Re: [PATCH 3/3] hw/pci: Consider reserved slots mask when checking PCI bus is full

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

On Tue, Jul 07, 2026 at 10:40:50AM +0200, Philippe Mathieu-Daudé wrote:
> Do not consider reserved slots as available.
>

Philippe this is not how commit logs are supposed to look,
just repeating what the patch does with no explanation.
You know that.
 
> Fixes: 8b8849844fd ("pci: add reserved slot check to do_pci_register_device")

especially if it's supposedly a regression?

> Reported-by: Thomas Huth <thuth@redhat.com>
> Signed-off-by: Philippe Mathieu-Daudé <philmd@oss.qualcomm.com>
> ---
>  hw/pci/pci.c | 17 +++++++++++++++++
>  1 file changed, 17 insertions(+)
> 
> diff --git a/hw/pci/pci.c b/hw/pci/pci.c
> index b04e94a150b..2e5412137b3 100644
> --- a/hw/pci/pci.c
> +++ b/hw/pci/pci.c
> @@ -62,6 +62,7 @@ static char *pcibus_get_dev_path(DeviceState *dev);
>  static char *pcibus_get_fw_dev_path(DeviceState *dev);
>  static void pcibus_reset_hold(Object *obj, ResetType type);
>  static bool pcie_has_upstream_port(PCIDevice *dev);
> +static bool pci_bus_is_full(const BusState *qbus);
>  
>  static void prop_pci_busnr_get(Object *obj, Visitor *v, const char *name,
>                                 void *opaque, Error **errp)
> @@ -293,6 +294,7 @@ static void pci_bus_class_init(ObjectClass *klass, const void *data)
>      k->print_dev = pcibus_dev_print;
>      k->get_dev_path = pcibus_get_dev_path;
>      k->get_fw_dev_path = pcibus_get_fw_dev_path;
> +    k->is_full = pci_bus_is_full;
>      k->realize = pci_bus_realize;
>      k->unrealize = pci_bus_unrealize;
>  
> @@ -1329,6 +1331,21 @@ void pci_bus_clear_slot_reserved_mask(PCIBus *bus, uint32_t mask)
>      bus->slot_reserved_mask &= ~mask;
>  }
>  
> +static bool pci_bus_is_full(const BusState *qbus)
> +{
> +    const PCIBus *bus = PCI_BUS(qbus);
> +
> +    for (int i = 0; i < PCI_DEVFN_MAX; i += PCI_FUNC_MAX) {
> +        if (pci_bus_devfn_reserved(bus, i)) {
> +            continue;
> +        }
> +        if (pci_bus_devfn_available(bus, i)) {
> +            return false;
> +        }
> +    }
> +    return true;
> +}
> +
>  /* -1 for devfn means auto assign */
>  static PCIDevice *do_pci_register_device(PCIDevice *pci_dev,
>                                           const char *name, int devfn,
> -- 
> 2.53.0