From: Glauber Costa <glommer@redhat.com>
Date: Tue, 11 Aug 2009 13:32:06 -0400
Subject: [x86] disable kvmclock when shuting the machine down
Message-id: 1250011926-31633-8-git-send-email-glommer@redhat.com
O-Subject: [PATCH v2 7/7] disable kvmclock when shuting the machine down
Bugzilla: 476075

if we don't do this, the clock will be kept running, and if the machine
does not really go down (kexec, for instance), the new kernel will have
part of its memory overwritten.

This is explained in commit 1e977aa12dd4f80688b1f243762212e75c6d7fe8
in upstream kernel

Signed-off-by: Glauber Costa <glommer@redhat.com>

diff --git a/arch/i386/kernel/crash.c b/arch/i386/kernel/crash.c
index 615878f..26554bf 100644
--- a/arch/i386/kernel/crash.c
+++ b/arch/i386/kernel/crash.c
@@ -23,6 +23,7 @@
 #include <asm/hw_irq.h>
 #include <asm/apic.h>
 #include <mach_ipi.h>
+#include <linux/kvm_para.h>
 
 
 /* This keeps a track of which one is crashing cpu. */
@@ -159,6 +160,9 @@ static void nmi_shootdown_cpus(void)
 
 void machine_crash_shutdown(struct pt_regs *regs)
 {
+#ifndef CONFIG_XEN
+	kvmclock_disable();
+#endif
 	/* This function is only called after the system
 	 * has panicked or is otherwise in a critical state.
 	 * The minimum amount of code to allow a kexec'd kernel
diff --git a/arch/i386/kernel/reboot.c b/arch/i386/kernel/reboot.c
index bbd0862..601072f 100644
--- a/arch/i386/kernel/reboot.c
+++ b/arch/i386/kernel/reboot.c
@@ -17,6 +17,7 @@
 #include <asm/desc.h>
 #include "mach_reboot.h"
 #include <linux/reboot_fixups.h>
+#include <linux/kvm_para.h>
 
 /*
  * Power off function, if any
@@ -312,6 +313,9 @@ void machine_shutdown(void)
 	smp_send_stop();
 #endif /* CONFIG_SMP */
 
+#ifndef CONFIG_XEN
+	kvmclock_disable();
+#endif
 	lapic_shutdown();
 
 #ifdef CONFIG_X86_IO_APIC
diff --git a/arch/x86_64/kernel/crash.c b/arch/x86_64/kernel/crash.c
index d02e355..baebf74 100644
--- a/arch/x86_64/kernel/crash.c
+++ b/arch/x86_64/kernel/crash.c
@@ -24,7 +24,7 @@
 #include <asm/nmi.h>
 #include <asm/hw_irq.h>
 #include <asm/mach_apic.h>
-
+#include <linux/kvm_para.h>
 #ifndef CONFIG_XEN
 #include <asm/virtext.h>
 #endif
@@ -177,6 +177,10 @@ static void nmi_shootdown_cpus(void)
 extern struct pci_dev *mcp55_rewrite;
 void machine_crash_shutdown(struct pt_regs *regs)
 {
+
+#ifndef CONFIG_XEN
+	kvmclock_disable();
+#endif
 	/*
 	 * This function is only called after the system
 	 * has panicked or is otherwise in a critical state.
diff --git a/arch/x86_64/kernel/reboot.c b/arch/x86_64/kernel/reboot.c
index 5b14772..849990a 100644
--- a/arch/x86_64/kernel/reboot.c
+++ b/arch/x86_64/kernel/reboot.c
@@ -17,6 +17,7 @@
 #include <asm/tlbflush.h>
 #include <asm/apic.h>
 #include <asm/proto.h>
+#include <linux/kvm_para.h>
 
 /*
  * Power off function, if any
@@ -112,6 +113,10 @@ void machine_shutdown(void)
 	smp_send_stop();
 #endif
 
+#ifndef CONFIG_XEN
+	kvmclock_disable();
+#endif
+
 	local_irq_save(flags);
 
 #ifndef CONFIG_SMP