qemu-devel] [PATCH v3] hw/i386: Deprecate the machines pc-0.10 to pc-1.2

["Michael S. Tsirkin" <mst@redhat.com>]

On Thu, Jul 13, 2017 at 02:30:06AM +0200, Laszlo Ersek wrote:
> On 07/12/17 10:22, Thomas Huth wrote:
> > We don't want to carry along old machine types forever. If we are able to
> > remove the pc machines up to 0.13 one day for example, this would allow
> > us to eventually kill the code for rombar=0 (i.e. where QEMU copies ROM
> > BARs directly to low memory). Everything up to pc-1.2 is also known to
> > have issues with migration.  So let's start with a deprecation message
> > for the old machine types so that the (hopefully) few users of these old
> > systems start switching over to newer machine types instead.
> > 
> > Signed-off-by: Thomas Huth <thuth@redhat.com>
> > ---
> >  Note: Even if we mark all these old machines as deprecated, this ofcourse
> >  doesn't mean that we also have to remove them all at once later when we
> >  decide to finally really remove some. We could then also start by removing
> >  0.10 and 0.11 only, for example (since there should really be no users left
> >  for these), or only up to 0.13 (to be able to kill rombar=0).
> 
> On a tangent: "rombar=0" shouldn't be killed before the libvirt domain
> XML regains the ability to say, "don't load any oprom for this device".
> Please see <https://bugzilla.redhat.com/show_bug.cgi?id=1425058>.
> 
> (Please note that it is not lost on me that rombar=0 is a poor
> substitute for romfile='', but currently rombar=0 is the only fallback
> through libvirt. See the BZ pls.)
> 
> Thanks
> Laszlo

rombar=0 would start meaning "no ROM", not "no BAR but still add a
rom".