Re: [Qemu-devel] [PATCH] spapr_pci: fail gracefully with non-pseries machine types

[David Gibson <david@gibson.dropbear.id.au>]

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On Fri, Oct 06, 2017 at 05:09:04PM +0200, Greg Kurz wrote:
> QEMU currently crashes when the user tries to add a spapr-pci-host-bridge
> on a non-pseries machine:
> 
> $ qemu-system-ppc64 -M ppce500 -device spapr-pci-host-bridge,index=1
> hw/ppc/spapr_pci.c:1535:spapr_phb_realize:
> Object 0x1003dacae60 is not an instance of type spapr-machine
> Aborted (core dumped)
> 
> The same thing happens with the deprecated but still available child type
> spapr-pci-vfio-host-bridge.
> 
> Fix both by checking the machine type with object_dynamic_cast().
> 
> Signed-off-by: Greg Kurz <groug@kaod.org>



> ---
>  hw/ppc/spapr_pci.c |    8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c
> index 5049ced4e8b4..9e85106f51f8 100644
> --- a/hw/ppc/spapr_pci.c
> +++ b/hw/ppc/spapr_pci.c
> @@ -1507,7 +1507,7 @@ static void spapr_pci_unplug_request(HotplugHandler *plug_handler,
>  
>  static void spapr_phb_realize(DeviceState *dev, Error **errp)
>  {
> -    sPAPRMachineState *spapr = SPAPR_MACHINE(qdev_get_machine());
> +    sPAPRMachineState *spapr;
>      SysBusDevice *s = SYS_BUS_DEVICE(dev);
>      sPAPRPHBState *sphb = SPAPR_PCI_HOST_BRIDGE(s);
>      PCIHostState *phb = PCI_HOST_BRIDGE(s);
> @@ -1519,6 +1519,12 @@ static void spapr_phb_realize(DeviceState *dev, Error **errp)
>      const unsigned windows_supported =
>          sphb->ddw_enabled ? SPAPR_PCI_DMA_MAX_WINDOWS : 1;
>  
> +    spapr = (sPAPRMachineState *) qdev_get_machine();
> +    if (!object_dynamic_cast((Object *) spapr, TYPE_SPAPR_MACHINE)) {
> +        error_setg(errp, TYPE_SPAPR_PCI_HOST_BRIDGE " needs a pseries machine");
> +        return;
> +    }

This is slightly clunky.  You could instead use OBJECT_CHECK in the
initializer, then just if (!spapr) here.

> +
>      if (sphb->index != (uint32_t)-1) {
>          sPAPRMachineClass *smc = SPAPR_MACHINE_GET_CLASS(spapr);
>          Error *local_err = NULL;
> 


-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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