Re: [PATCH v1 01/13] xen/pvcalls: introduce the pvcalls xenbus frontend

[Stefano Stabellini]

On Mon, 24 Jul 2017, Juergen Gross wrote:
> On 22/07/17 02:11, Stefano Stabellini wrote:
> > Introduce a xenbus frontend for the pvcalls protocol, as defined by
> > https://xenbits.xen.org/docs/unstable/misc/pvcalls.html.
> > 
> > This patch only adds the stubs, the code will be added by the following
> > patches.
> > 
> > Signed-off-by: Stefano Stabellini <stefano@xxxxxxxxxxx>
> > CC: boris.ostrovsky@xxxxxxxxxx
> > CC: jgross@xxxxxxxx
> > ---
> >  drivers/xen/pvcalls-front.c | 68 +++++++++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 68 insertions(+)
> >  create mode 100644 drivers/xen/pvcalls-front.c
> > 
> > diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c
> > new file mode 100644
> > index 0000000..173e204
> > --- /dev/null
> > +++ b/drivers/xen/pvcalls-front.c
> > @@ -0,0 +1,68 @@
> > +/*
> > + * (c) 2017 Stefano Stabellini <stefano@xxxxxxxxxxx>
> > + *
> > + * This program is free software; you can redistribute it and/or modify
> > + * it under the terms of the GNU General Public License as published by
> > + * the Free Software Foundation; either version 2 of the License, or
> > + * (at your option) any later version.
> > + *
> > + * This program is distributed in the hope that it will be useful,
> > + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> > + * GNU General Public License for more details.
> > + */
> > +
> > +#include <linux/module.h>
> > +
> > +#include <xen/events.h>
> > +#include <xen/grant_table.h>
> > +#include <xen/xen.h>
> > +#include <xen/xenbus.h>
> > +#include <xen/interface/io/pvcalls.h>
> > +
> > +static const struct xenbus_device_id pvcalls_front_ids[] = {
> > +	{ "pvcalls" },
> > +	{ "" }
> > +};
> > +
> > +static int pvcalls_front_remove(struct xenbus_device *dev)
> > +{
> > +	return 0;
> > +}
> > +
> > +static int pvcalls_front_probe(struct xenbus_device *dev,
> > +			  const struct xenbus_device_id *id)
> > +{
> > +	return 0;
> > +}
> > +
> > +static int pvcalls_front_resume(struct xenbus_device *dev)
> > +{
> > +	dev_warn(&dev->dev, "suspsend/resume unsupported\n");
> > +	return 0;
> > +}
> 
> Why are you adding a resume function doing nothing but issuing a
> message? Just omit it.

I'll do, thanks!


> > +
> > +static void pvcalls_front_changed(struct xenbus_device *dev,
> > +			    enum xenbus_state backend_state)
> > +{
> > +}
> > +
> > +static struct xenbus_driver pvcalls_front_driver = {
> > +	.ids = pvcalls_front_ids,
> > +	.probe = pvcalls_front_probe,
> > +	.remove = pvcalls_front_remove,
> > +	.resume = pvcalls_front_resume,
> > +	.otherend_changed = pvcalls_front_changed,
> > +};
> > +
> > +static int __init pvcalls_frontend_init(void)
> > +{
> > +	if (!xen_domain())
> > +		return -ENODEV;
> > +
> > +	pr_info("Initialising Xen pvcalls frontend driver\n");
> > +
> > +	return xenbus_register_frontend(&pvcalls_front_driver);
> > +}
> > +
> > +module_init(pvcalls_frontend_init);
> > 
>