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

[Greg Kurz <groug@kaod.org>]

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On Sat, 7 Oct 2017 10:06:00 +0200
Greg Kurz <groug@kaod.org> wrote:

> On Sat, 7 Oct 2017 16:19:25 +1100
> David Gibson <david@gibson.dropbear.id.au> wrote:
> 
> > 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.
> >   
> 
> Unless I'm missing something, OBJECT_CHECK() is precisely what we're
> removing with this patch to avoid the runtime assert...
> 
> #define SPAPR_MACHINE(obj) \
>     OBJECT_CHECK(sPAPRMachineState, (obj), TYPE_SPAPR_MACHINE)
> 

Since we already do this in spapr-cpu-core, I guess I'll hide the ugliness
in some macro. I'll send another patch.

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


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