diff --git a/virt/kvm/iommu.c b/virt/kvm/iommu.c
index fec1723de9b4..e9fff9830bf0 100644
--- a/virt/kvm/iommu.c
+++ b/virt/kvm/iommu.c
@@ -240,9 +240,13 @@ int kvm_iommu_map_guest(struct kvm *kvm)
 		return -ENODEV;
 	}
 
+	mutex_lock(&kvm->slots_lock);
+
 	kvm->arch.iommu_domain = iommu_domain_alloc(&pci_bus_type);
-	if (!kvm->arch.iommu_domain)
-		return -ENOMEM;
+	if (!kvm->arch.iommu_domain) {
+		r = -ENOMEM;
+		goto out_unlock;
+	}
 
 	if (!allow_unsafe_assigned_interrupts &&
 	    !iommu_domain_has_cap(kvm->arch.iommu_domain,
@@ -253,17 +257,16 @@ int kvm_iommu_map_guest(struct kvm *kvm)
 		       " module option.\n", __func__);
 		iommu_domain_free(kvm->arch.iommu_domain);
 		kvm->arch.iommu_domain = NULL;
-		return -EPERM;
+		r = -EPERM;
+		goto out_unlock;
 	}
 
 	r = kvm_iommu_map_memslots(kvm);
 	if (r)
-		goto out_unmap;
+		kvm_iommu_unmap_memslots(kvm);
 
-	return 0;
-
-out_unmap:
-	kvm_iommu_unmap_memslots(kvm);
+out_unlock:
+	mutex_unlock(&kvm->slots_lock);
 	return r;
 }
 
@@ -340,7 +343,11 @@ int kvm_iommu_unmap_guest(struct kvm *kvm)
 	if (!domain)
 		return 0;
 
+	mutex_lock(&kvm->slots_lock);
 	kvm_iommu_unmap_memslots(kvm);
+	kvm->arch.iommu_domain = NULL;
+	mutex_unlock(&kvm->slots_lock);
+
 	iommu_domain_free(domain);
 	return 0;
 }