Re: [PATCH v9 04/16] PCI/AER: Dequeue forwarded CXL error

[Bowman, Terry]

On 6/10/2025 1:07 PM, Bowman, Terry wrote:
>
> On 6/9/2025 11:15 PM, Lukas Wunner wrote:
>> On Tue, Jun 03, 2025 at 12:22:27PM -0500, Terry Bowman wrote:
>>> --- a/drivers/cxl/core/ras.c
>>> +++ b/drivers/cxl/core/ras.c
>>> +static int cxl_rch_handle_error_iter(struct pci_dev *pdev, void *data)
>>> +{
>>> +	struct cxl_prot_error_info *err_info = data;
>>> +	struct pci_dev *pdev_ref __free(pci_dev_put) = pci_dev_get(pdev);
>>> +	struct cxl_dev_state *cxlds;
>>> +
>>> +	/*
>>> +	 * The capability, status, and control fields in Device 0,
>>> +	 * Function 0 DVSEC control the CXL functionality of the
>>> +	 * entire device (CXL 3.0, 8.1.3).
>>> +	 */
>>> +	if (pdev->devfn != PCI_DEVFN(0, 0))
>>> +		return 0;
>>> +
>>> +	/*
>>> +	 * CXL Memory Devices must have the 502h class code set (CXL
>>> +	 * 3.0, 8.1.12.1).
>>> +	 */
>>> +	if ((pdev->class >> 8) != PCI_CLASS_MEMORY_CXL)
>>> +		return 0;
>>> +
>>> +	if (!is_cxl_memdev(&pdev->dev) || !pdev->dev.driver)
>>> +		return 0;
>> Is the point of the "!pdev->dev.driver" check to ascertain that
>> pdev is bound to cxl_pci_driver?
>>
>> If so, you need to check "if (pdev->driver != &cxl_pci_driver)"
>> directly (like cxl_handle_cper_event() does).
>>
>> That's because there are drivers which may bind to *any* PCI device,
>> e.g. vfio_pci_driver.
>>
>> Thanks,
>>
>> Lukas
> Good point. I'm adding this change. Thanks Lukas.
>
> -Terry
Hi Lukas,

Looking closer to implement this change I find the cxl_pci_driver is defined static in cxl/pci.c and
is unavailable to reference in cxl/core/ras.c as-is. Would you like me to export cxl_pci_driver to
make available for this check? The existing class code check guarantees it is a CXL EP. Is it not
safe to expect it is bound to a the CXL driver?

-Terry