KVM: PPC: Book3S HV P9: Add kvmppc_stop_thread to match kvmppc_start_thread

Small cleanup makes it a bit easier to match up entry and exit
operations.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211123095231.1036501-22-npiggin@gmail.com

arch/powerpc/kvm/book3s_hv.c

@@ -3070,6 +3070,13 @@ static void kvmppc_start_thread(struct kvm_vcpu *vcpu, struct kvmppc_vcore *vc)
 		kvmppc_ipi_thread(cpu);
 }
 
+/* Old path does this in asm */
+static void kvmppc_stop_thread(struct kvm_vcpu *vcpu)
+{
+	vcpu->cpu = -1;
+	vcpu->arch.thread_cpu = -1;
+}
+
 static void kvmppc_wait_for_nap(int n_threads)
 {
 	int cpu = smp_processor_id();
@@ -4310,8 +4317,6 @@ static int kvmhv_p9_guest_entry(struct kvm_vcpu *vcpu, u64 time_limit,
 		dec = (s32) dec;
 	tb = mftb();
 	vcpu->arch.dec_expires = dec + tb;
-	vcpu->cpu = -1;
-	vcpu->arch.thread_cpu = -1;
 
 	store_spr_state(vcpu);
 
@@ -4808,6 +4813,8 @@ int kvmhv_run_single_vcpu(struct kvm_vcpu *vcpu, u64 time_limit,
 	}
 	vtime_account_guest_exit();
 
+	kvmppc_stop_thread(vcpu);
+
 	powerpc_local_irq_pmu_restore(flags);
 
 	cpumask_clear_cpu(pcpu, &kvm->arch.cpu_in_guest);