Re: [Qemu-devel] [PATCH] hw/s390x/sclp: Mark the sclp device with user_creatable = false

[Thomas Huth <thuth@redhat.com>]

On 04.10.2017 17:18, Pierre Morel wrote:
> On 04/10/2017 15:53, Thomas Huth wrote:
>> The "sclp" device is just an internal device that can not be instantiated
>> by the users. If they try to use it, they only get a simple error
>> message:
>>
>> $ qemu-system-s390x -nographic -device sclp
>> qemu-system-s390x: Option '-device s390-sclp-event-facility' cannot be
>> handled by this machine
>>
>> Since sclp_init() tries to create a TYPE_SCLP_EVENT_FACILITY which is
>> a non-pluggable sysbus device, there is really no way that the "sclp"
>> device can be used by the user, so let's set the user_creatable = false
>> accordingly.
>>
>> Signed-off-by: Thomas Huth <thuth@redhat.com>
>> ---
>>   hw/s390x/sclp.c | 5 +++++
>>   1 file changed, 5 insertions(+)
>>
>> diff --git a/hw/s390x/sclp.c b/hw/s390x/sclp.c
>> index 30aefbf..9be0cb8 100644
>> --- a/hw/s390x/sclp.c
>> +++ b/hw/s390x/sclp.c
>> @@ -606,6 +606,11 @@ static void sclp_class_init(ObjectClass *oc, void
>> *data)
>>       dc->realize = sclp_realize;
>>       dc->hotpluggable = false;
>>       set_bit(DEVICE_CATEGORY_MISC, dc->categories);
>> +    /*
>> +     * Reason: Creates TYPE_SCLP_EVENT_FACILITY in sclp_init
>> +     * which is a non-pluggable sysbus device
>> +     */
>> +    dc->user_creatable = false;
>>
>>       sc->read_SCP_info = read_SCP_info;
>>       sc->read_storage_element0_info = read_storage_element0_info;
>>
> 
> I must miss something.
> Why is the sclp device not a SYS_BUS_DEVICE ?
> The problem seems to come from the heterogeneity of the sclp and sclp
> generated devices.

I wonder whether it should rather be the other way round: Why is
TYPE_SCLP_EVENT_FACILITY a sysbus device? Sysbus is an abstraction for
simple on-board devices, while TYPE_SCLP_EVENT_FACILITY seems rather to
be a pseudo-device... so it should rather simply be of TYPE_DEVICE
instead? Or do I miss something?

 Thomas