Re: [PATCH 04/15] cxl/aer/pci: Add CXL PCIe port correctable error support in AER service driver

Terry Bowman
2024-10-16T17:18:12Z

Hi Jonathan,

On 10/16/24 11:22, Jonathan Cameron wrote:
> On Tue, 8 Oct 2024 17:16:46 -0500
> Terry Bowman <terry.bowman@amd.com> wrote:
>
>> The AER service driver currently does not manage CXL PCIe port
>> protocol errors reported by CXL root ports, CXL upstream switch ports,
>> and CXL downstream switch ports. Consequently, RAS protocol errors
>> from CXL PCIe port devices are not properly logged or handled.
>>
>> These errors are reported to the OS via the root port's AER correctable
>> and uncorrectable internal error fields. While the AER driver supports
>> handling downstream port protocol errors in restricted CXL host (RCH)
>> mode also known as CXL1.1, it lacks the same functionality for CXL
>> PCIe ports operating in virtual hierarchy (VH) mode, introduced in
>> CXL2.0.
>>
>> To address this gap, update the AER driver to handle CXL PCIe port
>> device protocol correctable errors (CE).
>>
>> The uncorrectable error handling (UCE) will be added in a future
>> patch.
>>
>> Make this update alongside the existing downstream port RCH error
>> handling logic, extending support to CXL PCIe ports in VH.
>>
>> Signed-off-by: Terry Bowman <terry.bowman@amd.com>
> Minor comments inline.
>
> J
>> ---
>> drivers/pci/pcie/aer.c | 54 +++++++++++++++++++++++++++++++++---------
>> 1 file changed, 43 insertions(+), 11 deletions(-)
>>
>> diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
>> index dc8b17999001..1c996287d4ce 100644
>> --- a/drivers/pci/pcie/aer.c
>> +++ b/drivers/pci/pcie/aer.c
>> @@ -40,6 +40,8 @@
>> #define AER_MAX_TYPEOF_COR_ERRS 16 /* as per PCI_ERR_COR_STATUS */
>> #define AER_MAX_TYPEOF_UNCOR_ERRS 27 /* as per PCI_ERR_UNCOR_STATUS*/
>>
>> +#define CXL_DVSEC_PORT_EXTENSIONS 3
>
> Duplicate of definition in drivers/cxl/cxlpci.h
>
> Maybe wrap it up in an is_cxl_port() or similar? Or just
> move that to a header both places can exercise.
>
>

Ok. I'll move the value '3' into the function call rather than use a #define.

>> +
>> struct aer_err_source {
>> u32 status; /* PCI_ERR_ROOT_STATUS */
>> u32 id; /* PCI_ERR_ROOT_ERR_SRC */
>> @@ -941,6 +943,17 @@ static bool find_source_device(struct pci_dev *parent,
>> return true;
>> }
>>
>> +static bool is_pcie_cxl_port(struct pci_dev *dev)
>> +{
>> + if ((pci_pcie_type(dev) != PCI_EXP_TYPE_ROOT_PORT) &&
>> + (pci_pcie_type(dev) != PCI_EXP_TYPE_UPSTREAM) &&
>> + (pci_pcie_type(dev) != PCI_EXP_TYPE_DOWNSTREAM))
>> + return false;
>> +
>> + return (!!pci_find_dvsec_capability(dev, PCI_VENDOR_ID_CXL,
>> + CXL_DVSEC_PORT_EXTENSIONS));
>
> No need for the !! it will return the same without that clamping to 1/0
> because any non 0 value is true.
>

Ok

Regards,
Terry
>> +}
>> +