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x86/reboot: Turn off KVM when halting a CPU

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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>
This commit is contained in:
Tiantian Feng 2017-04-19 18:18:39 +02:00 committed by Ingo Molnar
parent d594aa0277
commit fba4f472b3
1 changed files with 3 additions and 0 deletions
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3
arch/x86/kernel/smp.c
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@ -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();
}