I never had any problems with vbox usb passthru from lin.host to win.guest, so you might have a really specific case here, but I know there are loads of people running
qemu on lin.host with all kinds of advanced hardware pass through configurations.
Thinking about it, if you have a very old motherboard the IOMMU layout might have hindered proper hardware separation.
Comments
Anything what needs to touch hardware is not going to work.
Not true, usb and pci passthrough is a thing.
Works with very narrow set of hardware when stars align correctly and there is not too many spots on the Sun. Usually utterly useless in practice
VMware Workstation passthoughs are very reliable for me. I can't say the same for VirtualBox though.
My experience for generic Virtual Serial Port hardware
* MacOS Parallels - Abysmal performance, constant USB timeouts. Virtually useless
* Virtual box on Windows, emulating Windows - Able to detect device, but unable to talk to it.
* Virtual box on Linux emulating Windows - USB does not even detect.
I never had any problems with vbox usb passthru from lin.host to win.guest, so you might have a really specific case here, but I know there are loads of people running qemu on lin.host with all kinds of advanced hardware pass through configurations.
Thinking about it, if you have a very old motherboard the IOMMU layout might have hindered proper hardware separation.
But I doubt OP really need pass-through at all.