port-xen/51080: Support pvfb on xen domu (patch)

[pablo%polvorin.com.ar@localhost]

>Number:         51080
>Category:       port-xen
>Synopsis:       Support pvfb on xen domu (patch)
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    port-xen-maintainer
>State:          open
>Class:          change-request
>Submitter-Id:   net
>Arrival-Date:   Wed Apr 20 22:20:00 +0000 2016
>Originator:     Pablo Polvorin
>Release:        7.0
>Organization:
>Environment:
>Description:
The patch is available here http://blog.polvorin.com.ar/patches/pvfb.patch

is an attempt at supporting the virtual framebuffer on xen guest
( http://wiki.netbsd.org/projects/project/xen-domu-pvfb/ )

Basic functionality is in place, but reached a point where guidance/feedback would be very welcome in order to push this forward,
this is the first piece of kernel code I attempt to write, and I'm not
that familiar with netbsd to start with.

Need to review, at least

* Memory management (conversion to frame number to pass references to xen host).  Currently save/restore isn't working,  but neither do it  without this patch on my install.

* code just act as a kind of adapter between xenbus and genfb, wskbddev and wsmousedev, letting them attach to xenbus. Is that the way to go?

* The way I added the drivers to be used by autoconf


There is a little bit more description at http://blog.polvorin.com.ar/2016/04/20/netbsd-pvfb.html 






>How-To-Repeat:

>Fix:
above patch