Since the NAS was going to be a typical tower and in the living room, the overarching goal was to make it also have the functionality of a gaming PC. To get true USB Hot-Plugging will require us to pass through an entire USB controller just like we did the Pascal GPU. We’ve covered the basics of IOMMU groups, and most server / workstation hardware (CPUs, motherboards, and chipsets) would make this pretty easy. However, I put this together out of older hardware I had laying around. Specifically, I have a Zen 1 Ryzen 7 1700 dropped into an X370 motherboard (MSI X370 Gaming Pro). Since all this hardware was made for “consumers”, the designers did not put a lot of thought into how things can be isolated and virtualized. So, the next step I need to take is to map all the IOMMU groups to actual devices on the motherboard.

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