Index: sys/cam/cam_sim.h
===================================================================
--- sys/cam/cam_sim.h
+++ sys/cam/cam_sim.h
@@ -62,6 +62,15 @@
 				int max_dev_transactions,
 				int max_tagged_dev_transactions,
 				struct cam_devq *queue);
+struct cam_sim *  cam_sim_alloc_dev(sim_action_func sim_action,
+				sim_poll_func sim_poll,
+				const char *sim_name,
+				void *softc,
+				device_t dev,
+				struct mtx *mtx,
+				int max_dev_transactions,
+				int max_tagged_dev_transactions,
+				struct cam_devq *queue);
 void		  cam_sim_free(struct cam_sim *sim, int free_devq);
 void		  cam_sim_hold(struct cam_sim *sim);
 void		  cam_sim_release(struct cam_sim *sim);
@@ -109,6 +118,7 @@
 	struct callout		callout;
 	struct cam_devq 	*devq;	/* Device Queue to use for this SIM */
 	int			refcount; /* References to the SIM. */
+	device_t		sim_dev; /* For attached peripherals. */
 };
 
 #define CAM_SIM_LOCK(sim)	mtx_lock((sim)->mtx)
Index: sys/cam/cam_sim.c
===================================================================
--- sys/cam/cam_sim.c
+++ sys/cam/cam_sim.c
@@ -37,6 +37,7 @@
 #include <sys/kernel.h>
 #include <sys/lock.h>
 #include <sys/mutex.h>
+#include <sys/bus.h>
 
 #include <cam/cam.h>
 #include <cam/cam_ccb.h>
@@ -82,6 +83,7 @@
 	sim->sim_name = sim_name;
 	sim->softc = softc;
 	sim->path_id = CAM_PATH_ANY;
+	sim->dev = NULL;	/* set only by cam_sim_alloc_dev */
 	sim->unit_number = unit;
 	sim->bus_id = 0;	/* set in xpt_bus_register */
 	sim->max_tagged_dev_openings = max_tagged_dev_transactions;
@@ -100,6 +102,25 @@
 	return (sim);
 }
 
+struct cam_sim *
+cam_sim_alloc_dev(sim_action_func sim_action, sim_poll_func sim_poll,
+	      const char *sim_name, void *softc, device_t dev,
+	      struct mtx *mtx, int max_dev_transactions,
+	      int max_tagged_dev_transactions, struct cam_devq *queue)
+{
+	struct cam_sim *sim;
+
+	KASSERT(dev != NULL, ("%s: dev is null for sim_name %s softc %p\n",
+	    __func__, sim_name, softc));
+
+	sim = cam_sim_alloc(sim_action, sim_poll, sim_name, softc,
+	    device_get_unit(dev), mtx, max_dev_transactions,
+	    max_tagged_dev_transactions, queue);
+	if (sim != NULL)
+		sim->sim_dev = dev;
+	return (sim);
+}
+
 void
 cam_sim_free(struct cam_sim *sim, int free_devq)
 {
Index: sys/dev/sdhci/sdhci.c
===================================================================
--- sys/dev/sdhci/sdhci.c
+++ sys/dev/sdhci/sdhci.c
@@ -2487,8 +2487,8 @@
 		goto fail;
 
 	mtx_init(&slot->sim_mtx, "sdhcisim", NULL, MTX_DEF);
-	slot->sim = cam_sim_alloc(sdhci_cam_action, sdhci_cam_poll,
-	    "sdhci_slot", slot, device_get_unit(slot->bus),
+	slot->sim = cam_sim_alloc_dev(sdhci_cam_action, sdhci_cam_poll,
+	    "sdhci_slot", slot, slot->bus,
 	    &slot->sim_mtx, 1, 1, slot->devq);
 
 	if (slot->sim == NULL) {