[PATCH v2] PCI: Do not attempt to set ExtTag for VFs

[Håkon Bugge]

The bit for enabling extended tags is Reserved and Preserved (RsvdP)
for VFs, according to PCIe r7.0 section 7.5.3.4 table 7.21.  Hence,
bail out early from pci_configure_extended_tags() if the device is a
VF.

Otherwise, we may see incorrect log messages such as:

	   kernel: pci 0000:af:00.2: enabling Extended Tags

(af:00.2 is a VF)

Fixes: 60db3a4d8cc9 ("PCI: Enable PCIe Extended Tags if supported")
Signed-off-by: Håkon Bugge <haakon.bugge@xxxxxxxxxx>

---

v1 -> v2: Added ref to PCIe spec
---
 drivers/pci/probe.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 0ce98e18b5a87..014017e15bcc8 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -2244,7 +2244,8 @@ int pci_configure_extended_tags(struct pci_dev *dev, void *ign)
 	u16 ctl;
 	int ret;
 
-	if (!pci_is_pcie(dev))
+	/* PCI_EXP_DEVCTL_EXT_TAG is RsvdP in VFs */
+	if (!pci_is_pcie(dev) || dev->is_virtfn)
 		return 0;
 
 	ret = pcie_capability_read_dword(dev, PCI_EXP_DEVCAP, &cap);
-- 
2.43.5