KVM: arm/arm64: Fix young bit from mmu notifier

kvm_test_age_hva() is called upon mmu_notifier_test_young(), but wrong
address range has been passed to handle_hva_to_gpa(). With the wrong
address range, no young bits will be checked in handle_hva_to_gpa().
It means zero is always returned from mmu_notifier_test_young().

This fixes the issue by passing correct address range to the underly
function handle_hva_to_gpa(), so that the hardware young (access) bit
will be visited.

Fixes: 35307b9a5f ("arm/arm64: KVM: Implement Stage-2 page aging")
Signed-off-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200121055659.19560-1-gshan@redhat.com

virt/kvm/arm/mmu.c

@@ -2144,7 +2144,8 @@ int kvm_test_age_hva(struct kvm *kvm, unsigned long hva)
 	if (!kvm->arch.pgd)
 		return 0;
 	trace_kvm_test_age_hva(hva);
-	return handle_hva_to_gpa(kvm, hva, hva, kvm_test_age_hva_handler, NULL);
+	return handle_hva_to_gpa(kvm, hva, hva + PAGE_SIZE,
+				 kvm_test_age_hva_handler, NULL);
 }
 
 void kvm_mmu_free_memory_caches(struct kvm_vcpu *vcpu)