linux-kernel - Re: "invalid agent type: 1" in acpi/ghes, cper: Recognize and cache CXL Protocol errors

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Message-ID: <2937432.AOxP5AVGnv@fdefranc-mobl3>
Date: Thu, 24 Jul 2025 16:49:00 +0200
From: "Fabio M. De Francesco" <fabio.m.de.francesco@...ux.intel.com>
To: Smita Koralahalli <Smita.KoralahalliChannabasappa@....com>,
 Marc Herbert <marc.herbert@...ux.intel.com>
Cc: linux-efi@...r.kernel.org, linux-kernel@...r.kernel.org,
 linux-cxl@...r.kernel.org, Ard Biesheuvel <ardb@...nel.org>,
 Alison Schofield <alison.schofield@...el.com>,
 Vishal Verma <vishal.l.verma@...el.com>, Ira Weiny <ira.weiny@...el.com>,
 Dan Williams <dan.j.williams@...el.com>,
 Jonathan Cameron <Jonathan.Cameron@...wei.com>,
 Yazen Ghannam <yazen.ghannam@....com>, Terry Bowman <terry.bowman@....com>,
 Dave Jiang <dave.jiang@...el.com>, tony.luck@...el.com,
 Gregory Price <gourry@...rry.net>
Subject: Re: "invalid agent type: 1" in acpi/ghes,
 cper: Recognize and cache CXL Protocol errors

Hi Marc, Smita,

On Wednesday, July 23, 2025 9:13:34 AM Central European Summer Time Marc Herbert wrote:
> 
> On 2025-07-22 12:24, Marc Herbert wrote:
> > Hi Smita,
> > 
> >   The code below triggers the error "invalid agent type: 1" in Intel
> > validation (internal issue 15018133056)
> 
> The same test case also triggers the other, warning message "CXL CPER no
> device serial number".
> 
> I heard that "device" serial numbers are only for... devices and that
> even then it's not always mandatory. So maybe that other message should
> be downgraded from warning to the "info" level?
> 
> Marc
>

[skip]

> >> +
> >> +	if (prot_err->err_len != sizeof(struct cxl_ras_capability_regs)) {
> >> +		pr_err_ratelimited("CXL CPER invalid RAS Cap size (%u)\n",
> >> +				   prot_err->err_len);
> >> +		return;
> >> +	}
> >> +
> >> +	if (!(prot_err->valid_bits & PROT_ERR_VALID_SERIAL_NUMBER))
> >> +		pr_warn(FW_WARN "CXL CPER no device serial number\n");
> >> +

Maybe this test should be written on the line of the following snippet taken 
out from "ACPI: extlog: Trace CPER CXL Protocol Error Section".[1]

+
+	if ((prot_err->agent_type == RCD || prot_err->agent_type == DEVICE ||
+	     prot_err->agent_type == LD || prot_err->agent_type == FMLD) &&
+	    !(prot_err->valid_bits & PROT_ERR_VALID_SERIAL_NUMBER))
+		pr_warn_ratelimited(FW_WARN
+				    "CXL CPER no device serial number\n");
+

Thanks,

Fabio

[1] https://lore.kernel.org/linux-cxl/20250623145453.1046660-4-fabio.m.de.francesco@linux.intel.com/