CUDA and NVIDIA emulation

[KevinKK]

Will it ever be possible to emulate an NVIDIA grahpics card?
i understand that it is very difficult to emulate CUDA and maybe PhysX but could it be possible that this is directly forwarded to the host GPU (if it´s nvidia of course) and only the NVIDIA device is emulated?


and it would be a great development for people who are programming on linux and the software should be for windows too. they always have to reboot their system to develop in windows. if they could do the in a VM that would be great!

I know that what i want is very difficult^^ but is it an aim to achieve something like that or a development in that direction?

[Sasquatch]

You're failing to see the difficulty in writing a virtual video card. You need darn good documentation and nVidia is a company that makes money with their video cards. The specifications and how to 'emulate' it isn't going to appear any time soon for the broad public. Since VB is open source, the video documentation needs to be freely available. Just not going to happen.

[KevinKK]

well i thought so.. and not even CUDA forwarding instead of emulation will be possible?

[Sasquatch]

There have been topics about sending a video card to the Guest directly, but it's all theory for now. I think that before I am at an age to retire, this will be available. And I have a long time to go before I have to/can retire .

[KevinKK]

that´s a bit of hope^^ then it´s probably before i´ll have my pension xD
how is the game development now? is it an aim to support a good gaming in the VM?
you can play Tomb Raider Anniversary in the VM but it has some graphic bugs^^
Wine doesn´t work correct on my system.. only some "small" games are running but this games i could also run in the VM with the same speed..
things like Cossacks or Stronghol Crusader..

[Sasquatch]

Games that are 5 years old might barely run in a VM. I know that F.E.A.R. for example will not run in a VM, it's too demanding. But games like Red Alert 3 would. C&C3 on the other hand won't or with all settings low to very low. Anyway, if you want to play a game in a VM, check the requirements and if it's not too high, try it.

[KevinKK]

yes of course.. you didn´t tell me something new here.
my question was about the general aim to provide a better gaming performance in a VM and whether something is already in the development of that direction.

[Sasquatch]

Well, research is done in how to accomplish this with VT-d. Maybe the hardware and Host OS need to support it, as you're essentially yanking a piece of hardware out of the system and plug it in another. Who knows what the OS does when you remove the video card, assuming the system stays running. But it's not top priority, so it will take some time.

[mpack]

As you say, virtualising an existing proprietary advanced graphics card (NVidia, Radeon et al) is probably doomed by a lack of open documentation - and anyway a lot of work for a card that will likely be quickly obsolete. More promising IMHO would be to design your own virtual card with similar capabilities, whose design you can control and keep up to date. There needs to be an underlying translation layer to map calls onto host capabilities... this sounds close to what has already been started.

[darkmikey]

I just thought I'd add a thought I had the other day. Would it be possible to have two gpus installed, as in SLI/Crossfire configurations, and then give the guest os direct access to just one of them, whilst forcing the host os to only use the other, perhaps by tricking it into thinking that its driving a second monitor or something. I assume that the developers have already toyed with such ideas, and found them in-viable, but on the off chance they hadn't . I guess it would be a lot easier if the manufacturers implemented a VT-x like technology for their graphics cards.

[Sasquatch]

A VT-x like implementation isn't going to do the trick, because VT-x is nothing more than a bug fix in the x86 architecture. It wasn't designed to provide virtualisation. That was apparent when they first started to virtualise things, back in the '80s. The processors back then weren't x86, but perfectly capable of virtualising things. Only now, with VT-x (and AMD-V), it's possible to get better performance out of the x86 CPU architecture. Until this feature was available, virtualisation generated a lot of overhead (compared to the processors back in the '80s that didn't have this bug).