[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>

1 files changed, 10 insertions, 6 deletions

diff --git a/include/asm-i386/system.h b/include/asm-i386/system.h
index a6dabbcd6e6..a6d20d9a1a3 100644
--- a/include/asm-i386/system.h
+++ b/include/asm-i386/system.h
@@ -88,6 +88,9 @@ __asm__ __volatile__ ("movw %%dx,%1\n\t" \
 #define savesegment(seg, value) \
 	asm volatile("mov %%" #seg ",%0":"=rm" (value))
 
+#ifdef CONFIG_PARAVIRT
+#include <asm/paravirt.h>
+#else
 #define read_cr0() ({ \
 	unsigned int __dummy; \
 	__asm__ __volatile__( \
@@ -139,17 +142,18 @@ __asm__ __volatile__ ("movw %%dx,%1\n\t" \
 #define write_cr4(x) \
 	__asm__ __volatile__("movl %0,%%cr4": :"r" (x))
 
-/*
- * Clear and set 'TS' bit respectively
- */
+#define wbinvd() \
+	__asm__ __volatile__ ("wbinvd": : :"memory")
+
+/* Clear the 'TS' bit */
 #define clts() __asm__ __volatile__ ("clts")
+#endif/* CONFIG_PARAVIRT */
+
+/* Set the 'TS' bit */
 #define stts() write_cr0(8 | read_cr0())
 
 #endif	/* __KERNEL__ */
 
-#define wbinvd() \
-	__asm__ __volatile__ ("wbinvd": : :"memory")
-
 static inline unsigned long get_limit(unsigned long segment)
 {
 	unsigned long __limit;