Add accessor methods to fetch the BAR holding the MSI-X table and PBA.

While here, explicitly note the requirement that the BAR(s) must be
allocated prior to calling pci_alloc_msix().

Reviewed by:	andrew, emaste
MFC after:	1 week
Differential Revision:	https://reviews.freebsd.org/D4688

share/man/man9/Makefile

@@ -1287,6 +1287,8 @@ MLINKS+=pci.9 pci_alloc_msi.9 \
 	pci.9 pci_iov_detach.9 \
 	pci.9 pci_msi_count.9 \
 	pci.9 pci_msix_count.9 \
+	pci.9 pci_msix_pba_bar.9 \
+	pci.9 pci_msix_table_bar.9 \
 	pci.9 pci_pending_msix.9 \
 	pci.9 pci_read_config.9 \
 	pci.9 pci_release_msi.9 \

share/man/man9/pci.9

@@ -25,7 +25,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd November 5, 2015
+.Dd December 23, 2015
 .Dt PCI 9
 .Os
 .Sh NAME
@@ -51,6 +51,8 @@
 .Nm pci_iov_detach ,
 .Nm pci_msi_count ,
 .Nm pci_msix_count ,
+.Nm pci_msix_pba_bar ,
+.Nm pci_msix_table_bar ,
 .Nm pci_pending_msix ,
 .Nm pci_read_config ,
 .Nm pci_release_msi ,
@@ -107,6 +109,10 @@
 .Ft int
 .Fn pci_msix_count "device_t dev"
 .Ft int
+.Fn pci_msix_pba_bar "device_t dev"
+.Ft int
+.Fn pci_msix_table_bar "device_t dev"
+.Ft int
 .Fn pci_pending_msix "device_t dev" "u_int index"
 .Ft uint32_t
 .Fn pci_read_config "device_t dev" "int reg" "int width"
@@ -694,6 +700,37 @@ then
 returns zero.
 .Pp
 The
+.Fn pci_msix_pba_bar
+function returns the offset in configuration space of the Base Address Register
+.Pq BAR
+containing the MSI-X Pending Bit Array (PBA) for device
+.Fa dev .
+The returned value can be used as the resource ID with
+.Xr bus_alloc_resource 9
+and
+.Xr bus_release_resource 9
+to allocate the BAR.
+If the device does not support MSI-X,
+then
+.Fn pci_msix_pba_bar
+returns -1.
+.Pp
+The
+.Fn pci_msix_table_bar
+function returns the offset in configuration space of the BAR
+containing the MSI-X vector table for device
+.Fa dev .
+The returned value can be used as the resource ID with
+.Xr bus_alloc_resource 9
+and
+.Xr bus_release_resource 9
+to allocate the BAR.
+If the device does not support MSI-X,
+then
+.Fn pci_msix_table_bar
+returns -1.
+.Pp
+The
 .Fn pci_alloc_msix
 function attempts to allocate
 .Fa *count
@@ -732,12 +769,21 @@ it returns an error.
 Unlike MSI,
 MSI-X does not require message counts that are powers of two.
 .Pp
+The BARs containing the MSI-X vector table and PBA must be
+allocated via
+.Xr bus_alloc_resource 9
+before calling
+.Fn pci_alloc_msix
+and must not be released until after calling
+.Fn pci_release_msi .
+Note that the vector table and PBA may be stored in the same BAR or in
+different BARs.
+.Pp
 The
 .Fn pci_pending_msix
 function examines the
 .Fa dev
-device's Pending Bit Array
-.Pq PBA
+device's PBA
 to determine the pending status of the MSI-X message at table index
 .Fa index .
 If the indicated message is pending,
@@ -853,3 +899,6 @@ These do not refer to the geographic location of PCI devices,
 but to the device number assigned by the combination of the PCI IDSEL
 mechanism and the platform firmware.
 This should be taken note of when working with the kernel PCI code.
+.Pp
+The PCI bus driver should allocate the MSI-X vector table and PBA internally
+as necessary rather than requiring the caller to do so.

sys/dev/pci/pci.c

@@ -187,6 +187,8 @@ static device_method_t pci_methods[] = {
 	DEVMETHOD(pci_release_msi,	pci_release_msi_method),
 	DEVMETHOD(pci_msi_count,	pci_msi_count_method),
 	DEVMETHOD(pci_msix_count,	pci_msix_count_method),
+	DEVMETHOD(pci_msix_pba_bar,	pci_msix_pba_bar_method),
+	DEVMETHOD(pci_msix_table_bar,	pci_msix_table_bar_method),
 	DEVMETHOD(pci_get_rid,		pci_get_rid_method),
 	DEVMETHOD(pci_child_added,	pci_child_added_method),
 #ifdef PCI_IOV
@@ -1851,6 +1853,28 @@ pci_msix_count_method(device_t dev, device_t child)
 	return (0);
 }
 
+int
+pci_msix_pba_bar_method(device_t dev, device_t child)
+{
+	struct pci_devinfo *dinfo = device_get_ivars(child);
+	struct pcicfg_msix *msix = &dinfo->cfg.msix;
+
+	if (pci_do_msix && msix->msix_location != 0)
+		return (msix->msix_pba_bar);
+	return (-1);
+}
+
+int
+pci_msix_table_bar_method(device_t dev, device_t child)
+{
+	struct pci_devinfo *dinfo = device_get_ivars(child);
+	struct pcicfg_msix *msix = &dinfo->cfg.msix;
+
+	if (pci_do_msix && msix->msix_location != 0)
+		return (msix->msix_table_bar);
+	return (-1);
+}
+
 /*
  * HyperTransport MSI mapping control
  */

sys/dev/pci/pci_if.m

@@ -36,7 +36,13 @@ CODE {
 	{
 		return (0);
 	}
-	
+
+	static int
+	null_msix_bar(device_t dev, device_t child)
+	{
+		return (-1);
+	}
+
 	static device_t
 	null_create_iov_child(device_t bus, device_t pf, uint16_t rid,
 	    uint16_t vid, uint16_t did)
@@ -192,6 +198,16 @@ METHOD int msix_count {
 	device_t	child;
 } DEFAULT null_msi_count;
 
+METHOD int msix_pba_bar {
+	device_t	dev;
+	device_t	child;
+} DEFAULT null_msix_bar;
+
+METHOD int msix_table_bar {
+	device_t	dev;
+	device_t	child;
+} DEFAULT null_msix_bar;
+
 METHOD uint16_t get_rid {
 	device_t	dev;
 	device_t	child;

sys/dev/pci/pci_private.h

@@ -102,6 +102,8 @@ int		pci_remap_msix_method(device_t dev, device_t child,
 int		pci_release_msi_method(device_t dev, device_t child);
 int		pci_msi_count_method(device_t dev, device_t child);
 int		pci_msix_count_method(device_t dev, device_t child);
+int		pci_msix_pba_bar_method(device_t dev, device_t child);
+int		pci_msix_table_bar_method(device_t dev, device_t child);
 struct resource	*pci_alloc_resource(device_t dev, device_t child, 
 		    int type, int *rid, u_long start, u_long end, u_long count,
 		    u_int flags);

sys/dev/pci/pcivar.h

@@ -516,6 +516,18 @@ pci_msix_count(device_t dev)
     return (PCI_MSIX_COUNT(device_get_parent(dev), dev));
 }
 
+static __inline int
+pci_msix_pba_bar(device_t dev)
+{
+    return (PCI_MSIX_PBA_BAR(device_get_parent(dev), dev));
+}
+
+static __inline int
+pci_msix_table_bar(device_t dev)
+{
+    return (PCI_MSIX_TABLE_BAR(device_get_parent(dev), dev));
+}
+
 static __inline uint16_t
 pci_get_rid(device_t dev)
 {