Re: [PATCH v2 1/4] PCI/AER: Store more information in aer_err_info

From: Bjorn Helgaas <helgaas@kernel.org>
To: "Wang, Qingshun" <qingshun.wang@linux.intel.com>
Cc: linux-pci@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
	linux-acpi@vger.kernel.org, chao.p.peng@linux.intel.com,
	erwin.tsaur@intel.com, feiting.wanyan@intel.com,
	qingshun.wang@intel.com, "Rafael J. Wysocki" <rafael@kernel.org>,
	Len Brown <lenb@kernel.org>, James Morse <james.morse@arm.com>,
	Tony Luck <tony.luck@intel.com>, Borislav Petkov <bp@alien8.de>,
	Davidlohr Bueso <dave@stgolabs.net>,
	Jonathan Cameron <jonathan.cameron@huawei.com>,
	Dave Jiang <dave.jiang@intel.com>,
	Alison Schofield <alison.schofield@intel.com>,
	Vishal Verma <vishal.l.verma@intel.com>,
	Ira Weiny <ira.weiny@intel.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Mahesh J Salgaonkar <mahesh@linux.ibm.com>,
	Oliver O'Halloran <oohall@gmail.com>,
	Miaohe Lin <linmiaohe@huawei.com>,
	Shiju Jose <shiju.jose@huawei.com>,
	Adam Preble <adam.c.preble@intel.com>,
	Li Yang <leoyang.li@nxp.com>, Lukas Wunner <lukas@wunner.de>,
	Kuppuswamy Sathyanarayanan
	<sathyanarayanan.kuppuswamy@linux.intel.com>,
	Smita Koralahalli <Smita.KoralahalliChannabasappa@amd.com>,
	Robert Richter <rrichter@amd.com>,
	linux-kernel@vger.kernel.org, linux-cxl@vger.kernel.org,
	linux-edac@vger.kernel.org
Subject: Re: [PATCH v2 1/4] PCI/AER: Store more information in aer_err_info
Date: Tue, 6 Feb 2024 11:23:35 -0600	[thread overview]
Message-ID: <20240206172335.GA872811@bhelgaas> (raw)
In-Reply-To: <2rfnevhnhylik4r6smr56uunsxweo7s5elo65sjhiztvxnr6bq@5fcyv22zxyyp>

On Wed, Feb 07, 2024 at 12:41:41AM +0800, Wang, Qingshun wrote:
> On Mon, Feb 05, 2024 at 05:12:31PM -0600, Bjorn Helgaas wrote:
> > On Thu, Jan 25, 2024 at 02:27:59PM +0800, Wang, Qingshun wrote:
> > > When Advisory Non-Fatal errors are raised, both correctable and
> > > uncorrectable error statuses will be set. The current kernel code cannot
> > > store both statuses at the same time, thus failing to handle ANFE properly.
> > > In addition, to avoid clearing UEs that are not ANFE by accident, UE
> > > severity and Device Status also need to be recorded: any fatal UE cannot
> > > be ANFE, and if Fatal/Non-Fatal Error Detected is set in Device Status, do
> > > not take any assumption and let UE handler to clear UE status.
> > > 
> > > Store status and mask of both correctable and uncorrectable errors in
> > > aer_err_info. The severity of UEs and the values of the Device Status
> > > register are also recorded, which will be used to determine UEs that should
> > > be handled by the ANFE handler. Refactor the rest of the code to use
> > > cor/uncor_status and cor/uncor_mask fields instead of status and mask
> > > fields.
> > 
> > There's a lot going on in this patch.  Could it possibly be split up a
> > bit, e.g., first tease apart aer_err_info.status/.mask into
> > .cor_status/mask and .uncor_status/mask, then add .uncor_severity,
> > then add the device_status bit separately?  If it could be split up, I
> > think the ANFE case would be easier to see.
> 
> Thanks for the feedback! Will split it up into two pacthes in the next
> version.

Or even three:

  1) tease apart aer_err_info.status/.mask into .cor_status/mask and
     .uncor_status/mask

  2) add .uncor_severity

  3) add device_status

Looking at this again, I'm a little confused about 2) and 3).  I see
the new read of PCI_ERR_UNCOR_SEVER into .uncor_severity, but there's
no actual *use* of it.

Same for 3), I see the new read of PCI_EXP_DEVSTA, but AFAICS there's
no use of that value.

We should have the addition of these new values in the same patch
that *uses* them.

Bjorn