From 582200e9e7b6132bcc89980e68d8e3335819775f Mon Sep 17 00:00:00 2001
From: Avi Kivity <avi@redhat.com>
Date: Sun, 26 Sep 2010 11:05:15 -0300
Subject: [PATCH] KVM: Fix reboot on Intel hosts

RH-Author: Avi Kivity <avi@redhat.com>
Message-id: <1285499115-9166-1-git-send-email-avi@redhat.com>
Patchwork-id: 12288
O-Subject: [PATCH RHEL5.6 RHEL5.5.z] KVM: Fix reboot on Intel hosts
Bugzilla: 608709
RH-Acked-by: Zachary Amsden <zamsden@redhat.com>
RH-Acked-by: Rik van Riel <riel@redhat.com>
RH-Acked-by: Marcelo Tosatti <mtosatti@redhat.com>

Bugzilla: 608709
Upstream: 706dee0ef50e585f64c1d60ffc60482a6527eaad

When we reboot, we disable vmx extensions or otherwise INIT gets blocked.
If a task on another cpu hits a vmx instruction, it will fault if vmx is
disabled.  We trap that to avoid a nasty oops and spin until the reboot
completes.

Problem is, we sleep with interrupts disabled.  This blocks smp_send_stop()
from running, and the reboot process halts.

Fix by enabling interrupts before spinning.

KVM-Stable-Tag.
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
---
 virt/kvm/kvm_main.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
---
 virt/kvm/kvm_main.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index cd08525..02b858a 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2405,10 +2405,12 @@ static int kvm_cpu_hotplug(struct notifier_block *notifier, unsigned long val,
 
 asmlinkage void kvm_handle_fault_on_reboot(void)
 {
-	if (kvm_rebooting)
+	if (kvm_rebooting) {
 		/* spin while reset goes on */
+		local_irq_enable();
 		while (true)
 			;
+	}
 	/* Fault while not rebooting.  We want the trace. */
 	BUG();
 }
-- 
1.6.5.5