Linux CXL
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From: Srirangan Madhavan <smadhavan@nvidia.com>
To: Alison Schofield <alison.schofield@intel.com>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Dan Williams <djbw@kernel.org>, Dave Jiang <dave.jiang@intel.com>,
	Davidlohr Bueso <dave@stgolabs.net>,
	Ira Weiny <ira.weiny@intel.com>,
	Jonathan Cameron <jic23@kernel.org>,
	Vishal Verma <vishal.l.verma@intel.com>,
	linux-cxl@vger.kernel.org, linux-pci@vger.kernel.org,
	linux-kernel@vger.kernel.org
Cc: Alex Williamson <alex.williamson@redhat.com>,
	vsethi@nvidia.com, alwilliamson@nvidia.com,
	Dan Williams <danwilliams@nvidia.com>,
	Sai Yashwanth Reddy Kancherla <skancherla@nvidia.com>,
	Vishal Aslot <vaslot@nvidia.com>,
	Manish Honap <mhonap@nvidia.com>, Jiandi An <jan@nvidia.com>,
	Richard Cheng <icheng@nvidia.com>,
	linux-tegra@vger.kernel.org,
	Srirangan Madhavan <smadhavan@nvidia.com>
Subject: [PATCH v8 10/10] Documentation/ABI: Document CXL Reset PCI reset method
Date: Fri,  3 Jul 2026 22:05:08 +0000	[thread overview]
Message-ID: <20260703220508.546528-11-smadhavan@nvidia.com> (raw)
In-Reply-To: <20260703220508.546528-1-smadhavan@nvidia.com>

Document the "cxl_reset" PCI reset_method value for Type 2 CXL devices.
CXL Reset is device scoped, requires affected memory to be idle,
invalidates CPU caches, restores cached HDM decoder state, and does not
request Memory Clear.

Signed-off-by: Srirangan Madhavan <smadhavan@nvidia.com>
---
 Documentation/ABI/testing/sysfs-bus-pci | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci
index b767db2c52cb..5ab46a4340ae 100644
--- a/Documentation/ABI/testing/sysfs-bus-pci
+++ b/Documentation/ABI/testing/sysfs-bus-pci
@@ -153,6 +153,20 @@ Description:
 		"default" enables all supported reset methods in the
 		default ordering.
 
+		If present, "cxl_reset" selects CXL Reset for CXL Type 2
+		devices that advertise CXL Reset support and whose reset scope is
+		limited to the selected PCI function.  The method is not listed
+		when CXL Reset would affect another CXL.cache or CXL.mem function.
+
+		Before issuing CXL Reset, the kernel quiesces the PCI function,
+		rejects the operation if cached HDM state is unavailable or
+		affected CXL memory is busy, invalidates CPU caches for enabled
+		HDM ranges, disables CXL.cache, and initiates cache write-back
+		where supported.  After reset, the kernel restores PCI config
+		state needed to access HDM MMIO, restores cached HDM decoder
+		state, and completes PCI reset recovery.  "cxl_reset" does not
+		request CXL Reset Memory Clear.
+
 What:		/sys/bus/pci/devices/.../reset
 Date:		July 2009
 Contact:	Michael S. Tsirkin <mst@redhat.com>
-- 
2.43.0


  parent reply	other threads:[~2026-07-03 22:05 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-07-03 22:04 [PATCH v8 00/10] PCI/CXL: Add CXL reset support for Type 2 devices Srirangan Madhavan
2026-07-03 22:04 ` [PATCH v8 01/10] cxl: Split decoder programming into a reusable helper Srirangan Madhavan
2026-07-07  0:22   ` Dave Jiang
2026-07-03 22:05 ` [PATCH v8 02/10] cxl: Cache decoder settings on PCI devices Srirangan Madhavan
2026-07-03 22:05 ` [PATCH v8 03/10] cxl: Share HDM decoder decode logic Srirangan Madhavan
2026-07-03 22:05 ` [PATCH v8 04/10] cxl: Cache endpoint decoder settings during PCI enumeration Srirangan Madhavan
2026-07-07  5:30   ` Richard Cheng
2026-07-03 22:05 ` [PATCH v8 05/10] cxl: Add CXL Device Reset helper Srirangan Madhavan
2026-07-03 22:05 ` [PATCH v8 06/10] cxl: Validate HDM ranges before CXL reset Srirangan Madhavan
2026-07-03 22:05 ` [PATCH v8 07/10] PCI/CXL: Discover the CXL reset scope Srirangan Madhavan
2026-07-07  1:45   ` Richard Cheng
2026-07-03 22:05 ` [PATCH v8 08/10] cxl: Restore CXL HDM state after PCI reset Srirangan Madhavan
2026-07-07  1:34   ` Richard Cheng
2026-07-03 22:05 ` [PATCH v8 09/10] PCI/CXL: Expose CXL Reset as a PCI reset method Srirangan Madhavan
2026-07-03 22:05 ` Srirangan Madhavan [this message]
2026-07-03 22:08 ` [PATCH RFC] PCI/CXL: Restore HDM state after CXL bus reset Srirangan Madhavan
2026-07-06 23:13 ` [PATCH v8 00/10] PCI/CXL: Add CXL reset support for Type 2 devices Dave Jiang
2026-07-07  5:41 ` Richard Cheng

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