[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>

arch/i386/kernel/setup.c

@@ -495,6 +495,12 @@ static void set_mca_bus(int x)
 static void set_mca_bus(int x) { }
 #endif
 
+/* Overridden in paravirt.c if CONFIG_PARAVIRT */
+char * __attribute__((weak)) memory_setup(void)
+{
+	return machine_specific_memory_setup();
+}
+
 /*
  * Determine if we were loaded by an EFI loader.  If so, then we have also been
  * passed the efi memmap, systab, etc., so we should use these data structures
@@ -547,7 +553,7 @@ void __init setup_arch(char **cmdline_p)
 		efi_init();
 	else {
 		printk(KERN_INFO "BIOS-provided physical RAM map:\n");
-		print_memory_map(machine_specific_memory_setup());
+		print_memory_map(memory_setup());
 	}
 
 	copy_edd();