linux-kernel - Re: [PATCH v2] PCI/AER: Consolidate CXL, ACPI GHES and native AER reporting paths

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Message-ID: <20250424172809.GA492728@bhelgaas>
Date: Thu, 24 Apr 2025 12:28:09 -0500
From: Bjorn Helgaas <helgaas@...nel.org>
To: Karolina Stolarek <karolina.stolarek@...cle.com>,
	"Shen, Yijun" <Yijun.Shen@...l.com>
Cc: Bjorn Helgaas <bhelgaas@...gle.com>, linux-pci@...r.kernel.org,
	Jon Pan-Doh <pandoh@...gle.com>,
	Terry Bowman <terry.bowman@....com>, Len Brown <lenb@...nel.org>,
	James Morse <james.morse@....com>, Tony Luck <tony.luck@...el.com>,
	Borislav Petkov <bp@...en8.de>,
	Ben Cheatham <Benjamin.Cheatham@....com>,
	Ira Weiny <ira.weiny@...el.com>,
	Shuai Xue <xueshuai@...ux.alibaba.com>,
	Liu Xinpeng <liuxp11@...natelecom.cn>,
	Darren Hart <darren@...amperecomputing.com>,
	Dan Williams <dan.j.williams@...el.com>, linux-cxl@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] PCI/AER: Consolidate CXL, ACPI GHES and native AER
 reporting paths

[+to Yijun @Dell in case there's some testing opportunity, thread at
https://lore.kernel.org/r/81c040d54209627de2d8b150822636b415834c7f.1742900213.git.karolina.stolarek@oracle.com]

On Thu, Apr 24, 2025 at 11:01:11AM +0200, Karolina Stolarek wrote:
> On 23/04/2025 22:31, Bjorn Helgaas wrote:
> > On Wed, Apr 23, 2025 at 03:52:27PM +0200, Karolina Stolarek wrote:
> > > 
> > > I wasn't able to produce logs for the CXL path (that is, Restricted CXL
> > > Device, as CXL1.1 devices not supported by the driver due to a missing
> > > functionality; confirmed by Terry) and faced issues when trying to inject
> > > errors via GHES. Is the lack of logs a blocker for this patch? I tested
> > > other CXL scenarios and my changes didn't cause regression, as far as I
> > > know.
> > 
> > Yes, I do think we need to say something about the output format
> > changes.
> 
> I understand.
> 
> > I assume you're trying GHES on machines that actually do
> > firmware-first error handling, right?  I found several GHES logs by
> > searching the web for "APEI Generic Hardware Error Source" "PCIe
> > error".  The majority were Dell boxes.
> 
> The only way to inject GHES errors I'm aware of is Mauro's patch for
> qemu[1], so I went down the virtualization path. As for working with the
> actual hardware, I'd need to ask around and learn more about the platform.

I'd be surprised if the qemu firmware supports firmware-first
handling, so I wouldn't expect to be able to exercise this path that
way.  I think there are some bits in HEST and similar tables that tell
us about this, e.g., ACPI r6.5, sec 18.3.2.4.

Unfortunately there are some typos in the spec (FIRMWARE_FIRST,
FIRMWAREFIRST in 18.4), so it's a little hard to find all the
references.

It's a long shot, but I added Yijun as a Dell contact that who might
have a pointer to someone who could possibly test GHES logging on a
Dell box with and without your patch so we could have a concrete
comparison of the dmesg log differences.

> > If you can't produce actual logs for comparison, I think we can take
> > info from a sample log somebody has posted and synthesize what the
> > changes would be after this patch.
> 
> I also found some logs at some point, mostly from 2021 and 2023, but I felt
> bad about mocking up the messages and tried to produce actual logs. If I
> can't find a way to get this working in two weeks, I'll revisit this idea.
> 
> All the best,
> Karolina
> 
> -------------------------------------------------------------
> [1] - https://lore.kernel.org/lkml/76824dfc6bb5dd23a9f04607a907ac4ccf7cb147.1740653898.git.mchehab+huawei@kernel.org/