From 658dc56c1098e1d516beb9899bb5d04a1ba7ba73 Mon Sep 17 00:00:00 2001
From: Eduardo Habkost <ehabkost@redhat.com>
Date: Wed, 15 Dec 2010 10:44:48 -0200
Subject: [PATCH 2/2] Revert "KVM: Don't spin on virt instruction faults during reboot"

RH-Reverts: 5222476aa2e8eeafdd6d9bc11b213c093b82e84a
RH-Reverts-patchwork-id: 14220
Bugzilla-related: 608709
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
---
 arch/x86/include/asm/kvm_host.h |    8 ++------
 virt/kvm/kvm_main.c             |   13 +++++++++----
 2 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index e60478d..b9dff51 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -737,18 +737,14 @@ enum {
  * reboot turns off virtualization while processes are running.
  * Trap the fault and ignore the instruction if that happens.
  */
-asmlinkage void kvm_spurious_fault(void);
-extern bool kvm_rebooting;
+asmlinkage void kvm_handle_fault_on_reboot(void);
 
 #define __kvm_handle_fault_on_reboot(insn) \
 	"666: " insn "\n\t" \
-	"668: \n\t"                           \
 	".pushsection .fixup, \"ax\" \n" \
 	"667: \n\t" \
-	"cmpb $0, kvm_rebooting \n\t"	      \
-	"jne 668b \n\t"      		      \
 	__ASM_SIZE(push) " $666b \n\t"	      \
-	"call kvm_spurious_fault \n\t"	      \
+	"jmp kvm_handle_fault_on_reboot \n\t" \
 	".popsection \n\t" \
 	".pushsection __ex_table, \"a\" \n\t" \
 	_ASM_PTR " 666b, 667b \n\t" \
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 6766b91..02b858a 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -77,8 +77,7 @@ struct dentry *kvm_debugfs_dir;
 static long kvm_vcpu_ioctl(struct file *file, unsigned int ioctl,
 			   unsigned long arg);
 
-bool kvm_rebooting;
-EXPORT_SYMBOL_GPL(kvm_rebooting);
+static bool kvm_rebooting;
 
 #ifdef KVM_CAP_DEVICE_ASSIGNMENT
 static struct kvm_assigned_dev_kernel *kvm_find_assigned_dev(struct list_head *head,
@@ -2404,12 +2403,18 @@ static int kvm_cpu_hotplug(struct notifier_block *notifier, unsigned long val,
 }
 
 
-asmlinkage void kvm_spurious_fault(void)
+asmlinkage void kvm_handle_fault_on_reboot(void)
 {
+	if (kvm_rebooting) {
+		/* spin while reset goes on */
+		local_irq_enable();
+		while (true)
+			;
+	}
 	/* Fault while not rebooting.  We want the trace. */
 	BUG();
 }
-EXPORT_SYMBOL_GPL(kvm_spurious_fault);
+EXPORT_SYMBOL_GPL(kvm_handle_fault_on_reboot);
 
 static int kvm_reboot(struct notifier_block *notifier, unsigned long val,
 		      void *v)
-- 
1.7.3.2