[Qemu-devel] QEMU without X11 support

[Qemu-devel] QEMU without X11 support

[hanji unit]

Hello, is it possible to run (or rebuild modifying build flags) QEMU
without support for X11 window system integration? I keep seeing XSync
in libX11 being called, so i know QEMU is trying to talk to X. I am
running QEMU using Xvfb since I still need the SDL rendering to work.
Here is how i am running QEMU from a script:

export DISPLAY=:1
Xvfb :1 -screen 0 1024x768x16 &


Thanks.

Re: [Qemu-devel] QEMU without X11 support

[Gerd Hoffmann]

On Thu, 2017-10-12 at 16:25 -0400, hanji unit wrote:
> Hello, is it possible to run (or rebuild modifying build flags) QEMU
> without support for X11 window system integration?

./configure --disable-gtk --disable-sdl --disable-opengl

cheers,
  Gerd

Re: [Qemu-devel] QEMU without X11 support

[Peter Maydell]

On 13 October 2017 at 08:00, Gerd Hoffmann <kraxel@redhat.com> wrote:
> On Thu, 2017-10-12 at 16:25 -0400, hanji unit wrote:
>> Hello, is it possible to run (or rebuild modifying build flags) QEMU
>> without support for X11 window system integration?
>
> ./configure --disable-gtk --disable-sdl --disable-opengl

You can also use the runtime -display options (assuming
your development environment has the libraries
and your runtime environment has them installed, there's
no harm in having a QEMU that was built with gtk support
and not using the gtk UI.)

There are a couple of parts to this:
 (1) does your guest OS require a graphics device?
(eg typically Windows does, ARM Linux will happily use
a serial port)
 (2) if you do need a graphics device, where does the
output go?
(eg you can tell QEMU to just not show graphics at
all with -display none, use -display vnc to for a VNC
server, etc. Some of the -display options will use
X11, and some won't.)
 (3) do you want to specifically avoid any dynamic
library dependency between QEMU and the X11 libs,
or do you just not want to have to use X11 to
display?
(see above about compiling out if necessary)

thanks
-- PMM

Re: [Qemu-devel] QEMU without X11 support

[Philippe Mathieu-Daudé]

>> Hello, is it possible to run (or rebuild modifying build flags) QEMU
>> without support for X11 window system integration?
> 
> ./configure --disable-gtk --disable-sdl --disable-opengl

Is there some interest in adding a simpler --disable-x11 option?

Re: [Qemu-devel] QEMU without X11 support

[Peter Maydell]

On 14 October 2017 at 17:38, Philippe Mathieu-Daudé <f4bug@amsat.org> wrote:
>>> Hello, is it possible to run (or rebuild modifying build flags) QEMU
>>> without support for X11 window system integration?
>>
>> ./configure --disable-gtk --disable-sdl --disable-opengl
>
> Is there some interest in adding a simpler --disable-x11 option?

We don't directly link to X11, so it wouldn't fit with
our other options.
The --disable-foo options aren't very often necessary --
only if your build environment has support for linking
against foo but for some reason you don't want it
linked in.

thanks
-- PMM

Re: [Qemu-devel] QEMU without X11 support

[Michal Suchánek]

On Fri, 13 Oct 2017 17:08:49 +0100
Peter Maydell <peter.maydell@linaro.org> wrote:

> On 13 October 2017 at 08:00, Gerd Hoffmann <kraxel@redhat.com> wrote:
> > On Thu, 2017-10-12 at 16:25 -0400, hanji unit wrote:  
> >> Hello, is it possible to run (or rebuild modifying build flags)
> >> QEMU without support for X11 window system integration?  
> >
> > ./configure --disable-gtk --disable-sdl --disable-opengl  
> 
> You can also use the runtime -display options (assuming
> your development environment has the libraries
> and your runtime environment has them installed, there's
> no harm in having a QEMU that was built with gtk support
> and not using the gtk UI.)
> 
> There are a couple of parts to this:
>  (1) does your guest OS require a graphics device?
> (eg typically Windows does, ARM Linux will happily use
> a serial port)
>  (2) if you do need a graphics device, where does the
> output go?
> (eg you can tell QEMU to just not show graphics at
> all with -display none, use -display vnc to for a VNC
> server, etc. Some of the -display options will use
> X11, and some won't.)

iirc you also need to specify -nographic so qemu does not try to use the
X11 GUI to display your serial output.

HTH

Michal

Re: [Qemu-devel] QEMU without X11 support

[Paolo Bonzini]

On 15/10/2017 16:01, Michal Suchánek wrote:
>>> ./configure --disable-gtk --disable-sdl --disable-opengl  
>> You can also use the runtime -display options (assuming
>> your development environment has the libraries
>> and your runtime environment has them installed, there's
>> no harm in having a QEMU that was built with gtk support
>> and not using the gtk UI.)
>>
>> There are a couple of parts to this:
>>  (1) does your guest OS require a graphics device?
>> (eg typically Windows does, ARM Linux will happily use
>> a serial port)
>>  (2) if you do need a graphics device, where does the
>> output go?
>> (eg you can tell QEMU to just not show graphics at
>> all with -display none, use -display vnc to for a VNC
>> server, etc. Some of the -display options will use
>> X11, and some won't.)
> iirc you also need to specify -nographic so qemu does not try to use the
> X11 GUI to display your serial output.

Right.  -nographic's effects can be described in terms of other
command-line options, but it is pretty hairy.  The effects fall in two
categories:

1) -nographic is a shortcut for "-display none -machine graphics=off"

2) it changes the default character device backend from "vc:80Cx24C"
(80x24 graphical console) to either "mon:stdio" or "stdio", except for
the parallel port whose default becomes simply "null".

Paolo