Re: KVM usability

Anthony Liguori
2010-03-01T15:36:10Z

On 03/01/2010 03:25 AM, Ingo Molnar wrote:
> * Zachary Amsden<zamsden@redhat.com> wrote:
>
>
>>> Here's my experience with it:
>>>
>>> - qemu-kvm starts up with a miniature resolution by default. 640x480 - on my
>>> 1680x1050 laptop screen. It's so small that initially i even overlooked
>>> that i started it. It should multiplex pixels up to a reasonable screen
>>> size by default.
>>>
>> No virtualization emulator today does this, it is not a reasonable thing to
>> do. Unless you are running compiz and use hardware scaling. We should look
>> into it.
>>
> I tried VirtualBox and it does something sane here: while it does not give a
> larger guest screen area, it at least creates a large enough X window, with
> any border area whited out.
>
> That looks far more pleasing aesthetically than the Qemu method of resizing
> the full window wildly. The guest still resizes, but it stays within the same
> X window and the border is white.
>
> Also, with Windows guests, the Windows side resolution resizes dynamically if
> the window is grown/shrunk by the user. (I suspect that is done via a paravirt
> driver on the guest side, through 'Guest Additions'.)
>

We have to core pieces to do this in qemu. The vmware vga driver
supports this and it just takes a small userspace program to resize the
VGA on demand.

The problem is, you need a way to communicate from the host to the
guest's userspace. We did not have a mechanism until very recently
(virtio-serial) because we've encountered a ton of resistance within the
kernel community for the things we've proposed.

VirtualBox gets around this by just shipping their own Linux drivers.

Regards,

Anthony Liguori

> Ingo
>