paravirt: helper to disable all IO space

In a virtual environment, device drivers such as legacy IDE will waste
quite a lot of time probing for their devices which will never appear.
This helper function allows a paravirt implementation to lay claim to
the whole iomem and ioport space, thereby disabling all device drivers
trying to claim IO resources.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/include/asm-i386/paravirt.h b/include/asm-i386/paravirt.h
index 7868569..690ada2 100644
--- a/include/asm-i386/paravirt.h
+++ b/include/asm-i386/paravirt.h
@@ -262,6 +262,7 @@
 unsigned paravirt_patch_insns(void *site, unsigned len,
 			      const char *start, const char *end);
 
+int paravirt_disable_iospace(void);
 
 /*
  * This generates an indirect call based on the operation type number.