This is a note to let you know that I've just added the patch titled
x86/reboot: Turn off KVM when halting a CPU
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
x86-reboot-turn-off-kvm-when-halting-a-cpu.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Thu Mar 22 14:40:23 CET 2018
From: Tiantian Feng <fengtiantian@xxxxxxxxxx>
Date: Wed, 19 Apr 2017 18:18:39 +0200
Subject: x86/reboot: Turn off KVM when halting a CPU
From: Tiantian Feng <fengtiantian@xxxxxxxxxx>
[ Upstream commit fba4f472b33aa81ca1836f57d005455261e9126f ]
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@xxxxxxxxxx>
Signed-off-by: Xishi Qiu <qiuxishi@xxxxxxxxxx>
[ Rewritten commit message. ]
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: kvm@xxxxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/20170419161839.30550-1-pbonzini@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kernel/smp.c | 3 +++
1 file changed, 3 insertions(+)
--- 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(unsigne
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(unsigne
asmlinkage __visible void smp_reboot_interrupt(void)
{
ipi_entering_ack_irq();
+ cpu_emergency_vmxoff();
stop_this_cpu(NULL);
irq_exit();
}
Patches currently in stable-queue which might be from fengtiantian@xxxxxxxxxx are
queue-4.9/x86-reboot-turn-off-kvm-when-halting-a-cpu.patch