Re: [Qemu-devel] Add virtual devices to QEMU

[Stefan Hajnoczi]

On Mon, Jun 25, 2012 at 11:59 AM, Alberich de megres
<address@hidden> wrote:
> Together with some colleagues, we are developing a USB hardware. But
> as the prototype is not ready to be built, and is not cheap,
> or idea is to develop at the same time a virtual device for the qemu.
>
> I searched for documentation about the USB layer on qemu but I could
> not find a good point. Which would be a good starting point (in the
> qemu)? is it better to create a new machine type? or make it a command
> line option ike --mynew-usb-dev?

If you want to prototype a USB device (e.g. a TV tuner card) then
neither a new machine type nor command-line option is necessary.
Follow what hw/usb/dev-*.c do.  The USB serial device looks like a
simple example of how to implement USB device emulation.

There is also USB redirection over network support in
hw/usb/redirect.c which may make development easier for you since it
allows you to implement your prototype as a separate process with less
QEMU-specific infrastructure.

There is not much developer documentation, you need to dig into the
code.  Learn from the existing devices.

Stefan