Re: back/frontend drivers HelloWorld

[NAHieu <nahieu@gmail.com>]

On 9/25/05, Keir Fraser <Keir.Fraser@cl.cam.ac.uk> wrote:
>
> On 25 Sep 2005, at 17:24, NAHieu wrote:
>
> > - Is that correct? ( I have some doubts about (2), as I see that the
> > drivers available in xen uses xenbus_driver.probe to detect domU's
> > driver?)
>
> All correct, but you skip a few details.
>
> In step 1, domU gets the event channel port via EVTCHNOP_alloc_unbound.
> It then writes that port value to xenstore.
>
> In step 2, dom0 binds to the remote event-channel port via
> EVTCHNOP_bind_interdomain. This returns the allocated local port which
> is what is passed to bind_evtchn_to_irqhandler().
> See code in drivers/xen/blkback/interface.c for a precise example of
> doing this -- probably best to steal that portion of code as a
> template.
>
> Also, you can find code in blkfront/blkback to allocate a shared page
> in blkfront, allocate a grant reference for it, pass that to blkback
> and map the page thru the grant reference.
>

I looked at some frontend code, and they all exploit the xenbus_driver
(and the needed common fields are .ids, .probe and .remove ). So it is
mandatory for all backend/frontend (regardless of real or virtual
device) to do like that ?

Keir, thank you a lot.
Hieu