Re: [Qemu-devel] [PATCH] Experimental initial patch providing accelerated OpenGL for Linux i386 (2nd attempt to post)

[Fabrice Bellard]

Hi,

I find your patch interesting and I'll try to include it in QEMU ASAP.

My main remark is that the host/guest communication system must be 
changed and I can help you to implement it. I would prefer to use a PCI 
device and to avoid any i386 dependent code. For the PCI device, using 
the Bochs VGA adapter could be a possible idea. All the parameters and 
data should be transmitted as if the PCI device was doing DMA. A single 
I/O port could be used to start executing a list of OpenGL commands.

Once a basic Linux target OpenGL library is OK, it would be good to work 
on the equivalent Windows guest code by reusing the wine D3D code...

Regards,

Fabrice.

Even Rouault wrote:
> Here's an attempt of providing accelerated OpenGL for QEMU.
> I must underline first that it should really really be considered as 
> experimental or a proof-of-concept. There's
> still a lot of work to do to make it reliable and releasable.
> So what is it exactly ?
> - a patch for QEMU itself that intercepts any call to 'int $0x99' which is the 
> interface I have chosen to dedicate to
>   communication between guest user programs and QEMU. The modification of QEMU 
> existing code is very slight.
>   The essential of code on the guest side is in new files.
> - a replacement libGL.so library that must be used inside the Linux guest. The 
> library redirects guest OpenGL and GLX calls
>   to host side, where your host libGL.so will do the real job.
>
> It works currently only with Linux x86 as guest and host OS.
>
> Now, the good news : which programs do currently work with this patch ?
> - glxinfo
> - glxgears. I get ~330 FPS with QEMU/GL (direct GLX), ~210 FPS through a SSH 
> console on the guest OS (indirect GLX)
> - some mesa demos programs.
>     * tunnel     : ~26 FPS with QEMU/GL,  ~3 FPS through a SSH console on the 
> guest OS
>     * teapot     : ~50 FPS with QEMU/GL,  ~7 FPS through a SSH console on the 
> guest OS
>     * fire       : ~14 FPS with QEMU/GL,  ~2 FPS through a SSH console on the 
> guest OS
>     * arbfplight : ~100 FPS with QEMU/GL,  not possible through a SSH console 
> on the guest OS (GL_ARB_vertex_program not available)
> - ... and ppracer ! (some crash from time to time. Starting at ~20 FPS at the 
> beginning of the race, and finishing at ~10 FPS... strange...)
>
> How fast is it ? Enough fast to have 15 FPS in ppracer with KQEMU disabled.
> When KQEMU is enabled, paradoxically, the performance is really poor :-(
>
> Successfully tested on the following platforms :
> - Ubuntu Edgy x86 as host with ATI FGLRX driver / FC5 x86 as guest
> - Ubuntu Dapper x86 as host with NVIDIA Proprietary driver / Ubuntu Dapper x86 
> as guest
>
> Which programs do not work : probably most for the moment ;-)
> I'd like to make it work with XGL (I've downloaded the latest Mandriva 2007 
> Live CD and I'm quite
> impatient to enable the 3D in it) and GoogleEarth.
>
> How to use it ? (ONLY on Linux i386 and with only i386-softmmu as target-list)
> * Apply the patch and recompile QEMU 
> * Lauch QEMU with -enable-gl option
> * Get the compiled libGL.so from ./i386-softmmu and copy it to the guest OS
> * In the guest OS : LD_LIBRARY_PATH=/path/to/replacement/libGL.so glxgears
>
> TODO list :
> - implement correctly full OpenGL API
> - improve vertex arrays support
> - maybe fix how the end of the guest process is detected
> - make replacement libGL work when compiled with optimization flags
> - integrate in a better way the window that popups on the guest side with the 
> main qemu window
> - integrate it properly into QEMU build system (helper_opengl.c can't compile 
> with -O2 : 'unable to find a register to spill in class `DIREG'')
> - understand why it's slower when KQEMU enabled and try to fix that if 
> possible
> - enable several guest OS processes to use OpenGL at the same time
> - make it run on x86_64, and allowing any combination guest x86/x86_64 and 
> host x86/x86_64, other archs
> - port it to other UNIX-like OS with X
> - improve security if possible (preventing malicious guest code from crashing 
> host qemu)
> - clean the code !
> - much testing and debugging
> - port it to Windows platform (first OpenGL / WGL, then D3D through Wine 
> libs ?)
> - make a patch to Valgrind to make it happy with 'int $0x99' when running on 
> guest side
> - ...
>
> The new files :
> - opengl_client.c  : the OpenGL guest library
> - helper_opengl.c : main guest-side code
> - gl_func.h, server_stub.c, client_stub.c : generated files by parse_gl_h.c 
> from gl.h parsing
> - glgetv_cst.h  : generated file from parsing of a man page
> - gl_func_perso.h, opengl_func.h : hand-written "prototypes"
>
> In the mean time, enjoy !
>
> PS :
> I posted a similar message thursday, but it didn't get to the list apparently, 
> maybe because of the two big attached patch (500 kB). I have reduced the size 
> of the patch to 160 KB by not including generated source files. I will send 
> it just after, so this message has a chance of coming. If you don't see a 
> following message with the patch attached, I'll have to figure out where to 
> store the patch...
>
>
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