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From 7737fc421365d9f2fd328b19fdccf005092d4ec1 Mon Sep 17 00:00:00 2001
From: Tiantian Feng <fengtiantian@huawei.com>
Date: Wed, 19 Apr 2017 18:18:39 +0200
Subject: [PATCH 08/93] x86/reboot: Turn off KVM when halting a CPU
[ Upstream commit fba4f472b33aa81ca1836f57d005455261e9126f ]
A CPU in VMX root mode will ignore INIT signals and will fail to bring
up the APs after reboot. Therefore, on a panic we disable VMX on all
CPUs before rebooting or triggering kdump.
Do this when halting the machine as well, in case a firmware-level reboot
does not perform a cold reset for all processors. Without doing this,
rebooting the host may hang.
Signed-off-by: Tiantian Feng <fengtiantian@huawei.com>
Signed-off-by: Xishi Qiu <qiuxishi@huawei.com>
[ Rewritten commit message. ]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kvm@vger.kernel.org
Link: http://lkml.kernel.org/r/20170419161839.30550-1-pbonzini@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/kernel/smp.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/arch/x86/kernel/smp.c b/arch/x86/kernel/smp.c
index c00cb64..420f2dc 100644
--- a/arch/x86/kernel/smp.c
+++ b/arch/x86/kernel/smp.c
@@ -33,6 +33,7 @@
#include <asm/mce.h>
#include <asm/trace/irq_vectors.h>
#include <asm/kexec.h>
+#include <asm/virtext.h>
/*
* Some notes on x86 processor bugs affecting SMP operation:
@@ -162,6 +163,7 @@ static int smp_stop_nmi_callback(unsigned int val, struct pt_regs *regs)
if (raw_smp_processor_id() == atomic_read(&stopping_cpu))
return NMI_HANDLED;
+ cpu_emergency_vmxoff();
stop_this_cpu(NULL);
return NMI_HANDLED;
@@ -174,6 +176,7 @@ static int smp_stop_nmi_callback(unsigned int val, struct pt_regs *regs)
asmlinkage __visible void smp_reboot_interrupt(void)
{
ipi_entering_ack_irq();
+ cpu_emergency_vmxoff();
stop_this_cpu(NULL);
irq_exit();
}
--
2.7.4
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