Re: WMI and Kernel:User interface

Darren Hart
2017-06-13T16:24:21Z

On Tue, Jun 13, 2017 at 06:05:47PM +0200, Greg Kroah-Hartman wrote:
> On Tue, Jun 13, 2017 at 08:44:19AM -0700, Darren Hart wrote:
> > > In some cases filter function can be simple in some cases hard. I can
> > > image that usage of while listing, plus in some cases also filtering
> > > (when it would be relatively easy to implement).
> >
> > See my response to Christoph - to address the concern of breaking userspace
> > later, if we consider this a proxy instead of a filter, we can make it
> > transparent to userspace and maintain kernel driver state. The driver can
> > register a wmi_method_proxy callback which can choose to proxy the method call
> > or not. If it does, it can update it's own state and perform the requested
> > action through it's own infrastructure, populate the out buffer and send it back
> > up to userspace. I would hope to see as few of these as possible, but they would
> > allow for protecting the kernel drivers while still enabling userspace usage of
> > WMI.
>
> Ok, I think we need to see some real code here to get any further with
> this. There's a reason we don't do big design discussions without
> patches, as that usually answers all of the questions involved.
>
> Please, let's see some code before anything else.

Agreed. That was my intent earlier with getting the chardev and calling
conventions established.

--
Darren Hart
VMware Open Source Technology Center