Bug#570365: nvidia-glx: problem confirmed in with latest xen hypervisor

[Andreas Beckmann]

Hi Michel,

something you could try is to patch nv-linux.h in /usr/src/nvidia*/ and
change the following:

Change the line

    #if defined(CONFIG_XEN) && !defined(CONFIG_PARAVIRT)

to

    #if defined(CONFIG_XEN) // && !defined(CONFIG_PARAVIRT)

and rebuild the module.

Only try this with the xen kernel running under the hypervisor. This
patch will probably break the nvidia module that is currently working
for normal kernel and the xen kernel running not under the hypervisor.

The intention of this patch is to explicitely reactiviate some old style
behaviour described in this comment in nv-linux.h, but I don't know if
the kernel still compiles in this mode:

/*
 * Traditionally, CONFIG_XEN indicated that the target kernel was
 * built exclusively for use under a Xen hypervisor, requiring
 * modifications to or disabling of a variety of NVIDIA graphics
 * driver code paths. As of the introduction of CONFIG_PARAVIRT
 * and support for Xen hypervisors within the CONFIG_PARAVIRT_GUEST
 * architecture, CONFIG_XEN merely indicates that the target
 * kernel can run under a Xen hypervisor, but not that it will.
 *
 * If CONFIG_XEN and CONFIG_PARAVIRT are defined, the old Xen
 * specific code paths are disabled. If the target kernel executes
 * stand-alone, the NVIDIA graphics driver will work fine. If the
 * kernels executes under a Xen (or other) hypervisor, however, the
 * NVIDIA graphics driver has no way of knowing and is unlikely
 * to work correctly.
 */

If this still does not reactivate xen support under hypervisor, that
configuration is probably unsupported by upstream. At least upstream
docs do not say anything about xen at all ...
In that case I have no further clues and the only thing we can document
is: does not work in the xen kernel running under the hypervisor.
Or is there some xen patch for current drivers that I'm not aware of?

Andreas