This commit replaces the mapping of DMA buffers and gets rid of the
bounce-buffer handling, which was introduced to prevent data
corruption noticed when utilizing USB storage with Windows 10 guests,
with accessing the buffers directly.
Due to the way Windows 10 at times manages its DMA memory (many small
pieces instead of few larger ones) the unbounded registry becomes a
problem when containing stale entries.
Changing the 'qemu-usb' implementation allows for using 'read_dma'
and 'write_dma' directly.
Fixes#5121.
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.
