[PATCH] paravirt: header and stubs for paravirtualisation

[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 <[email protected]>

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 <[email protected]>
Signed-off-by: Chris Wright <[email protected]>
Signed-off-by: Andi Kleen <[email protected]>
Cc: Jeremy Fitzhardinge <[email protected]>
Cc: Zachary Amsden <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Andy Whitcroft <[email protected]>