Re: [Qemu-devel] [PATCH v2 10/10] qdev: Do not let the user try to device_add when it cannot work

[Markus Armbruster]

Marcel Apfelbaum <address@hidden> writes:

> On Tue, 2013-10-29 at 17:08 +0100, address@hidden wrote:
>> From: Markus Armbruster <address@hidden>
>> 
>> Such devices have always been unavailable and omitted from the list of
>> available devices shown by device_add help.  Until commit 18b6dad
>> silently broke the former, setting up nasty traps for unwary users,
>> like this one:
>> 
>>     $ qemu-system-x86_64 -nodefaults -monitor stdio -display none
>>     QEMU 1.6.50 monitor - type 'help' for more information
>>     (qemu) device_add apic
>>     Segmentation fault (core dumped)
>> 
>> I call that a regression.  Fix it.
>> 
>> Signed-off-by: Markus Armbruster <address@hidden>
>> ---
>>  qdev-monitor.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>> 
>> diff --git a/qdev-monitor.c b/qdev-monitor.c
>> index 36f6f09..c538fec 100644
>> --- a/qdev-monitor.c
>> +++ b/qdev-monitor.c
>> @@ -477,7 +477,7 @@ DeviceState *qdev_device_add(QemuOpts *opts)
>>          }
>>      }
>>  
>> -    if (!obj) {
>> +    if (!obj || DEVICE_CLASS(obj)->cannot_instantiate_with_device_add_yet) {
>>          qerror_report(QERR_INVALID_PARAMETER_VALUE, "driver", "device 
>> type");
>>          return NULL;
>>      }
> Minor comment, if you move the if statement after
>  k = DEVICE_CLASS(obj);
> you don't need the cast anymore.

Ignorant question: does DEVICE_CLASS(NULL) work and return NULL?

> Seems OK to me.
> Reviewed-by: Marcel Apfelbaum <address@hidden>

Thanks!