Index: sys/amd64/vmm/io/iommu.c
===================================================================
--- sys/amd64/vmm/io/iommu.c	(revision 260864)
+++ sys/amd64/vmm/io/iommu.c	(working copy)
@@ -33,6 +33,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/types.h>
 #include <sys/systm.h>
 #include <sys/bus.h>
+#include <sys/sysctl.h>
 
 #include <dev/pci/pcivar.h>
 #include <dev/pci/pcireg.h>
@@ -43,7 +44,13 @@ __FBSDID("$FreeBSD$");
 #include "vmm_mem.h"
 #include "iommu.h"
 
-static boolean_t iommu_avail;
+SYSCTL_DECL(_hw_vmm);
+SYSCTL_NODE(_hw_vmm, OID_AUTO, iommu, CTLFLAG_RW, 0, "bhyve iommu parameters");
+
+static int iommu_avail;
+SYSCTL_INT(_hw_vmm_iommu, OID_AUTO, initialized, CTLFLAG_RD, &iommu_avail,
+    0, "bhyve iommu initialized?");
+
 static struct iommu_ops *ops;
 static void *host_domain;
 
@@ -160,7 +167,7 @@ iommu_init(void)
 	if (error)
 		return;
 
-	iommu_avail = TRUE;
+	iommu_avail = 1;
 
 	/*
 	 * Create a domain for the devices owned by the host
Index: sys/amd64/vmm/io/ppt.c
===================================================================
--- sys/amd64/vmm/io/ppt.c	(revision 260864)
+++ sys/amd64/vmm/io/ppt.c	(working copy)
@@ -38,6 +38,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/pciio.h>
 #include <sys/rman.h>
 #include <sys/smp.h>
+#include <sys/sysctl.h>
 
 #include <dev/pci/pcivar.h>
 #include <dev/pci/pcireg.h>
@@ -100,7 +101,12 @@ static struct pptdev {
 	} msix;
 } pptdevs[64];
 
+SYSCTL_DECL(_hw_vmm);
+SYSCTL_NODE(_hw_vmm, OID_AUTO, ppt, CTLFLAG_RW, 0, "bhyve passthru devices");
+
 static int num_pptdevs;
+SYSCTL_INT(_hw_vmm_ppt, OID_AUTO, devices, CTLFLAG_RD, &num_pptdevs, 0,
+    "number of pci passthru devices");
 
 static int
 ppt_probe(device_t dev)
@@ -282,8 +288,15 @@ ppt_teardown_msix(struct pptdev *ppt)
 }
 
 int
-ppt_num_devices(struct vm *vm)
+ppt_avail_devices(void)
 {
+
+	return (num_pptdevs);
+}
+
+int
+ppt_assigned_devices(struct vm *vm)
+{
 	int i, num;
 
 	num = 0;
Index: sys/amd64/vmm/io/ppt.h
===================================================================
--- sys/amd64/vmm/io/ppt.h	(revision 260864)
+++ sys/amd64/vmm/io/ppt.h	(working copy)
@@ -36,10 +36,16 @@ int	ppt_setup_msi(struct vm *vm, int vcpu, int bus
 		      uint64_t addr, uint64_t msg, int numvec);
 int	ppt_setup_msix(struct vm *vm, int vcpu, int bus, int slot, int func,
 		int idx, uint64_t addr, uint64_t msg, uint32_t vector_control);
-int	ppt_num_devices(struct vm *vm);
+int	ppt_assigned_devices(struct vm *vm);
 boolean_t ppt_is_mmio(struct vm *vm, vm_paddr_t gpa);
 
 /*
+ * Returns the number of devices sequestered by the ppt driver for assignment
+ * to virtual machines.
+ */
+int	ppt_avail_devices(void);
+
+/*
  * The following functions should never be called directly.
  * Use 'vm_assign_pptdev()' and 'vm_unassign_pptdev()' instead.
  */
Index: sys/amd64/vmm/vmm.c
===================================================================
--- sys/amd64/vmm/vmm.c	(revision 260864)
+++ sys/amd64/vmm/vmm.c	(working copy)
@@ -266,7 +266,8 @@ vmm_handler(module_t mod, int what, void *arg)
 	switch (what) {
 	case MOD_LOAD:
 		vmmdev_init();
-		iommu_init();
+		if (ppt_avail_devices() > 0)
+			iommu_init();
 		error = vmm_init();
 		if (error == 0)
 			vmm_initialized = 1;
@@ -604,7 +605,7 @@ vm_unassign_pptdev(struct vm *vm, int bus, int slo
 	if (error)
 		return (error);
 
-	if (ppt_num_devices(vm) == 0) {
+	if (ppt_assigned_devices(vm) == 0) {
 		vm_iommu_unmap(vm);
 		vm_gpa_unwire(vm);
 	}
@@ -624,7 +625,7 @@ vm_assign_pptdev(struct vm *vm, int bus, int slot,
 	 *
 	 * We need to do this before the first pci passthru device is attached.
 	 */
-	if (ppt_num_devices(vm) == 0) {
+	if (ppt_assigned_devices(vm) == 0) {
 		KASSERT(vm->iommu == NULL,
 		    ("vm_assign_pptdev: iommu must be NULL"));
 		maxaddr = vmm_mem_maxaddr();