linux-kernel - Re: [PATCH V4] x86: call smp vmxoff in smp stop

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Message-ID: <3d5bf4c2-7415-a976-62fb-ba653f92eada@redhat.com>
Date:   Tue, 18 Apr 2017 15:34:28 +0200
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Xishi Qiu <qiuxishi@...wei.com>, Ingo Molnar <mingo@...hat.com>,
        "H. Peter Anvin" <hpa@...or.com>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        the arch/x86 maintainers <x86@...nel.org>,
        wanpeng.li@...mail.com, Andrew Morton <akpm@...ux-foundation.org>,
        hidehiro.kawai.ez@...achi.com, LKML <linux-kernel@...r.kernel.org>,
        Fengtiantian <fengtiantian@...wei.com>,
        Xiexiuqi <xiexiuqi@...wei.com>
Subject: Re: [PATCH V4] x86: call smp vmxoff in smp stop

Ingo, can you put this in tip?

Thanks,

Paolo

On 18/01/2017 12:32, Xishi Qiu wrote:
> From: Tiantian Feng <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: Tiantian Feng <fengtiantian@...wei.com>
> Signed-off-by: Xishi Qiu <qiuxishi@...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();
>  }
>