Re: [Qemu-devel] [PATCH 1/2] hw: cannot_instantiate_with_device_add_yet due to pointer props

[Markus Armbruster]

Peter Maydell <address@hidden> writes:

> On 16 December 2013 08:48, Markus Armbruster <address@hidden> wrote:
>> Peter Maydell <address@hidden> writes:
>>> I kind of think this whole thing is backwards anyway:
>>> we should really say "the user can only instantiate
>>> devices via command line or monitor that are specifically
>>> intended to be hot-pluggable", rather than having an
>>> enormous list of devices we flag as not instantiable
>>> by the user. Even if someday we manage to make it technically
>>> possible to instantiate an omap_i2c device (say) from the
>>> command line, it will still be a completely bizarre thing to do
>>> because it's only intended to work as a part of the omap SoC.
>>
>> "Hot-pluggable" doesn't apply here.  There are plenty of devices that
>> can only be cold-plugged, yet are absolutely meant to be user-pluggable.
>> Real ISA cards, for instance.
>
> Mmm. Just plain "pluggable" would be more what I meant:
> modelling something that on real hardware is really a
> simple pluggable socket.

That makes sense to me.

>> However, the current code lets users plug absolutely everything, even
>> stuff that is known not to work.  The code still has the remnants of a
>> mechanism meant to protect users from known-not-to-work plugs, but it
>> got broken some time ago.  My "Clean up and fix no_user" series fixes
>> that regression in a way that's hopefully agreeable with Anthony, who
>> has been quite insistent on letting device_add plug more rather than
>> less.  This series merely patches some holes on top.
>>
>> The list of non-pluggable devices may be larger than the list of
>> pluggable ones, but: I count just 48 instances of
>> "cannot_instantiate_with_device_add_yet = true".  I doubt marking
>> devices that can be plugged instead of the ones than can't be would take
>> fewer marks.  Moreover, each one comes with a comment explaining *why*
>> the device cannot be plugged.  Sure nice to have when such a "why" goes
>> away.  Some of them are expected to go away eventually.
>
> I would expect 99% of actually pluggable devices to be pluggable
> because they're using a pluggable bus: ISA, PCI, USB, ...
>
> Anyway, I don't actively object to this series. I just think
> Anthony's going in the wrong direction which is why I haven't
> been particularly eager to actively mark it as reviewed-by me
> either...

Understandable :)

Thanks!