IOMMU groups for Thunderbolt 4

[joevt]

@Kieran_Levin

The laptop has the 4 physical ports split into two logical PCIE devices. With the ports on the left side going to one controller and the ports on the right side going to the second controller. So I think if you were ok with 2 ports on one side going to your VM, I think you could use the ports on the other side with your host OS.

I think there is only one USB 3.1 gen 2 controller shared by all 4 ports. So maybe you could split the Thunderbolt PCIe root ports and USB4 controllers between guest and host OSs but USB 3.x functionality would be weird (if it’s not USB from a Thunderbolt device using tunnelled PCIe). I’m not sure since I don’t have any experience with Tiger Lake or with VMs that can take over a PCIe device. I know VMs can take over specific USB devices without taking over the PCIe controller so maybe there’s a work around if there’s a problem.

4 thunderbolt ports on the model? 40GBps on each port?

Framework uses Tiger Lake CPU which has integrated USB4/Thunderbolt 4 controller so it wouldn’t need a JHL8540 Maple Ridge discrete Thunderbolt controller. Maybe it uses JHL8040R Retimer? Anyway, with TigerLake Thunderbolt 4: There’s one USB controller for the USB 3.1 gen 2 functionality of all four ports. Probably this also gets used for USB tunnelling functionality of the USB4 controller when a USB4 dock/hub is connected. There’s two (I guess one for each side?) NHI controllers (USB4 cont…