linux-kernel - [RFC PATCH] x86: call smp vmxoff in smp stop

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Date:   Wed, 4 Jan 2017 18:11:38 +0800
From:   Xishi Qiu <qiuxishi@...wei.com>
To:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "H. Peter Anvin" <hpa@...or.com>,
        the arch/x86 maintainers <x86@...nel.org>,
        <wanpeng.li@...mail.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        <hidehiro.kawai.ez@...achi.com>, <pbonzini@...hat.com>
CC:     LKML <linux-kernel@...r.kernel.org>,
        Fengtiantian <fengtiantian@...wei.com>,
        Xiexiuqi <xiexiuqi@...wei.com>
Subject: [RFC PATCH] x86: call smp vmxoff in smp stop

From: f00186668 <fengtiantian@...wei.com>

We need to disable VMX on all CPUs before stop cpu when OS panic, otherwisewe
risk hanging up the machine, because the CPU ignore INIT signals when VMX is enabled.
In kernel mainline this issue existence.

Signed-off-by: f00186668 <fengtiantian@...wei.com>
---
 arch/x86/kernel/smp.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/x86/kernel/smp.c b/arch/x86/kernel/smp.c
index 68f8cc2..6b64c6b 100644
--- a/arch/x86/kernel/smp.c
+++ b/arch/x86/kernel/smp.c
@@ -162,6 +162,7 @@ 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 +175,7 @@ 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();
 }
-- 
1.8.3.1