linux-kernel - [RFC PATCH V2] x86: call smp vmxoff in smp stop

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Date:   Thu, 5 Jan 2017 09:45:13 +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 V2] 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 | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/x86/kernel/smp.c b/arch/x86/kernel/smp.c
index 68f8cc2..b574d55 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();
 }
-- 
1.8.3.1