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

[Bjorn Helgaas <helgaas@kernel.org>]

On Wed, Nov 12, 2025 at 10:54:40AM +0100, Håkon Bugge wrote:
> 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>

Applied to pci/enumeration for v6.20, thanks!

> ---
> 
> 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
>