Attached; look broken to me although I'm no expert.
Group 9 is broken. Intel Chipsets since Skylake have a rather innofensive ACS related errata for the Chipset PCIe Root Ports that requires a Linux Kernel workaround, which is applied on a per-PCIID basis. Since Xeons C246 Chipset is new, chances are than its PCIID is not included when applying the errata workaround. If it is so, it isn't Supermicro related at all and should affect all C246 based Motherboards.
I can batcall the main VFIO developer to check into that, he is usually on Reddit VFIO subreddit. It may be possible that you have to recompile the Linux Kernel with his fix to check if it works.
BTW, just in case, drop also a full lspci -vvvnn. According to the
quirks file...
Per the datasheet[5], root port PCI Device IDs for this* chipset include:
This works based on the PCIID of the PCIe Root Ports themselves. Since Intel seems to not have released a Data Sheet for the C246 Chipsets (Intel did released a Data Sheet for most of the other 300 series Chipsets except Z390), you need to get info by yourself about what the PCIID target is. The same series usually have the same PCIID for the Root Ports, so unless the C246 uses different ones than the rest of the 300 series it should already been workarounded.
Also, for good measure, include a lspci -xxxx of the PCIe Root Ports so you get the PCI Configuration Space, check
here. That one would actually be Supermicro fault if they are not exposing ACS correctly.
Finally, what distribution and Linux Kernel are you using? If it is too old, it may be possible that they do not include the quirks for the Coffee Point Chipset series.
