KVM: set debug registers after "schedulable" section

The vcpu thread can be preempted after the guest_debug_pre() callback,
resulting in invalid debug registers on the new vcpu.

Move it inside the non-preemptable section.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

arch/x86/kvm/x86.c

@@ -3113,10 +3113,6 @@ static int __vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 	down_read(&vcpu->kvm->slots_lock);
 	vapic_enter(vcpu);
 
-preempted:
-	if (vcpu->guest_debug.enabled)
-		kvm_x86_ops->guest_debug_pre(vcpu);
-
 again:
 	if (vcpu->requests)
 		if (test_and_clear_bit(KVM_REQ_MMU_RELOAD, &vcpu->requests))
@@ -3170,6 +3166,9 @@ static int __vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 		goto out;
 	}
 
+	if (vcpu->guest_debug.enabled)
+		kvm_x86_ops->guest_debug_pre(vcpu);
+
 	vcpu->guest_mode = 1;
 	/*
 	 * Make sure that guest_mode assignment won't happen after
@@ -3244,7 +3243,7 @@ static int __vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 	if (r > 0) {
 		kvm_resched(vcpu);
 		down_read(&vcpu->kvm->slots_lock);
-		goto preempted;
+		goto again;
 	}
 
 	post_kvm_run_save(vcpu, kvm_run);