Recently I picked up one of the Radeon Pro Duos (Polaris) from Newegg’s Ebay page and wanted to get it set up for VFIO passthrough for 2 separate Windows VMs.
I’m using Ubuntu 18.04 LTS as the host OS running off a GT 710 GPU. On initial boot with amdgpu drivers the card shows up as a single WX 7100.
IOMMU groups show up as such:
IOMMU Group 24 03:00.0 VGA compatible controller [0300]: Advanced Micro Devices, Inc. [AMD/ATI] Ellesmere [Radeon Pro WX 7100] [1002:67c4]
IOMMU Group 24 03:00.1 Audio device [0403]: Advanced Micro Devices, Inc [AMD/ATI] Ellesmere [Radeon RX 580] [1002:aaf0]
IOMMU Group 25 04:00.0 Display controller [0380]: Advanced Micro Devices, Inc. [AMD/ATI] Ellesmere [Radeon Pro WX 7100] [1002:67c4]
By the looks of it I probably won’t be able to claim 2 separate GPUs with vfio-pci but I want to make sure if this is usually the case with dual-GPU cards with a PLX controller.
The IOMMU groups are separated so the only problem is that one card does not have a output. This looks like a norm for dual cards.
You could try to set one VM to be used only via RDP. Or you could try to use looking glass. But that one needs connected monitor. Dont know if the pro driver can emulate that.
Maybe adding a DRM lease into a mix to separate one of the GT 710 output, dedicating it to looking glass.
Would be fun to tinker around.
I was actually planning on using steam link streaming for both VMs. I have done this in the past with GTX 1060s and it worked really well for minimal clutter setup at LAN parties. I would set up VNC on the Windows VMs as RDP would disable GPU hardware acceleration and lock out Steam.
Still I’d like to look into getting the second GPU recognized or powered up in some way. Digging through dmesg shows that it initialized a WX 7100 with 16GB of vram. Each GPU has 16GB so the second GPU is definitely not getting recognized in any way. Looking for the PLX chip is also a bit tricky as this Gigabyte X79 UD3 motherboard may have one as well.