Re: [PATCH] acpi: apei: call into AER handling regardless of severity

From: Borislav Petkov <bp@suse.de>
To: Sinan Kaya <okaya@codeaurora.org>
Cc: "Baicar, Tyler" <tbaicar@codeaurora.org>,
	Tony Luck <tony.luck@intel.com>,
	rjw@rjwysocki.net, lenb@kernel.org, will.deacon@arm.com,
	james.morse@arm.com, prarit@redhat.com, punit.agrawal@arm.com,
	shiju.jose@huawei.com, andriy.shevchenko@linux.intel.com,
	linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org,
	Linux PCI <linux-pci@vger.kernel.org>,
	Huang Ying <ying.huang@intel.com>
Subject: Re: [PATCH] acpi: apei: call into AER handling regardless of severity
Date: Wed, 30 Aug 2017 17:16:01 +0200	[thread overview]
Message-ID: <20170830151601.ro5qt5272e2msevp@pd.tnic> (raw)
In-Reply-To: <b630fa5e-c24b-06f4-47da-bed53161e0b7@codeaurora.org>

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 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.

> 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?

-- 
Regards/Gruss,
    Boris.

SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
-- 