[PATCH v8 10/10] Documentation/ABI: Document CXL Reset PCI reset method

From: Srirangan Madhavan

Date: Fri Jul 03 2026 - 18:10:15 EST


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@xxxxxxxxxx>
---
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@xxxxxxxxxx>
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