Re: [Qemu-devel] USB passthrough in qemu

[Gerd Hoffmann]

  Hi,

> However, for the piix4 which is the default platform and is desirable
> due to driver issues in many cases no simple way to instantiate the
> companion setup and have qemu automagically attach the devices
> correctly exists.

We havn't added shortcuts like this to qemu for a while.  There are a
bunch of other new things which don't have a shorthand command line
switch too.  I suspect -usb2 wouldn't be very welcome @ qemu-devel.  You
can try sending a patch though, shouldn't be hard, code is there as q35
uses it.

There is also the option to stick things into a config file (see
docs/q35-chipset.cfg for an example), then do "-readconfig usb2.cfg".

> > If the guest is new enough that it has drivers you can also simply use
> > xhci.
> 
> What xhci hub is emulated?

nec.

> Anyway, xhci drivers for Windows are a mess so this is not going to be
> an option for a while I guess.

Thats why the "if the guest is new enough" above.  With windows this
works nicely only with win8+ (ships with xhci drivers).  For older
windows versions it is not really an option, you'd have to hunt down
drivers on the internet etc.

cheers,
  Gerd