i386: Allow selected bug checks to be

From: Rusty Russell <rusty@rustcorp.com.au>

Allow selected bug checks to be skipped by paravirt kernels.  The two most
important are the F00F workaround (which is either done by the hypervisor,
or not required), and the 'hlt' instruction check, which can break under
some hypervisors.

Signed-off-by: Zachary Amsden <zach@vmware.com>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---

 arch/i386/kernel/cpu/intel.c |    2 +-
 include/asm-i386/bugs.h      |    4 ++++
 2 files changed, 5 insertions(+), 1 deletion(-)

Index: linux/arch/i386/kernel/cpu/intel.c
===================================================================
--- linux.orig/arch/i386/kernel/cpu/intel.c
+++ linux/arch/i386/kernel/cpu/intel.c
@@ -107,7 +107,7 @@ static void __cpuinit init_intel(struct 
 	 * Note that the workaround only should be initialized once...
 	 */
 	c->f00f_bug = 0;
-	if ( c->x86 == 5 ) {
+	if (!paravirt_enabled() && c->x86 == 5) {
 		static int f00f_workaround_enabled = 0;
 
 		c->f00f_bug = 1;
Index: linux/include/asm-i386/bugs.h
===================================================================
--- linux.orig/include/asm-i386/bugs.h
+++ linux/include/asm-i386/bugs.h
@@ -21,6 +21,7 @@
 #include <asm/processor.h>
 #include <asm/i387.h>
 #include <asm/msr.h>
+#include <asm/paravirt.h>
 
 static int __init no_halt(char *s)
 {
@@ -91,6 +92,9 @@ static void __init check_fpu(void)
 
 static void __init check_hlt(void)
 {
+	if (paravirt_enabled())
+		return;
+
 	printk(KERN_INFO "Checking 'hlt' instruction... ");
 	if (!boot_cpu_data.hlt_works_ok) {
 		printk("disabled\n");