Re: [Qemu-devel] [PATCH v4 10/10] qdev: Do not let the user try to device_add when it cannot work

[Markus Armbruster]

Andreas Färber <address@hidden> writes:

> Am 28.11.2013 17:27, schrieb address@hidden:
>> 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>
>> Reviewed-by: Marcel Apfelbaum <address@hidden>
>> ---
>>  qdev-monitor.c | 5 +++++
>>  1 file changed, 5 insertions(+)
>> 
>> diff --git a/qdev-monitor.c b/qdev-monitor.c
>> index e6825ba..177b849 100644
>> --- a/qdev-monitor.c
>> +++ b/qdev-monitor.c
>> @@ -490,6 +490,11 @@ DeviceState *qdev_device_add(QemuOpts *opts)
        if (!oc) {
            qerror_report(QERR_INVALID_PARAMETER_VALUE, "driver", "device 
type");
            return NULL;
        }

        if (object_class_is_abstract(oc)) {
            qerror_report(QERR_INVALID_PARAMETER_VALUE, "driver",
                          "non-abstract device type");
            return NULL;
>>      }
>>  
>>      dc = DEVICE_CLASS(oc);
>> +    if (dc->cannot_instantiate_with_device_add_yet) {
>> +        qerror_report(QERR_INVALID_PARAMETER_VALUE, "driver",
>> +                      "pluggable device type");
>
> Is this a restoration of a previous state? Because I thought we
> shouldn't use QERR_* any more for new code...

See the additional context: I'm sticking to what the existing nearby
code does.

>> +        return NULL;
>> +    }
>>  
>>      /* find bus */
>>      path = qemu_opt_get(opts, "bus");
>>