Re: [Qemu-devel] [PATCH 28/35] kvm: x86: Introduce kvmclock device to save/restore its state

[Gerd Hoffmann]

On 01/18/11 18:09, Anthony Liguori wrote:
> On 01/18/2011 10:56 AM, Jan Kiszka wrote:
> > > The device model topology is 100% a hidden architectural detail.
> > This is true for the sysbus, it is obviously not the case for PCI and
> > similarly discoverable buses. There we have a guest-explorable topology
> > that is currently equivalent to the the qdev layout.
>
> But we also don't do PCI passthrough so we really haven't even explored
> how that maps in qdev. I don't know if qemu-kvm has attempted to
> qdev-ify it.

It is qdev-ified.  It is a normal pci device from qdev's point of view.

BTW: is there any reason why (vfio-based) pci passthrough couldn't work 
with tcg?

> The -device interface is a stable interface. Right now, you don't
> specify any type of identifier of the pci bus when you create a PCI
> device. It's implied in the interface.

Wrong.  You can specify the bus you want attach the device to via 
bus=<name>.  This is true for *every* device, including all pci devices. 
 If unspecified qdev uses the first bus it finds.

As long as there is a single pci bus only there is simply no need to 
specify it, thats why nobody does that today.  Once q35 finally arrives 
this will change of course.

cheers,
  Gerd