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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <20260108235447.GA520211@bhelgaas>
Date: Thu, 8 Jan 2026 17:54:47 -0600
From: Bjorn Helgaas <helgaas@...nel.org>
To: Håkon Bugge <haakon.bugge@...cle.com>
Cc: Bjorn Helgaas <bhelgaas@...gle.com>, Sinan Kaya <okaya@...eaurora.org>,
	linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] PCI: Do not attempt to set ExtTag for VFs

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@...cle.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
>