cxl/region: Add a region sysfs interface for region lock status

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There are 3 scenarios that leads to a locked region:
1. A region is created on a root decoder with Fixed Device Confiuration
   attribute.
2. CXL_HDM_DECODER0_CTRL_LOCK.

Both 1 & 1 are well described in:
commit 2230c4bdc4 ("cxl: Add handling of locked CXL decoder")

3) Platform that has region creation with PRMT address translation always
   locks the region, regardless of the FIXED attribute or decoder ctrl bit.

Region locked means region destroy operations are not permitted. CXL
region driver returns -EPERM for region destroy operations.

Although the locked status of the corresponding root decoder implies the
region is also locked, exposing the region lock status directly to
userspace improves usability for users who may not be aware of this
relationship.

[ dj: Amended commit log with additional locking scenarios. ]

Signed-off-by: Li Ming <ming.li@zohomail.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Alejandro Lucero <alucerop@amd.com>
Reviewed-by: Alison Schofield <alison.schofield@intel.com>
Link: https://patch.msgid.link/20260401124951.1290041-1-ming.li@zohomail.com
Signed-off-by: Dave Jiang <dave.jiang@intel.com>

...

This commit is contained in:

Li Ming 2026-04-01 20:49:51 +08:00 • committed by Dave Jiang

parent 261a02b93d

commit d585bc86fb

2 changed files with 30 additions and 0 deletions

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13

Documentation/ABI/testing/sysfs-bus-cxl

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17

drivers/cxl/core/region.c

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