PCI: Do not attempt to set ExtTag for VFs

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@oracle.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Zhu Yanjun <yanjun.zhu@linux.dev>
Link: https://patch.msgid.link/20251112095442.1913258-1-haakon.bugge@oracle.com

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 41183aed8f5d94c514e9d1787107999acbba7c4f..86665658d70477eab149bf951ee898cf1df2221b 100644 (file)
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -2270,7 +2270,8 @@ 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);