4.9-stable review patch. If anyone has any objections, please let me know.
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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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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(); }