lkml.org 
[lkml]   [2018]   [Mar]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH AUTOSEL for 4.9 052/190] x86/reboot: Turn off KVM when halting a CPU
Date
From: Tiantian Feng <fengtiantian@huawei.com>

[ 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@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>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.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 ca699677e288..ea217caa731c 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();
}
--
2.14.1
\
 
 \ /
  Last update: 2018-03-08 07:19    [W:0.571 / U:0.820 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site