[vbox-dev] D3D support in custom frontend

Klaus Espenlaub klaus.espenlaub at oracle.com
Mon Feb 9 10:21:44 GMT 2015


On 09.02.2015 10:28, Rūdolfs Bundulis wrote:
> Hi,
> yeah it turned out that when running from the VirtualBox installation 
> path 3D support works for my frontend, seems that it comes from the 
> fact that the COM API is using the dll's  from the installation 
> folder. I'm just gonna leave this information here in case anyone else 
> stumbles on the same issue.
VBoxC.dll contains "in-process" COM components (which live in the "API 
client" process), and the path to it is kept in the registry. Normal COM 
> 2015-02-07 18:37 GMT+02:00 Rūdolfs Bundulis 
> <rudolfs.bundulis at gmail.com <mailto:rudolfs.bundulis at gmail.com>>:
>     Hi,
>     again thanks for all the previous help, I managed to build VBox
>     with the LogRel() but when I copied the dll's over the
>     installation i got a ton of errors about invalid image hashes (I
>     guess that just copying over is not the way to go). Anyhow, I came
>     up with a different approach and made a small frontend that would
>     basically do the same stuff as my app but also draw the output to
>     a window. When I launch the application from the VirtualBox
>     installation folder everything works fine - 3D support works, when
>     I take the app and all the virtualbox binaries and put them in a
>     random folder, it again stops working. And what is interresting
>     that using Process Explorer I was able to see that actually two
>     copies of VBoxC.dll are loaded (one from the installation folder
>     and one from my folder) and one VBoxRT.dll (only from the
>     VirtualBox installation folder). I assume the ones from the
>     installation folder are loaded by the COM object? Is this a very
>     very bad practice to try and deploy the VirtualBox binaries
>     outside the installation path?
The invalid image hashes most likely mean that VirtualBox isn't 
accepting the signature in your binaries. It only accepts the "one 
signer" of everything, so if you mix Oracle and your own build then it 
won't work very well.

Deploying VirtualBox binaries outside the installation path isn't 
exactly forbidden, but we don't test it right now. This will stay for a 
while, we have still way too much noise on the hardening related tickets.

>     2015-01-26 15:25 GMT+02:00 Rūdolfs Bundulis
>     <rudolfs.bundulis at gmail.com <mailto:rudolfs.bundulis at gmail.com>>:
>         Hi Vitali,
>         this was what I was looking for, much appreciated :)
>         Best Regards,
>         Rudolfs Bundulis
>         2015-01-26 14:59 GMT+02:00 Vadim Galitsyn
>         <vadim.galitsyn at oracle.com <mailto:vadim.galitsyn at oracle.com>>:
>             Hi Rudolfs,
>             you could add LogRel() messages and they should appear in
>             release log (VBox.log file) once VBox has been built w/
>             corresponding flag. Note, that this only works for guest
>             R0 code (miniport). Adding LogRel() to R3 code (display
>             driver) will not result in extra messages in log.
>             Please consider to add VBOX_WITH_R0_LOGGING=1 into
>             LocalConfig.kmk in order to enable LogRel()’s.
>             Vadim
>>             On 26 Jan 2015, at 15:26, Rūdolfs Bundulis
>>             <rudolfs.bundulis at gmail.com
>>             <mailto:rudolfs.bundulis at gmail.com>> wrote:
>>             Hi Vadim,
>>             ok clear, thanks for the info. We'll so far I haven't
>>             patched anything in the VBox code itself, as I said I
>>             have a custom frontend. Does that code help you in any
>>             way? I'll make a debug build and look for more messages
>>             and mail back if it gives any additional info, thanks for
>>             all the help so far. The main thing I wanted to
>>             understand was is there any way to see the output from
>>             the WARN macros in the miniport driver, and as far as I
>>             understand there is none.
>>             Best Regards,
>>             Rudolfs Bundulis
>>             2015-01-26 13:42 GMT+02:00 Vadim Galitsyn
>>             <vadim.galitsyn at oracle.com
>>             <mailto:vadim.galitsyn at oracle.com>>:
>>                 Hi Rudolfs,
>>                 Debug build of VBox itself would probably add a bit
>>                 more messages to VBox.log (and to debug log as well),
>>                 but this definitely will not prevent the fact that
>>                 debug version of GAs cause BSOD. Is it possible if
>>                 you share a patch to OSE tree with your changes, so I
>>                 could take a look at it later this week (or another)?
>>                 Vadim
>>>                 On 26 Jan 2015, at 14:00, Rūdolfs Bundulis
>>>                 <rudolfs.bundulis at gmail.com
>>>                 <mailto:rudolfs.bundulis at gmail.com>> wrote:
>>>                 Hi Vadim,
>>>                 Well since I also came to the the conclusion that
>>>                 the WinId could cause this, I tried making a dummy
>>>                 window for each of the IFramebuffer instances, but
>>>                 nothing changed. Though the windows do not have any
>>>                 logic in the message loop, and I do not resize them
>>>                 when the resolutions change - maybe this causes some
>>>                 errors. That is why I asked if any logs from the
>>>                 miniport driver is available to see where does it
>>>                 actually crash. If I make a debug VirtualBox build
>>>                 then would debug GAs work?
>>>                 Best Regards,
>>>                 Rudolfs Bundulis
>>>                 2015-01-26 12:50 GMT+02:00 Vadim Galitsyn
>>>                 <vadim.galitsyn at oracle.com
>>>                 <mailto:vadim.galitsyn at oracle.com>>:
>>>                     Hi Rudolfs,
>>>                     As far as I can understand, returning NULL WinID
>>>                     might cause the behaviour you are observing on
>>>                     Windows host (please note, I have not tried that
>>>                     locally, take it like a gesture). Seems, you
>>>                     also already have 3D host service running. Can
>>>                     you try to provide valid WinID to
>>>                     Main/src-client stuff as an experiment and see
>>>                     if things changed?
>>>                     Regarding to GAs, I am afraid you’ll have a BSOD
>>>                     in guest once you attempt to boot VM with debug
>>>                     GAs installed. We currently have some debug R0
>>>                     assertion there.
>>>                     Vadim
>>>>                     On 26 Jan 2015, at 13:12, Rūdolfs Bundulis
>>>>                     <rudolfs.bundulis at gmail.com
>>>>                     <mailto:rudolfs.bundulis at gmail.com>> wrote:
>>>>                     Hi Vadim,
>>>>                     thanks for the pointers, I'll look up the code,
>>>>                     I was already afraid that something is simply
>>>>                     missing.
>>>>                     To describe what I am doing:
>>>>                     I am running a research project in University
>>>>                     of Latvia where we are trying to use VirtualBox
>>>>                     for large scale high resolution display wall
>>>>                     construction - basically we run VirtualBox with
>>>>                     a custom frontend that takes the video data
>>>>                     from the VRAM, encodes it and streams over to a
>>>>                     display wall, currently we've been able to run
>>>>                     a 9600x5400 surface with Windows XPDM (we set
>>>>                     this resolution as a hint and then internally
>>>>                     split it to  5*5 1920x1080 displays) , which is
>>>>                     really impressive, so thanks again for the
>>>>                     great software. In terms of resolution I guess
>>>>                     this is as far as the existing 256MB VRAM limit
>>>>                     in VirtualBox can go (at least according to the
>>>>                     calculations for framebuffer needs provided by
>>>>                     Klaus Erspenlaub and mentioned in your code).
>>>>                     Since the resolution limit is reached we are
>>>>                     trying to address two more issues - 3D support
>>>>                     and a weird unaligned stack crash in
>>>>                     VBoxREM.dll with more than 1 CPU shared to the
>>>>                     machine (for the second issue I need to do some
>>>>                     more research as to where it is coming from
>>>>                     before I ask any help here). As for the 3D -
>>>>                     we'd basically want our software to function in
>>>>                     the same way the VirtualBox QT client does, but
>>>>                     currently it does not. Thanks for the pointer
>>>>                     about the HGCM/OpenGL service, I'll check out
>>>>                     that code and see what I can adapt.
>>>>                     Our software basically uses the VirtualBox COM
>>>>                     interface to create the needed machine, set the
>>>>                     number of displays/resolutions, injects the
>>>>                     IFramebuffer instances and powers up the
>>>>                     machine via the IConsole interface. So I
>>>>                     examined all the IFramebuffer implementations
>>>>                     in VirtualBox frontends, and didn't see
>>>>                     anything very special in the 3D related
>>>>                     callbacks there. As for the log - I tried to
>>>>                     compare the log of a session from our software
>>>>                     with a session from the same machine under QT
>>>>                     fronted where the 3D acceleration works.
>>>>                     Basically there were no errors and differences,
>>>>                     in both cases the logs contained the lines
>>>>                     about OpenGL support (i guess this comes from
>>>>                     the OpenGL capability test exe), I'll send both
>>>>                     logs as soon as I get back to that machine but
>>>>                     I doubt they'll give much help, since they
>>>>                     don't have any errors, and in both of them the
>>>>                     guest additions log line states that
>>>>                     acceleration is supported. Basically the only
>>>>                     thing that differs is that the D3D/OpenGL
>>>>                     (we've tried both API's, since the test
>>>>                     application is built on Unity it is trivial to
>>>>                     force either mode) device creation fails on our
>>>>                     frontend. That is why I asked about the
>>>>                     get_WinId, I examined the miniport driver code
>>>>                     and as far as I understood it uses the window
>>>>                     id value to create a swap chain. Out frontend
>>>>                     does not have an actual window, so I am always
>>>>                     returning NULL, can this cause an error? I also
>>>>                     saw that the miniport driver has a lot of WARN
>>>>                     macros, is  the output visible anywhere? I
>>>>                     tried using DebugView but that didn't help?
>>>>                     Should I try building a debug version of guest
>>>>                     additions to get some log information?
>>>>                     Best Regards,
>>>>                     Rudolfs Bundulis
>>>>                     2015-01-26 10:34 GMT+02:00 Vadim Galitsyn
>>>>                     <vadim.galitsyn at oracle.com
>>>>                     <mailto:vadim.galitsyn at oracle.com>>:
>>>>                         Hi Rudolfs,
>>>>                         In order to provide 3D acceleration, VBox
>>>>                         HGCM/OpenGL host service should be running.
>>>>                         It is currently a part of VirtualBoxVM
>>>>                         process (ShCrOpenGL thread). In order to
>>>>                         provide 3D acceleration support for your
>>>>                         frontend, I am afraid, you need to adapt
>>>>                         stuff from this thread for your code. And I
>>>>                         am afraid this might be not that easy
>>>>                         (there is a bit of magic when VBox GUI
>>>>                         conversates w/ 3D stuff). Please refer to
>>>>                         src/VBox/HostServices/SharedOpenGL and
>>>>                         src/VBox/GuestHost/OpenGL sources.
>>>>                         Btw, if you describe a little bit more why
>>>>                         do you need this and what you already have
>>>>                         done, maybe I could explain you more
>>>>                         things/steps you need to do in order to
>>>>                         reach the goal. VBox.log also might be helpful.
>>>>                         Vadim
>>>>                         > On 24 Jan 2015, at 14:14, Rūdolfs
>>>>                         Bundulis <rudolfs.bundulis at gmail.com
>>>>                         <mailto:rudolfs.bundulis at gmail.com>> wrote:
>>>>                         >
>>>>                         > Hi,
>>>>                         >
>>>>                         > I'm having a bit of a hard time
>>>>                         understanding why my custom framebuffer
>>>>                         cannot use the 3D acceleration feature. I
>>>>                         have a Windows 7 guest machine (3D
>>>>                         acceleration enabled, guest additions
>>>>                         installed) and a Unity demo application.
>>>>                         Under the default QT GUI the application
>>>>                         launches fine, while under my frontend
>>>>                         Unity is not able to create the D3D device.
>>>>                         First I though that this could be due to
>>>>                         incorrect implementation of IFramebuffer,
>>>>                         but when I looked at
>>>>                         UIFrameBuffer::Notify3DEvent(ULONG uType,
>>>>                         BYTE *pData) in UIFrameBuffer.cpp there
>>>>                         wasn't any special magic there. Are there
>>>>                         any hints to guide me towards understanding
>>>>                         the cause of this? Is there any tracing
>>>>                         facilities for the guest miniport driver?
>>>>                         Also, I don't have a window handle for my
>>>>                         frontend since there is no actual window.
>>>>                         If I am returning 0 in get_WinId in my
>>>>                         framebuffer can that mess things up?
>>>>                         >
>>>>                         > Best Regards,
>>>>                         > Rudolfs Bundulis
>>>>                         >
>>>>                         _______________________________________________
>>>>                         > vbox-dev mailing list
>>>>                         > vbox-dev at virtualbox.org
>>>>                         <mailto:vbox-dev at virtualbox.org>
>>>>                         >
>>>>                         https://www.virtualbox.org/mailman/listinfo/vbox-dev
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