netdev - [PATCH v22 23/25] cxl: Avoid dax creation for accelerators

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Message-ID: <20251205115248.772945-24-alejandro.lucero-palau@amd.com>
Date: Fri, 5 Dec 2025 11:52:46 +0000
From: <alejandro.lucero-palau@....com>
To: <linux-cxl@...r.kernel.org>, <netdev@...r.kernel.org>,
	<dan.j.williams@...el.com>, <edward.cree@....com>, <davem@...emloft.net>,
	<kuba@...nel.org>, <pabeni@...hat.com>, <edumazet@...gle.com>,
	<dave.jiang@...el.com>
CC: Alejandro Lucero <alucerop@....com>, Jonathan Cameron
	<Jonathan.Cameron@...wei.com>, Davidlohr Bueso <daves@...olabs.net>, "Ben
 Cheatham" <benjamin.cheatham@....com>
Subject: [PATCH v22 23/25] cxl: Avoid dax creation for accelerators

From: Alejandro Lucero <alucerop@....com>

By definition a type2 cxl device will use the host managed memory for
specific functionality, therefore it should not be available to other
uses.

Signed-off-by: Alejandro Lucero <alucerop@....com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@...wei.com>
Reviewed-by: Davidlohr Bueso <daves@...olabs.net>
Reviewed-by: Dave Jiang <dave.jiang@...el.com>
Reviewed-by: Ben Cheatham <benjamin.cheatham@....com>
---
 drivers/cxl/core/region.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
index 694bb1e543cc..4d37561c07b2 100644
--- a/drivers/cxl/core/region.c
+++ b/drivers/cxl/core/region.c
@@ -4116,6 +4116,13 @@ static int cxl_region_probe(struct device *dev)
 	if (rc)
 		return rc;
 
+	/*
+	 * HDM-D[B] (device-memory) regions have accelerator specific usage.
+	 * Skip device-dax registration.
+	 */
+	if (cxlr->type == CXL_DECODER_DEVMEM)
+		return 0;
+
 	/*
 	 * From this point on any path that changes the region's state away from
 	 * CXL_CONFIG_COMMIT is also responsible for releasing the driver.
-- 
2.34.1