Index: share/man/man4/pci.4
===================================================================
--- share/man/man4/pci.4
+++ share/man/man4/pci.4
@@ -492,6 +492,55 @@
 pin identified by the tunable name.
 Mapping of IRQ values to platform interrupt sources is machine dependent.
 .El
+.Sh DEVICE WIRING
+You can wire the device unit at a given location with device.hints.
+Entries of the form
+.Va hints.<name>.<unit>.at="pci<B>:<S>:<F>"
+or
+.Va hints.<name>.<unit>.at="pci<D>:<B>:<S>:<F>"
+will force the driver
+.Va name
+to probe and attach at unit
+.Va unit
+for any PCI device found to match the specification, where:
+.Bl -tag -width -indent
+.It <D>
+The domain
+.Pq or segment
+of the PCI device in decimal.
+Defaults to 0 if unspecified
+.It <B>
+The bus address of the PCI device in decimal.
+.It <S>
+The slot of the PCI device in decimal.
+.It <F>
+The function of the PCI device in decimal.
+.El
+.Pp
+The code to do the matching requires an exact string match.
+Do not specify the angle brackets
+.Pq < >
+in the hints file.
+Wiring multiple devices to the same
+.Va name
+and
+.Va unit
+produces undefined results.
+.Ss Examples
+Given the following lines in
+.Pa /boot/device.hints :
+.Cd hint.nvme.3.at="pci6:0:0"
+.Cd hint.igb.8.at="pci14:0:0"
+If there's a device that supports igb at PCI bus 14 slot 0 function 0,
+then it will be assigned igb8 for probe and attach.
+Likewise, if there's an NVMe card at PCI bus 6 slot 0 function 0,
+then it will be assigned nvme3 for probe and attach.
+If another type of card is in either of these locations, the name and
+unit of that card will be the default names and will be unaffected by
+these hints.
+If other igb or nvme cards are located elsewhere, they will be
+assigned their unit numbers sequentially, skipping the unit numbers
+that have 'at' hints.
 .Sh FILES
 .Bl -tag -width /dev/pci -compact
 .It Pa /dev/pci
Index: sys/cam/cam_ccb.h
===================================================================
--- sys/cam/cam_ccb.h
+++ sys/cam/cam_ccb.h
@@ -633,6 +633,11 @@
 
 struct ccb_pathinq_settings_nvme {
 	uint32_t nsid;		/* Namespace ID for this path */
+	uint32_t domain;
+	uint8_t  bus;
+	uint8_t  slot;
+	uint8_t  function;
+	uint8_t  extra;
 };
 
 #define	PATHINQ_SETTINGS_SIZE	128
Index: sys/dev/acpica/acpi.c
===================================================================
--- sys/dev/acpica/acpi.c
+++ sys/dev/acpica/acpi.c
@@ -1019,7 +1019,8 @@
 	    break;
 
 	/* Must have an "at" for acpi or isa. */
-	resource_string_value(name, unit, "at", &s);
+	if (resource_string_value(name, unit, "at", &s) != 0)
+		continue;
 	if (!(strcmp(s, "acpi0") == 0 || strcmp(s, "acpi") == 0 ||
 	    strcmp(s, "isa0") == 0 || strcmp(s, "isa") == 0))
 	    continue;
Index: sys/dev/nvme/nvme_sim.c
===================================================================
--- sys/dev/nvme/nvme_sim.c
+++ sys/dev/nvme/nvme_sim.c
@@ -182,7 +182,8 @@
 		break;
 	case XPT_PATH_INQ:		/* Path routing inquiry */
 	{
-		struct ccb_pathinq *cpi = &ccb->cpi;
+		struct ccb_pathinq	*cpi = &ccb->cpi;
+		device_t		dev = ctrlr->dev;
 
 		/*
 		 * NVMe may have multiple LUNs on the same path. Current generation
@@ -210,6 +211,11 @@
 		cpi->protocol = PROTO_NVME;
 		cpi->protocol_version = nvme_mmio_read_4(ctrlr, vs);
 		cpi->xport_specific.nvme.nsid = ns->id;
+		cpi->xport_specific.nvme.domain = pci_get_domain(dev);
+		cpi->xport_specific.nvme.bus = pci_get_bus(dev);
+		cpi->xport_specific.nvme.slot = pci_get_slot(dev);
+		cpi->xport_specific.nvme.function = pci_get_function(dev);
+		cpi->xport_specific.nvme.extra = 0;
 		cpi->ccb_h.status = CAM_REQ_CMP;
 		break;
 	}
Index: sys/dev/pci/pci.c
===================================================================
--- sys/dev/pci/pci.c
+++ sys/dev/pci/pci.c
@@ -123,6 +123,8 @@
 static void		pci_resume_msix(device_t dev);
 static int		pci_remap_intr_method(device_t bus, device_t dev,
 			    u_int irq);
+static void		pci_hint_device_unit(device_t acdev, device_t child,
+			    const char *name, int *unitp);
 
 static int		pci_get_id_method(device_t dev, device_t child,
 			    enum pci_id_type type, uintptr_t *rid);
@@ -162,6 +164,7 @@
 	DEVMETHOD(bus_child_detached,	pci_child_detached),
 	DEVMETHOD(bus_child_pnpinfo_str, pci_child_pnpinfo_str_method),
 	DEVMETHOD(bus_child_location_str, pci_child_location_str_method),
+	DEVMETHOD(bus_hint_device_unit,	pci_hint_device_unit),
 	DEVMETHOD(bus_remap_intr,	pci_remap_intr_method),
 	DEVMETHOD(bus_suspend_child,	pci_suspend_child),
 	DEVMETHOD(bus_resume_child,	pci_resume_child),
@@ -4220,6 +4223,39 @@
 	return (device_delete_children(dev));
 }
 
+static void
+pci_hint_device_unit(device_t dev, device_t child, const char *name, int *unitp)
+{
+	int line, unit;
+	const char *at;
+	char me1[20], me2[30];
+	uint8_t b, s, f;
+	uint32_t d;
+
+	line = 0;
+	d = pci_get_domain(child);
+	b = pci_get_bus(child);
+	s = pci_get_slot(child);
+	f = pci_get_function(child);
+	/*
+	 * asprintf would be handier and more stack friendly, but
+	 * we get called when WAITOK is not allowed.
+	 */
+	snprintf(me1, sizeof(me1), "pci%u:%u:%u", b, s, f);
+	snprintf(me2, sizeof(me2), "pci%u:%u:%u:%u", d, b, s, f);
+	for (;;) {
+		if (resource_find_dev(&line, name, &unit, "at", NULL) != 0)
+			break;
+		if (resource_string_value(name, unit, "at", &at) != 0)
+			continue;
+		if (strcmp(at, me1) != 0 &&
+		    strcmp(at, me2) != 0)
+			continue;
+		*unitp = unit;
+		break;
+	}
+}
+
 static void
 pci_set_power_child(device_t dev, device_t child, int state)
 {