Re: [Qemu-devel] -vga std vs. -device VGA

[Anthony Liguori]

On Thu, Nov 14, 2013 at 2:41 PM, Alexander Graf <address@hidden> wrote:
>
>
> Am 14.11.2013 um 17:32 schrieb Benjamin Herrenschmidt <address@hidden>:
>
>> On Thu, 2013-11-14 at 17:23 -0500, Alexander Graf wrote:
>>> Yes. But I think it's the correct thing to do in this case. X86 also
>>> doesn't create a USB controller like we would have to. Our pseries
>>> platform just doesn't have a legacy PC/AT keyboard controller.
>>
>> Sure, but that implies that -nodefaults -device VGA creates a working
>> usable machine on x86 and not on pseries...
>
> There is a set of devices that is always part of your machine. For the PC, 
> this is the PCI complex and SuperIO (including the keyboard controller).
>
> For pseries, we don't have that chip. We could simulate similar behavior 
> through a usb controller and keyboard. But those are devices that not every 
> pseries VM will want to have.
>
> So it really is libvirt's or the xml's job to add these.
>
> Even on x86 there are Atom chips out now that run without SuperIO, so we 
> might eventually have an x86 machine type without keyboard too, who knows.

As long as it's x86, there will always be a keyboard controller if you
ever want to support more than 1MB of RAM properly since the keyboard
controller is used to enable the a20 bit.

Regards,

Anthony Liguori

>
> Alex
>