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Commit fba4f472 authored by Tiantian Feng's avatar Tiantian Feng Committed by Ingo Molnar
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x86/reboot: Turn off KVM when halting a CPU 



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: default avatarTiantian Feng <fengtiantian@huawei.com>
Signed-off-by: default avatarXishi Qiu <qiuxishi@huawei.com>
[ Rewritten commit message. ]
Signed-off-by: default avatarPaolo 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: default avatarIngo Molnar <mingo@kernel.org>
parent d594aa02

arch/x86/kernel/smp.c

+3 −0
Original line number Diff line number Diff line
@@ -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();

}