Share 1 GPU with multiple VMs?

[FlyingDoggy]

Hi, first time post here.

 

My limited research shows that it's very tricky to do so. I am asking since, with AMD Ryzen on the horizon (haha), I want to upgrade my machine and try virtualizing my PC, for example a gaming environment, a work environment, Linux, a bunch of other test environments etc. Obviously only the gaming environment will need a dedicated GPU passed through to it, the reset of them can share a less powerful GPU. As both Intel and AMD 8+ cores/threads products do not come with integrated GPU, and I don't really think a server board for Ryzen is coming out any time soon, the only choice seems to be sharing one GPU.

 

Is it as simple as plugging in 2 cards and use 1 to boot and pass through another one? If so, how can I decide which video output port belongs to which VM?

 

(and just out of curiosity, if I shutdown the VM that has the dedicated GPU, does the GPU get turned off?)

[METDeath]

AMD GPUs have no issue being the only GPU in the system and being passed through, that issue primarily affects Nvidia GPUs.

 

As for different VMs using the same GPU, that's fine as long as only one GPU is running. That said... some AMD GPUs have issues with power cycling where if the VM has to be force stopped the GPU may not come back online until unRAID gets rebooted.

[FlyingDoggy]

AMD GPUs have no issue being the only GPU in the system and being passed through, that issue primarily affects Nvidia GPUs.

 

As for different VMs using the same GPU, that's fine as long as only one GPU is running. That said... some AMD GPUs have issues with power cycling where if the VM has to be force stopped the GPU may not come back online until unRAID gets rebooted.

Please correct me if I'm wrong, but I thought there must be some sort of GPU (be it iGPU, on board VGA, or discrete graphics card) otherwise the system won't boot? In this case, an AMD Ryzen CPU doesn't have iGPU and I'd doubt any consumer motherboard will come with on board graphics, so my only choice would be installing another GPU. Which leads my other question: can I designate each port on that graphics card to output video signal of a specific VM? My guess is "no"?

[greg_gorrell]

You need a GPU in order to pass anything through.  I don't know if I am misunderstanding something here, but tons of motherboards come with onboard graphics.  There are even boards with APUs that combine CPU and GPU operations.  You are using AMD, you will only need one video card per VM, unless you plan on only using one at a time in which case you can just assign the card to whichever VM you want to use prior to starting in the VM manager.