Re: [Qemu-devel] [PATCH v7 08/25] x86-iommu: introduce parent class

[Marcel Apfelbaum]

On 05/23/2016 08:06 PM, David Kiarie wrote:
> On Tue, May 17, 2016 at 10:15 AM, Peter Xu <address@hidden> wrote:
> > Introducing parent class for intel-iommu devices named "x86-iommu". This
> > is preparation work to abstract shared functionalities out from Intel
> > and AMD IOMMUs. Currently, only the parent class is introduced. It does
> > nothing yet.
> >
> > Signed-off-by: Peter Xu <address@hidden>
> > ---
> >   hw/i386/Makefile.objs         |  2 +-

[...]

> > +
> > +static const TypeInfo x86_iommu_info = {
> > +    .name          = TYPE_X86_IOMMU_DEVICE,
> > +    .parent        = TYPE_SYS_BUS_DEVICE,
> > +    .instance_size = sizeof(X86IOMMUState),
> > +    .class_init    = x86_iommu_class_init,
> > +    .class_size    = sizeof(X86IOMMUClass),
> > +    .abstract      = true,
> > +};
>
> As I suspected am having some trouble parenting a PCI device from a
> Bus device but I will investigate further to see if I can manage
> something.

You cannot derive from both SYS_BUS_DEVICE and PCI_DEVICE.
You would need a composition; your device would be a SYS_BUS_DEVICE
and its state would include a PCI_DEVICE (or the other way around).
Then you can divide the responsibilities between them.

Thanks,
Marcel

> > +

[...]