diff --git a/sys/amd64/vmm/intel/vtd.c b/sys/amd64/vmm/intel/vtd.c
index 8f06dc823364..21e81223f6ee 100644
--- a/sys/amd64/vmm/intel/vtd.c
+++ b/sys/amd64/vmm/intel/vtd.c
@@ -446,6 +446,8 @@ vtd_add_device(void *arg, uint16_t rid)
 	struct vtdmap *vtdmap;
 	uint8_t bus;
 
+	KASSERT(dom != NULL, ("domain is NULL"));
+
 	bus = PCI_RID2BUS(rid);
 	ctxp = ctx_tables[bus];
 	pt_paddr = vtophys(dom->ptp);
diff --git a/sys/amd64/vmm/io/iommu.c b/sys/amd64/vmm/io/iommu.c
index 6a589f153815..01ce29539ec2 100644
--- a/sys/amd64/vmm/io/iommu.c
+++ b/sys/amd64/vmm/io/iommu.c
@@ -258,6 +258,7 @@ iommu_cleanup(void)
 	}
 	IOMMU_DISABLE();
 	IOMMU_DESTROY_DOMAIN(host_domain);
+	host_domain = NULL;
 	IOMMU_CLEANUP();
 }
 
diff --git a/sys/amd64/vmm/io/ppt.c b/sys/amd64/vmm/io/ppt.c
index edb65a3ac07b..26dad1832b10 100644
--- a/sys/amd64/vmm/io/ppt.c
+++ b/sys/amd64/vmm/io/ppt.c
@@ -182,7 +182,9 @@ ppt_detach(device_t dev)
 	num_pptdevs--;
 	TAILQ_REMOVE(&pptdev_list, ppt, next);
 	pci_disable_busmaster(dev);
-	iommu_add_device(iommu_host_domain(), pci_get_rid(dev));
+
+	if (iommu_host_domain() != NULL)
+		iommu_add_device(iommu_host_domain(), pci_get_rid(dev));
 
 	return (0);
 }