RTX2080 vfio pasthrough surprise

billington.mark · January 16, 2019, 8:34pm

So,

I received an RTX2080 today (took advantage of the EVGA step up programme as I got a 1080 in July).

This is what hardware it presents:

IOMMU group 20:
[10de:1e87] 03:00.0 VGA compatible controller: NVIDIA Corporation TU104 [GeForce RTX 2080 Rev. A] (rev a1)
[10de:10f8] 03:00.1 Audio device: NVIDIA Corporation Device 10f8 (rev a1)
[10de:1ad8] 03:00.2 USB controller: NVIDIA Corporation Device 1ad8 (rev a1)
[10de:1ad9] 03:00.3 Serial bus controller [0c80]: NVIDIA Corporation Device 1ad9 (rev a1)

So… Previous Nvidia cards I’ve had presented as 2 devices. One graphics device and one audio device. The ‘new’ extra two are the serial bus (which I assume is the RGB controller), and a usb controller.

To my surprise, the usb type-c port on the back of the card actually functions as a full fledged usb port, so I’m able to connect a usb3 hub to it using a ‘type-c to a’ adapter and no longer need to pass through an additional pci-e usb card!

The hub is being powered by the usb port, and has a keyboard, mouse and usb DAC connected with zero issues.

Seeing as these cards are quite new and virtualization is a bit niche, I thought I’d put this down in a post for people to see.

SgtAwesomesauce · January 16, 2019, 8:55pm

We’ve had RGB controllers without a serial bus device for years. Not sure why that’d change.

That said, thanks for the interesting report. This is quite interesting.

Zibob · January 16, 2019, 9:00pm

Wendell is due a 2060 soon apparently so maybe he will turn up something like this?

billington.mark · January 16, 2019, 9:33pm

I’d imagine so… I think all the 20 series have the usb type-c port

Zibob · January 16, 2019, 10:27pm

Oh yeah. I completely forgot they had the Type-C on them, well that explains a lot of that.

Now I wonder can it be used for anything fun that was not intended.

gamebrigada · January 17, 2019, 12:32am

Boom, solved Linus’s problem for his multi-user rig he’s been fighting.

Ruffalo · January 17, 2019, 1:20am

Yeppers, the USB port is intended for VR. It’s called VirtualLink, passes through video, audio, data, and power to a VR headset with a single cable. But you can use it as a normal USB 3.1 port, attach a hub, etc. Would be really nice for eGPU use also, once it makes it down to cheaper cards.

https://sites.google.com/view/virtuallink-consortium/home

rockking · January 17, 2019, 1:34am

For real though. It would completely eliminate the need for that daughter board he added with a ton of USB cards.

billington.mark · January 17, 2019, 8:16am

My thoughts exactly when I tested this and it ‘just worked’!

Dje4321 · January 17, 2019, 8:20am

@LinusTech

Zibob · January 17, 2019, 11:24am

You mean like plugging an eGPU into the internal GPU? Would be amazing if this could make some bizarre CrossFire work but that just imagination.

Or just having the card basically sitting on the desk with just external power and USB-C connecting it to the PC. That actually sounds really cool, a raw card, no PCIe plugged in just power and USB and it works, but I don’t know how that would or even if it can work like that.

billington.mark · January 17, 2019, 11:28am

I thought eGPU enclosures needed thunderbolt 3? This is just USB 3.1 gen2 I believe? Maybe with some fairydust sprinkled on top in this case with it being called a “VirtualLink” port.

VirtualLink is designed to enable a new level of immersion in VR, with power, display, and data bandwidth specified to meet the needs of future VR headsets. That includes support for four lanes of HBR3 DisplayPort for high-resolution displays, USB 3.1 Gen2 (SuperSpeed USB 10Gbps) for headset cameras and sensors, and up to 27 Watts of power delivery.

I have seen some posts on the UnRaid forum where people have passed through a thunderbolt 3 PCIe card and had an external GPU enclosure plugged in though. But thats a little off topic

Zibob · January 17, 2019, 11:31am

Yeah you are right. I was just imagining the impossible because it sounds cool. I am sure there can be something fun done with it though.

billington.mark · January 17, 2019, 11:42am

So… now this has had chance to sink in… something like this (link below) would mean a VM, with ONLY the graphics card passed through (no vfio NIC either) could get Display, SD Card reader, USB, Audio and Ethernet from a single usb type-c cable out of the back of the graphics card:

https://eshop.macsales.com/shop/usb-c/owc/usb-c-dock?_ga=2.106044099.1573206853.1547725073-230729525.1547725073

Only thing im not sure about is what’s driving the monitors plugged into that… whether there’s some kind of cheap-o GPU built into the hub, or i’ll get driven by the 20series card?

For a host running multiple VMs (especially those who need to be on different networks), this would be pretty cool.
Essentially takes away the need to set up networking on the VMs on the host (as you can plug a physical Ethernet cable into each) too.
if you’re running 10GbE on the host, you’ll be sacrificing some bandwidth obviously, but being able to run everything from a single cable out of the GPU is pretty interesting!

Zibob · January 17, 2019, 12:12pm

You were right the first time. This could be plugged into the 20xx card but it would only be USB-C 3.1 Gen 2. Mac has thunderbolt 3 so can pass its own display/graphics through this dock, I don’t think the 20xx cards could.

Ruffalo · January 17, 2019, 1:04pm

No, I’m talking about TB3 eGPU enclosures. Many of the cheaper ones don’t have USB ports built in, which kinda takes away the point of the things, where one cable does everything.

alphazero1990 · January 17, 2019, 2:21pm

This is some next level. In other scenarios. It would be nice for anybody with restricted physical pcie or a small form factor iGPU+dedicated setup. Sadly the new Vega doesn’t have this feature.