Index: sys/dev/virtio/pci/virtio_pci.c
===================================================================
--- sys/dev/virtio/pci/virtio_pci.c
+++ sys/dev/virtio/pci/virtio_pci.c
@@ -67,6 +67,7 @@
 
 struct vtpci_softc {
 	device_t			 vtpci_dev;
+	int				 vtpci_res_type;
 	struct resource			*vtpci_res;
 	struct resource			*vtpci_msix_res;
 	uint64_t			 vtpci_features;
@@ -275,20 +276,31 @@
 static int
 vtpci_attach(device_t dev)
 {
+	const int res_types[] = { SYS_RES_IOPORT, SYS_RES_MEMORY };
 	struct vtpci_softc *sc;
 	device_t child;
 	int rid;
+	int i;
 
 	sc = device_get_softc(dev);
 	sc->vtpci_dev = dev;
 
 	pci_enable_busmaster(dev);
 
-	rid = PCIR_BAR(0);
-	sc->vtpci_res = bus_alloc_resource_any(dev, SYS_RES_IOPORT, &rid,
-	    RF_ACTIVE);
+	/*
+	 * Most hypervisors export the common configuration structure in IO
+	 * space, but some use memory space; try both.
+	 */
+	for (i = 0; nitems(res_types); i++) {
+		rid = PCIR_BAR(0);
+		sc->vtpci_res_type = res_types[i];
+		sc->vtpci_res = bus_alloc_resource_any(dev, res_types[i], &rid,
+		    RF_ACTIVE);
+		if (sc->vtpci_res != NULL)
+			break;
+	}
 	if (sc->vtpci_res == NULL) {
-		device_printf(dev, "cannot map I/O space\n");
+		device_printf(dev, "cannot map I/O nor memory space\n");
 		return (ENXIO);
 	}
 
@@ -347,7 +359,7 @@
 	}
 
 	if (sc->vtpci_res != NULL) {
-		bus_release_resource(dev, SYS_RES_IOPORT, PCIR_BAR(0),
+		bus_release_resource(dev, sc->vtpci_res_type, PCIR_BAR(0),
 		    sc->vtpci_res);
 		sc->vtpci_res = NULL;
 	}