Re: [Qemu-devel] [RFC 00/15] qmp: Report supported device types on 'query-machines'

[Marcel Apfelbaum]

On 11/24/2016 05:41 PM, Markus Armbruster wrote:
> Marcel Apfelbaum <address@hidden> writes:
>
> > On 11/24/2016 03:34 PM, Markus Armbruster wrote:
> > > Eduardo Habkost <address@hidden> writes:
> > >
> > > > On Wed, Nov 23, 2016 at 06:43:16PM +0200, Marcel Apfelbaum wrote:
> > > > > On 11/22/2016 03:11 AM, Eduardo Habkost wrote:
> > > > > > The Problem
> >
> > [...]
> >
> > > Our decision to have hybrid PCI/PCIe devices and buses breeds
> > > considerable complexity.  I wish we had avoided them, but I believe it's
> > > too late to change now.
> > >
> > > > > This still does not solve the problem that some devices makes
> > > > > sense only on a specific arch.
> >
> > Hi Markus,
> >
> > > Examples?
> >
> > One quick example would be that we don't want to see
> > Intel's IOH 3420 PCIe Root Port in an ARM machine,
> > or a pxb on a Q35 machine (in this case we want pxb-pcie)
>
> Such a device would be weird.  But would it be wrong?

Define wrong :)

 Wrong enough for
> QEMU to reject it?

QEMU accepts them and they even function correctly as far as I know.

  Unless QEMU rejects it, there's no reason not to
> list it as pluggable.

This is the gray area I can't argue. I do think that Eduardo's
work may present an opportunity to change QEMU's mantra:
"everything goes as long as it works" to "here is what this configuration 
supports".



Thanks,
Marcel

> > I do believe there are other examples, I'll try to think of more.
> >
> > Thanks,
> > Marcel
> >
> > [...]