Re: [PATCH] hw/pci: Avoid adding PCI devices to the "unattached" QOM tree node

[Igor Mammedov <imammedo@redhat.com>]

On Tue, 17 Feb 2026 07:55:12 +0100
Thomas Huth <thuth@redhat.com> wrote:

> From: Thomas Huth <thuth@redhat.com>
> 
> PCI devices that are added via pci_create_simple_multifunction(),
> pci_create_simple() or pci_init_nic_in_slot() currently show up
> under "/machine/unattached" in the QOM tree. This is somewhat ugly,
> the parent should rather be the PCI bus node instead, so let's add
> the proper relation here.
> 
> Signed-off-by: Thomas Huth <thuth@redhat.com>
> ---
>  hw/pci/pci.c | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
> 
> diff --git a/hw/pci/pci.c b/hw/pci/pci.c
> index 90d6d71efdc..2f4d2be50fd 100644
> --- a/hw/pci/pci.c
> +++ b/hw/pci/pci.c
> @@ -2071,6 +2071,15 @@ const pci_class_desc *get_class_desc(int class)
>      return desc;
>  }
>  
> +static void pci_dev_property_add_child(PCIBus *bus, const char *name,
> +                                       PCIDevice *dev)
> +{
> +    g_autofree char *childname = g_strdup_printf("%s[%d.%d]", name,
> +                                                 PCI_SLOT(dev->devfn),
> +                                                 PCI_FUNC(dev->devfn));
> +    object_property_add_child(OBJECT(bus), childname, OBJECT(dev));
> +}
> +
>  void pci_init_nic_devices(PCIBus *bus, const char *default_model)
>  {
>      qemu_create_nic_bus_devices(&bus->qbus, TYPE_PCI_DEVICE, default_model,
> @@ -2114,6 +2123,7 @@ bool pci_init_nic_in_slot(PCIBus *rootbus, const char *model,
>  
>      pci_dev = pci_new(devfn, model);
there are a few more places that have similar pattern, should we fix them to?

>      qdev_set_nic_properties(&pci_dev->qdev, nd);
> +    pci_dev_property_add_child(bus, model, pci_dev);

>      pci_realize_and_unref(pci_dev, bus, &error_fatal);
this one also takes bus as an argument, and then goes down to
 qdev_realize_and_unref->qdev_realize->qdev_set_parent_bus->bus_add_child
that eventually creates a link to device.

wouldn't pci_dev_property_add_child() create a duplicate entry
as a child with different name component there?

another question, should we 'fix' qdev_set_parent_bus->bus_add_child
to add a child instead of a link? That would do what patch intends
but consistently for all devices with parent bus.


>      return true;
>  }
> @@ -2412,6 +2422,8 @@ PCIDevice *pci_create_simple_multifunction(PCIBus *bus, int devfn,
>                                             const char *name)
>  {
>      PCIDevice *dev = pci_new_multifunction(devfn, name);
> +
> +    pci_dev_property_add_child(bus, name, dev);
>      pci_realize_and_unref(dev, bus, &error_fatal);
>      return dev;
>  }
> @@ -2419,6 +2431,8 @@ PCIDevice *pci_create_simple_multifunction(PCIBus *bus, int devfn,
>  PCIDevice *pci_create_simple(PCIBus *bus, int devfn, const char *name)
>  {
>      PCIDevice *dev = pci_new(devfn, name);
> +
> +    pci_dev_property_add_child(bus, name, dev);
>      pci_realize_and_unref(dev, bus, &error_fatal);
>      return dev;
>  }