[PATCH v2] xen PV passthru: assign SR-IOV virtual functions to separate virtual slots

[Laszlo Ersek <lersek@redhat.com>]

VFs are reported as single-function devices in PCI_HEADER_TYPE, which
causes pci_scan_slot() in the PV domU to skip all VFs beyond #0 in the
pciback-provided slot. Avoid this by assigning each VF to a separate
virtual slot.

Signed-off-by: Laszlo Ersek <lersek@redhat.com>
---
v1->v2:
* avoid extra indentation
* make sure virtual functions are assigned with func=0

 drivers/xen/xen-pciback/vpci.c |   14 ++++++++++----
 1 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/drivers/xen/xen-pciback/vpci.c b/drivers/xen/xen-pciback/vpci.c
index 46d140b..0f478ac 100644
--- a/drivers/xen/xen-pciback/vpci.c
+++ b/drivers/xen/xen-pciback/vpci.c
@@ -89,9 +89,15 @@ static int __xen_pcibk_add_pci_dev(struct xen_pcibk_device *pdev,
 
 	mutex_lock(&vpci_dev->lock);
 
-	/* Keep multi-function devices together on the virtual PCI bus */
-	for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
-		if (!list_empty(&vpci_dev->dev_list[slot])) {
+	/*
+	 * Keep multi-function devices together on the virtual PCI bus, except
+	 * virtual functions.
+	 */
+	if (!dev->is_virtfn) {
+		for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
+			if (list_empty(&vpci_dev->dev_list[slot]))
+				continue;
+
 			t = list_entry(list_first(&vpci_dev->dev_list[slot]),
 				       struct pci_dev_entry, list);
 
@@ -116,7 +122,7 @@ static int __xen_pcibk_add_pci_dev(struct xen_pcibk_device *pdev,
 			       pci_name(dev), slot);
 			list_add_tail(&dev_entry->list,
 				      &vpci_dev->dev_list[slot]);
-			func = PCI_FUNC(dev->devfn);
+			func = dev->is_virtfn ? 0 : PCI_FUNC(dev->devfn);
 			goto unlock;
 		}
 	}
-- 
1.7.1