On 8/30/2017 11:16 AM, Borislav Petkov wrote:
> On Wed, Aug 30, 2017 at 10:05:44AM -0400, Sinan Kaya wrote:
>> Link reset is not the only recovery mechanism. In the case of nonfatal
>> errors, it is assumed that the endpoint CSR is still reachable.
>> Error is propagated the PCIe endpoint driver. Endpoint driver does a
>> re-initialization, we are back in business.
>
> I'm assuming that's broadcast_error_message()'s job.
>
That's right. Each driver provides an err_handler hook. broadcast function
calls these.
static struct pci_driver e1000_driver = {
..
.err_handler = &e1000_err_handler
};
struct pci_error_handlers {
...
pci_ers_result_t (*error_detected)(struct pci_dev *dev,
enum pci_channel_state error);
}
>> That's not true. The GHES code is changing the severity here before posting
>> to the AER driver in ghes_do_proc().
>>
>> if (gdata->flags & CPER_SEC_RESET)
>> aer_severity = AER_FATAL;
>
> You're missing the point that we would walk into that if branch *only* for
>
> if (sev == GHES_SEV_RECOVERABLE &&
> sec_sev == GHES_SEV_RECOVERABLE
>
> severities. So if you have an AER_FATAL error but ghes severities are
> not GHES_SEV_RECOVERABLE, nothing happens.
I see. We should probably try to do something only if GHES_SEV_CORRECTED or
GHES_SEV_RECOVERABLE.
If somebody wants to crash the system with GHES_SEV_PANIC, there is no point
in doing additional work.
>
>> No, AER ISR is not set up if firmware first is enabled.
>
> So then this is a major suckage. We do AER recovery on FF systems only
> for GHES_SEV_RECOVERABLE severity.
>
>> The behavior should match non firmware-first case ideally.
>>
>> 1. Print all correctable errors.
>> 2. Go to do_recovery for all uncorrectable errors including fatal and
>> non-fatal.
>>
>> This is also what AER driver does in the absence of firmware first via
>> handle_error_source().
>
> Yes, that makes sense.
>
> Which would mean that we'd call aer_recover_queue() regardless of GHES
> severity but we'd do recovery only if GHES_SEV_RECOVERABLE is set
> or CPER_SEC_RESET. I.e., we can communicate all that by setting the
> correct AER severity before calling aer_recover_queue(). And then call
> do_recovery() based on AER severity.
>
> Hmmm?
>
Sounds good. Do you still want to do PCIe recovery in the case of
GHES_SEV_PANIC or if some FW returns GHES_SEV_NO?
--
Sinan Kaya
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.
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