[libvirt] [PATCH v2] qemu: map "virtio" video model to "virt" machtype correctly (arm/aarch64)

[Laszlo Ersek]

On 09/16/16 15:20, Pavel Hrdina wrote:
> On Fri, Sep 16, 2016 at 03:06:18PM +0200, Andrea Bolognani wrote:
>> On Fri, 2016-09-16 at 14:43 +0200, Pavel Hrdina wrote:
>>> On Fri, Sep 16, 2016 at 09:30:23AM +0200, Laszlo Ersek wrote:
>>>> Most of QEMU's PCI display device models, such as:
>>>  
>>> Pushed, thanks.
>>
>> Ouch, you were too fast! ;)
>>
>> There is something I wanted to clarify with Laszlo: is
>> virtio-gpu-pci ever going to be usable on other architectures
>> such as x86_64? Maybe it already is? Because if that's the
>> case, we'll want to be able to choose between virtio-vga and
>> virtio-gpu-pci.
>>
>> One solution would be to keep mapping model='virtio' to
>> virtio-vga and create a new model='virtio-gpu' that maps to
>> virtio-gpu-pci, then forbid aarch64 mach-virt guests to use
>> model='virtio'. Or something like that, I'm not married to
>> the idea, I just think it's something we should definitely
>> think about before this ends up in a release.
> 
> I have some patches in my TODO branch that will rewrite the video
> device code. virtio-gpu-pci is usable also on other architectures
> but it lacks the VGA compatibility mode.  In libvirt all primary
> video devices for x86 architecture have VGA mode.

Indeed, and that's a good thing. "virt" needs an exception because the
framebuffer is "exceptionally" broken on aarch64/KVM :)

> Currently we
> allow only QXL to be used as secondary video device

Yeah, I noticed that, and I was wondering if virtio-gpu-pci would
qualify at some point.

> and now with
> the virtio-gpu-pci it could be also used as secondary video device.
> 
> The solution would be simple, there is no need to add a new video
> model 'virtio-gpu', we will use the existing model 'virtio', but
> depending on architecture and also whether it's primary or
> secondary video device we will use appropriate device.

Sounds good to me (and the patch at hand should be compatible with the
idea). I'll have to read the rest of the thread to see if Andrea is okay
with the idea :)

Thanks!
Laszlo

> We already do this for QXL.
> 
> Pavel
>