Re: [PATCH 1/3] cxl/pci: Use the Device GPF DVSEC for restricted endpoints

[Jonathan Cameron <jic23@kernel.org>]

On Tue, 22 Sep 2026 18:00:11 +0800
Guixin Liu <kanie@linux.alibaba.com> wrote:

> cxl_gpf_get_dvsec() picks between the Port and the Device GPF DVSEC
> from the PCIe type of the given device, and only a plain endpoint
> counts as a device. A restricted CXL device is an endpoint too, but
> it falls into the port case and is probed for the Port GPF DVSEC
> instead of the Device GPF DVSEC.
> 
> On an RCD, dirty shutdown tracking therefore never arms: the DVSEC
> lookup in cxl_nvdimm_arm_dirty_shutdown_tracking() fails, the dirty
> shutdown count stays invalid, and the warning complains about a
> missing Port GPF DVSEC on a device.
> 
> Treat restricted endpoints as devices.
> 
> Fixes: 36aace15d9bd ("cxl/pci: Drop the parameter is_port of cxl_gpf_get_dvsec()")
> Cc: stable@vger.kernel.org
> Assisted-by: LLM
> Signed-off-by: Guixin Liu <kanie@linux.alibaba.com>
Not an area I ever really messed around with, but the description and
fix look valid to me. So a somewhat tentative.

Reviewed-by: Jonathan Cameron <jonathan.cameron@oss.qualcomm.com>

> ---
>  drivers/cxl/core/pci.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c
> index 9d807c1a002c..e31aad7a525a 100644
> --- a/drivers/cxl/core/pci.c
> +++ b/drivers/cxl/core/pci.c
> @@ -804,7 +804,8 @@ u16 cxl_gpf_get_dvsec(struct device *dev)
>  		return 0;
>  
>  	pdev = to_pci_dev(dev);
> -	if (pci_pcie_type(pdev) == PCI_EXP_TYPE_ENDPOINT)
> +	if (pci_pcie_type(pdev) == PCI_EXP_TYPE_ENDPOINT ||
> +	    is_cxl_restricted(pdev))
>  		is_port = false;
>  
>  	dvsec = pci_find_dvsec_capability(pdev, PCI_VENDOR_ID_CXL,