Re: [Qemu-ppc] [PULL 25/26] spapr_pci: factorize the use of SPAPR_MACHINE_GET_CLASS()

[Cédric Le Goater]

On 08/24/2018 05:09 PM, Peter Maydell wrote:
> On 21 August 2018 at 05:33, David Gibson <address@hidden> wrote:
>> From: Cédric Le Goater <address@hidden>
>>
>> It should save us some CPU cycles as these routines perform a lot of
>> checks.
>>
>> Signed-off-by: Cédric Le Goater <address@hidden>
>> Signed-off-by: David Gibson <address@hidden>
>> ---
>>  hw/ppc/spapr_pci.c | 11 ++++++-----
>>  1 file changed, 6 insertions(+), 5 deletions(-)
> 
> Hi; Coverity points out in CID 1395183 that there's a bug in
> this part of this patch:
> 
>> @@ -1558,6 +1559,7 @@ static void spapr_phb_realize(DeviceState *dev, Error 
>> **errp)
>>      sPAPRMachineState *spapr =
>>          (sPAPRMachineState *) object_dynamic_cast(qdev_get_machine(),
>>                                                    TYPE_SPAPR_MACHINE);
>> +    sPAPRMachineClass *smc = SPAPR_MACHINE_GET_CLASS(spapr);
> 
> This has moved the call to SPAPR_MACHINE_GET_CLASS() above
> the check for "is spapr NULL", which is wrong, because it
> will unconditionally dereference the pointer you pass to it.

I see. This is a simple fix but the root reason for this check is 
commit f7d6bfcdc0fe ("spapr_pci: fail gracefully with non-pseries 
machine types"). 

Is there a way to specify which device type can or can not be 
plugged on a machine ? 

I suppose we cannot use : 

        machine_class_allow_dynamic_sysbus_dev() 

for cold plugged devices. Or can we ? That would be better.

Thanks,

C.