KVM: Wake up waitqueue before calling get_cpu()

This moves the get_cpu() call down to be called after we wake up the
waiters. Therefore the waitqueue locks can safely be rt mutex.

Signed-off-by: Jan Blunck <jblunck@suse.de>
Signed-off-by: Sven-Thorsten Dietrich <sven@thebigcorporation.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

Author: Jan Blunck

arch/x86/kvm/x86.c

@@ -4569,7 +4569,7 @@ static void vcpu_kick_intr(void *info)
 void kvm_vcpu_kick(struct kvm_vcpu *vcpu)
 {
 	int ipi_pcpu = vcpu->cpu;
-	int cpu = get_cpu();
+	int cpu;
 
 	if (waitqueue_active(&vcpu->wq)) {
 		wake_up_interruptible(&vcpu->wq);
@@ -4579,6 +4579,7 @@ void kvm_vcpu_kick(struct kvm_vcpu *vcpu)
 	 * We may be called synchronously with irqs disabled in guest mode,
 	 * So need not to call smp_call_function_single() in that case.
 	 */
+	cpu = get_cpu();
 	if (vcpu->guest_mode && vcpu->cpu != cpu)
 		smp_call_function_single(ipi_pcpu, vcpu_kick_intr, vcpu, 0);
 	put_cpu();