Index: share/man/man9/pci.9
===================================================================
--- share/man/man9/pci.9
+++ share/man/man9/pci.9
@@ -149,6 +149,10 @@
 .Fn pcie_read_config "device_t dev" "int reg" "int width"
 .Ft void
 .Fn pcie_write_config "device_t dev" "int reg" "uint32_t val" "int width"
+.Ft void
+.Fn pci_event_fn "void *arg" "device_t dev"
+.Fn EVENTHANDLER_REGISTER "pci_add_device" "pci_event_fn"
+.Fn EVENTHANDLER_DEREGISTER "pci_delete_resource" "pci_event_fn"
 .In dev/pci/pci_iov.h
 .Ft int
 .Fn pci_iov_attach "device_t dev" "nvlist_t *pf_schema" "nvlist_t *vf_schema"
@@ -910,6 +914,24 @@
 The
 .Fn pci_remap_msix
 function will fail if this condition is not met.
+.Ss Device Events
+The
+.Va pci_add_device
+event handler is invoked every time a new PCI device is added to the system.
+This includes the creation of Virtual Functions via SR-IOV.
+.Pp
+The
+.Va pci_delete_device
+event handler is invoked every time a PCI device is removed from the system.
+.Pp
+Both event handlers pass the
+.Vt device_t
+object of the relevant PCI device as
+.Fa dev
+to each callback function.
+Both event handlers are invoked while
+.Fa dev
+is unattached but with valid instance variables.
 .Sh SEE ALSO
 .Xr pci 4 ,
 .Xr pciconf 8 ,
@@ -921,6 +943,7 @@
 .Xr devclass 9 ,
 .Xr device 9 ,
 .Xr driver 9 ,
+.Xr eventhandler 9 ,
 .Xr rman 9
 .Rs
 .%B FreeBSD Developers' Handbook
Index: sys/amd64/vmm/io/iommu.c
===================================================================
--- sys/amd64/vmm/io/iommu.c
+++ sys/amd64/vmm/io/iommu.c
@@ -58,6 +58,7 @@
 
 static struct iommu_ops *ops;
 static void *host_domain;
+static eventhandler_tag add_tag, delete_tag;
 
 static __inline int
 IOMMU_INIT(void)
@@ -154,6 +155,22 @@
 }
 
 static void
+iommu_pci_add(void *arg, device_t dev)
+{
+
+	/* Add new devices to the host domain. */
+	iommu_add_device(host_domain, pci_get_rid(dev));
+}
+
+static void
+iommu_pci_delete(void *arg, device_t dev)
+{
+
+	/* XXX: Remove doesn't really need a domain. */
+	iommu_remove_device(host_domain, pci_get_rid(dev));
+}
+
+static void
 iommu_init(void)
 {
 	int error, bus, slot, func;
@@ -195,6 +212,9 @@
 	 */
 	iommu_create_mapping(host_domain, 0, 0, maxaddr);
 
+	add_tag = EVENTHANDLER_REGISTER(pci_add_device, iommu_pci_add, NULL, 0);
+	delete_tag = EVENTHANDLER_REGISTER(pci_delete_device, iommu_pci_delete,
+	    NULL, 0);
 	for (bus = 0; bus <= PCI_BUSMAX; bus++) {
 		for (slot = 0; slot <= PCI_SLOTMAX; slot++) {
 			for (func = 0; func <= PCI_FUNCMAX; func++) {
@@ -215,6 +235,15 @@
 void
 iommu_cleanup(void)
 {
+
+	if (add_tag != NULL) {
+		EVENTHANDLER_DEREGISTER(pci_add_device, add_tag);
+		add_tag = NULL;
+	}
+	if (delete_tag != NULL) {
+		EVENTHANDLER_DEREGISTER(pci_delete_device, delete_tag);
+		delete_tag = NULL;
+	}
 	IOMMU_DISABLE();
 	IOMMU_DESTROY_DOMAIN(host_domain);
 	IOMMU_CLEANUP();
Index: sys/dev/pci/pci.c
===================================================================
--- sys/dev/pci/pci.c
+++ sys/dev/pci/pci.c
@@ -4071,6 +4071,7 @@
 	pci_print_verbose(dinfo);
 	pci_add_resources(bus, dinfo->cfg.dev, 0, 0);
 	pci_child_added(dinfo->cfg.dev);
+	EVENTHANDLER_INVOKE(pci_add_device, dinfo->cfg.dev);
 }
 
 void
@@ -5312,6 +5313,8 @@
 	dinfo = device_get_ivars(child);
 	rl = &dinfo->resources;
 
+	EVENTHANDLER_INVOKE(pci_delete_device, child);
+
 	/* Turn off access to resources we're about to free */
 	if (bus_child_present(child) != 0) {
 		pci_write_config(child, PCIR_COMMAND, pci_read_config(child,
Index: sys/dev/pci/pcivar.h
===================================================================
--- sys/dev/pci/pcivar.h
+++ sys/dev/pci/pcivar.h
@@ -31,6 +31,7 @@
 #define	_PCIVAR_H_
 
 #include <sys/queue.h>
+#include <sys/eventhandler.h>
 
 /* some PCI bus constants */
 #define	PCI_MAXMAPS_0	6	/* max. no. of memory/port maps */
@@ -631,4 +632,12 @@
 void	vga_pci_unmap_bios(device_t dev, void *bios);
 int	vga_pci_repost(device_t dev);
 
+/**
+ * Global eventhandlers invoked when PCI devices are added or removed
+ * from the system.
+ */
+typedef void (*pci_event_fn)(void *arg, device_t dev);
+EVENTHANDLER_DECLARE(pci_add_device, pci_event_fn);
+EVENTHANDLER_DECLARE(pci_delete_device, pci_event_fn);
+
 #endif /* _PCIVAR_H_ */