The contrib code is updated from 2.4.1 to version 5.2.0 and the used
device-model is changed to QEMU xHCI. Due to this change older guests
OSes, namely Windows 7, that relied on the NEC xHCI device-model will
not work anymore.
The 'Qemu::Controller' interface was extended by an 'info' method, which
returns the vendor and product ID. This allows for removing the
hard-coded values in the VirtualBox glue code.
Issue #4018.
The former implemention assumed that the guest physical memory is
mapped continously. This, however, is not true. Writing larger
files to an USB stick with a Windows 10 guest would therefore lead
to data corruption.
The current implementation uses a bounce buffer to copy the data
to and from the guest physical memory and leaves dealing with the
memory mappings entirely up to the VMM.
Fixes#4017.
