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

[Peter Maydell]

On 7 January 2013 19:32, Anthony Liguori <address@hidden> wrote:
> Christian Borntraeger <address@hidden> writes:
>
>> since
>>
>> commit 18b6dade8c0799c48f5c5e124b8c407cd5e22e96
>> qdev: refactor device creation to allow bus_info to be set only in class
>>
>> A user can specify a device that is no_user.
>> For example on my i386 box, I can add a 2nd kvmvapic device.
>>
>> This patch checks for no-user and rejects the device_add.
>>
>> Signed-off-by: Christian Borntraeger <address@hidden>
>
> I specifically broke this when QOM was introduced because no_user
> precludes a management tool from constructing a machine directlt.

You can't do that anyway...

> The real problem you're trying to solve is that it's an error to have
> two kvmvapic devices, not that users shouldn't be allowed to create them
> via -device.

That's not the only thing no-user gets used for. A bunch of the
ARM sysbus devices have it set presumably because it's just
flat impossible for a user to correctly create and wire in a sysbus
device at all, so you might as well not confuse matters by listing
them in '-device help' output. (We're not consistent about that,
though.)

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"...

-- PMM