linux-kernel - Re: [PATCH v10 13/13] cxl: Disable HPA/SPA translation handlers for Normalized Addressing

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Message-ID: <20260114183321.000074f2@huawei.com>
Date: Wed, 14 Jan 2026 18:33:21 +0000
From: Jonathan Cameron <jonathan.cameron@...wei.com>
To: Dave Jiang <dave.jiang@...el.com>
CC: Robert Richter <rrichter@....com>, 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>,
	Davidlohr Bueso <dave@...olabs.net>, <linux-cxl@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>, Gregory Price <gourry@...rry.net>, "Fabio M.
 De Francesco" <fabio.m.de.francesco@...ux.intel.com>, Terry Bowman
	<terry.bowman@....com>, Joshua Hahn <joshua.hahnjy@...il.com>
Subject: Re: [PATCH v10 13/13] cxl: Disable HPA/SPA translation handlers for
 Normalized Addressing

On Wed, 14 Jan 2026 11:28:31 -0700
Dave Jiang <dave.jiang@...el.com> wrote:

> On 1/14/26 9:48 AM, Robert Richter wrote:
> > The root decoder provides the callbacks hpa_to_spa and spa_to_hpa to
> > perform Host Physical Address (HPA) and System Physical Address
> > translations, respectively. The callbacks are required to convert
> > addresses when HPA != SPA. XOR interleaving depends on this mechanism,
> > and the necessary handlers are implemented.
> > 
> > The translation handlers are used for poison injection
> > (trace_cxl_poison, cxl_poison_inject_fops) and error handling
> > (cxl_event_trace_record).
> > 
> > In AMD Zen5 systems with Normalized Addressing, endpoint addresses are
> > not SPAs, and translation handlers are required for these features to
> > function correctly.
> > 
> > Now, as ACPI PRM translation could be expensive in tracing or error
> > handling code paths, do not yet enable translations to avoid its
> > intensive use. Instead, disable those features which are used only for
> > debugging and enhanced logging.
> > 
> > Introduce the flag CXL_REGION_F_NORM_ADDR that indicates Normalized
> > Addressing for a region and use it to disable poison injection and DPA
> > to HPA conversion.
> > 
> > Note: Dropped unused CXL_DECODER_F_MASK macro.
> > 
> > Reviewed-by: Alison Schofield <alison.schofield@...el.com>
> > Signed-off-by: Robert Richter <rrichter@....com>  
> 
> As you mentioned commit log needs updating, otherwise
> Reviewed-by: Dave Jiang <dave.jiang@...el.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@...wei.com>

Just goes to show one should always refresh email even when half way through
reviewing a patch series :)

Jonathan