[PATCH] paravirt: header and stubs for paravirtualisation

Create a paravirt.h header for all the critical operations which need to be
replaced with hypervisor calls, and include that instead of defining native
operations, when CONFIG_PARAVIRT.

This patch does the dumbest possible replacement of paravirtualized
instructions: calls through a "paravirt_ops" structure.  Currently these are
function implementations of native hardware: hypervisors will override the ops
structure with their own variants.

All the pv-ops functions are declared "fastcall" so that a specific
register-based ABI is used, to make inlining assember easier.

And:

+From: Andy Whitcroft <apw@shadowen.org>

The paravirt ops introduce a 'weak' attribute onto memory_setup().
Code ordering leads to the following warnings on x86:

    arch/i386/kernel/setup.c:651: warning: weak declaration of
                `memory_setup' after first use results in unspecified behavior

Move memory_setup() to avoid this.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Zachary Amsden <zach@vmware.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Andy Whitcroft <apw@shadowen.org>
diff --git a/arch/i386/power/cpu.c b/arch/i386/power/cpu.c
index 5a1abef..2c15500 100644
--- a/arch/i386/power/cpu.c
+++ b/arch/i386/power/cpu.c
@@ -26,8 +26,8 @@
 	/*
 	 * descriptor tables
 	 */
- 	store_gdt(&ctxt->gdt_limit);
- 	store_idt(&ctxt->idt_limit);
+ 	store_gdt(&ctxt->gdt);
+ 	store_idt(&ctxt->idt);
  	store_tr(ctxt->tr);
 
 	/*
@@ -99,8 +99,8 @@
 	 * now restore the descriptor tables to their proper values
 	 * ltr is done i fix_processor_context().
 	 */
- 	load_gdt(&ctxt->gdt_limit);
- 	load_idt(&ctxt->idt_limit);
+ 	load_gdt(&ctxt->gdt);
+ 	load_idt(&ctxt->idt);
 
 	/*
 	 * segment registers