Re: [Qemu-devel] Re: [PATCH] new SDL keyboard shortcuts to start and stop VM

[Anthony Liguori]

Avi Kivity wrote:
> On 10/26/2009 05:49 PM, Anthony Liguori wrote:
> > A user starts a VM at a physical box.  Everythings fine but he wants 
> > to return to his workstation so he closes the window.  He goes back 
> > to his workstation and connects to a VNC server (on a different X 
> > server).  He wants to now bring up the guest's display.
>
> Users don't have boxes.  They have computers.  They don't want to open 
> VNC clients and type in meaningless numerical addresses.  They do want 
> GUIs which fit with the OSes theme, cut'n'paste, printing, and shared 
> storage, all easily configurable.

You misunderstood.  The VNC session is to the users remote desktop.  But 
drop VNC for a minute, this is the same thing as just closing the window 
because the VM runs all day and you don't need to see it's display.  
Like I said, I've never been convinced that this is critical but it's 
always been a very vocal argument against more GUI functionality.

> > This cannot be achieved with a gui in the same process as qemu.  Is 
> > it necessary to support?  I don't know.
>
> In the priority list this is about 3000 places below having nice 
> buttons to eject and insert a CDROM.  A user with a "box" would 
> probably want to run the guest on a server (and use vnc, etc.).

I do agree with you.

> > I'd love to just replace the SDL display with GTK + Cairo.  I'm even 
> > somewhat inclined to suggest linking to python so that the gui can be 
> > written in python...
>
> Best would be to just export a QObject binding to scripting languages, 
> which could then be used to implement GUIs outside the qemu source 
> base.  The only tricky part is how to deal with the display.  Can we 
> expose the display as a special QDict?

I'd expose the display as a GTKWidget derivative.  We would load a 
python program and it could instantiate the widget because we've already 
loaded it.  I wouldn't bother with QObject at all.  Just setup an easy 
way to use QMP from within Python using the natural python types.

The trick only real trick is that the python script has to be launched 
from a separate thread because Python isn't asynchronous and has a big 
lock at the binding level.  But it works well if you have a socketpair 
with QMP that is used from the Python thread.

Regards,

Anthony Liguori