[vbox-dev] D3D support in custom frontend

Rūdolfs Bundulis rudolfs.bundulis at gmail.com
Tue Feb 10 14:33:58 GMT 2015


I also wanted to ask are there any known release dates for the next version
where the GUI processes will be separated and won't face the hardening
issues? I've seen bugs regarding crashes with multiple CPUs (like
https://www.virtualbox.org/ticket/13319 ) being solved in 4.3.20 so I
wanted to know if a release of that codebase without the hardening is
planned in foreseeable future, that could also address the crashes I'm
having. Just a general inquiry.

Best Regards,
Rudolfs Bundulis

2015-02-09 12:54 GMT+02:00 Rūdolfs Bundulis <rudolfs.bundulis at gmail.com>:

> Hi Klaus,
> thanks for the response, yeah I suspected that the path was read from
> somewhere, since running regsvr32 to unregister VBoxC.dll from installation
> directory and then registering it from my path didn't chagne anything, but
> I'm happy - it's not an issue to run my binaries from the installation
> folder, the main thing is that things seem to be working. Now the only
> thing I need is to see if I can make OpenGL render to a custom FBO so I can
> live without the window and access the OpenGL pixel data, but that is my
> issue, if I come up with anything interesting maybe that can be use fro you
> too. At least as far as I understand right now, due to the need of a window
> on the host, VBoxHeadless.exe does not provide any 3D acceleration support
> right?
> Sorry to bother you so much, but the issue I'm more troubled by is the
> crash I get - I've already described it before but I have made little
> progress. Basically what happens is whenever I start my VM with my custom
> frontend with more than 1 CPU it crashes on Windows startup
> (longjmp_internal from Microsoft C runtime fails with unaligned stack, the
> last stack entry I saw from VBoxREM.dll was cpu_exit_loop or smth) - since
> VBoxREM.dll is built with MinGW visual studio does not help a lot, and when
> running under debug version under MinGW I also was unable to obtain any
> valuable info. With 1 CPU it always works fine. I've tried CRT debug heap,
> Application Verifier etc. to find potential issues with my code (since the
> default Qt frontend does not crash with the same configuration) I blame my
> part of the code, but still maybe there are some peculiarities with the COM
> interface. Do you know any bugs that have reported similar issues to what
> I'm seeing? Or maybe you can give any pointers since currently I'm kind of
> stuck.
> Again, great thanks for the support, my research would have hit dead end
> without your help, yesterday I finally finished splitting so thanks to
> VirtualBox I am able to run a single virtual 9600x5400 display on
> VirtualBox (what is weird, even with WDDM drivers) and split/encode it to
> 25 displays, basically this cannot be done with hardware (well in terms of
> a single homogeneous display) so I'm very happy.
> Best Regards,
> Rudolfs Bundulis
> 2015-02-09 12:21 GMT+02:00 Klaus Espenlaub <klaus.espenlaub at oracle.com>:
>>  Rūdolfs,
>> 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
>> stuff.
>> 2015-02-07 18:37 GMT+02:00 Rūdolfs Bundulis <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.
>> Klaus
>>> 2015-01-26 15:25 GMT+02:00 Rūdolfs Bundulis <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>:
>>>>>  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> 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>:
>>>>>>  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> 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>
>>>>>> :
>>>>>>>  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> 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
>>>>>>> >:
>>>>>>>> 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> 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
>>>>>>>>  > _______________________________________________
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>>>>>>>> > vbox-dev at virtualbox.org
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