[PATCH 6.6 109/283] PCI: Do not attempt to set ExtTag for VFs

Sasha Levin
2026-02-28T18:08:39Z

From: Håkon Bugge <haakon.bugge@oracle.com>

[ Upstream commit 73711730a1128d91ebca1a6994ceeb18f36cb0cd ]

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
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 5557290b63dc1..9b277a91d0cb4 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -2101,7 +2101,8 @@ 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);
--
2.51.0