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KVM: Fix reboot on Intel hosts

commit ca242ac upstream.

When we reboot, we disable vmx extensions or otherwise INIT gets blocked.
If a task on another cpu hits a vmx instruction, it will fault if vmx is
disabled.  We trap that to avoid a nasty oops and spin until the reboot

Problem is, we sleep with interrupts disabled.  This blocks smp_send_stop()
from running, and the reboot process halts.

Fix by enabling interrupts before spinning.

Signed-off-by: Avi Kivity <>
Signed-off-by: Marcelo Tosatti <>
Signed-off-by: Greg Kroah-Hartman <>
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1 parent 85aa428 commit 8706a900f0c047b49e34918cdf2b23dc82c234d5 Marcelo Tosatti committed with gregkh Oct 14, 2010
Showing with 3 additions and 1 deletion.
  1. +3 −1 virt/kvm/kvm_main.c
4 virt/kvm/kvm_main.c
@@ -1942,10 +1942,12 @@ static int kvm_cpu_hotplug(struct notifier_block *notifier, unsigned long val,
asmlinkage void kvm_handle_fault_on_reboot(void)
- if (kvm_rebooting)
+ if (kvm_rebooting) {
/* spin while reset goes on */
+ local_irq_enable();
while (true)
+ }
/* Fault while not rebooting. We want the trace. */

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