Re: [Qemu-devel] [PATCH] qdev: obey no_user

[Anthony Liguori <aliguori@us.ibm.com>]

Andreas Färber <afaerber@suse.de> writes:

> Am 07.01.2013 23:20, schrieb Peter Maydell:
>> On 7 January 2013 22:10, Andreas Färber <afaerber@suse.de> wrote:
>>> Am 07.01.2013 21:16, schrieb Peter Maydell:
>>>> On 7 January 2013 20:12, Anthony Liguori <aliguori@us.ibm.com> wrote:
>>>>> Peter Maydell <peter.maydell@linaro.org> writes:
>>>>>> It seems to me like arbitrarily allowing the monitor to construct
>>>>>> no-user devices isn't really the right way to attack the problem
>>>>>> of "allow complete machine construction by management tools"...
>>>>>
>>>>> There is no such thing as a 'no-user' device.  It's a silly distinction
>>>>> that has never had a consistent meaning.
>>>>
>>>> Then let's just rip that flag out completely.
>>>
>>> That's a bad idea, given that we are about to make the CPU a device.
>> 
>> We already have a pile of devices which the user can't usefully
>> use -device on...CPUs would be just another one, right?
>
> Not sure what you're arguing for here? The CPU is the worst example of a
> device I know in that it is not limited to a particular bus and messes
> with global state and threads.
>
> Also, I'm sure that there will be objects/devices that a management tool
> is not supposed to mess with either, once we start using
> object_initialize() more.
>
> If we agree that "no_user = 1" is not ideal or used inconsistently, then
> we should IMO talk about how to replace/amend it and not conclude to
> just rip it out and leave users without sensible error messages while
> praying for The Omnipotent Management Tool that AFAICS we don't have
> today...

If you want to replace 'no_user' with
'cannot_instantiate_with_device_add_yet_due_to_internal_bugs' I'm okay
with that.

I'm all for having friendly errors for users.  But no_user doesn't just
serve a 'broken' flag today.  Random devices are marked as no_user that
really shouldn't be like isa-fdc.

Regards,

Anthony Liguori

>
> Andreas
>
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