** Description changed:
- Description:
+ [Impact]
+
+ s390/topology: Use zero-based numbering for containing entities
+
+ Start the numbering scheme for higher-level topology structures (like
+ socket, book, drawer) at zero, matching the convention for other hardware
+ identifiers like e.g. CPU numbers.
+
+ Hardware documentation, the Hardware Management Console and other tools
+ like zmemtopo also use zero-based numbering for these containing entities.
+ Aligning the numbering in sysfs, procfs, and tools like lscpu improves
+ user experience by making it easier to correlate topology information
+ across different interfaces.
+
+ If available, Linux on s390 derives this physical topology information from
+ the stsi function code 15 store_topology instruction, which is defined to
+ start at 1 for the lowest numbered container id. Subtract one, so
+ drawer_id, book_id and socket_id in cpu_topology[] start with 0 for the
+ lowest numbered entity; and /proc/cpuinfo and tools like 'lscpu -ye'
+ display the expected values.
+
+ Display only, no functional change intended.
+
+ [Fix]
+
+ Cherry pick commit:
+ - 540f4a4f6ef8 ("s390/topology: Use zero-based numbering for containing
entities")
+
+ [Test Plan]
+
+ Run 'lscpu -ye' to make sure that zero-based numbering is used for
+ socket, book, drawer, etc.
+
+ [Regression Potential]
+
+ No functional change intended.
+ Regression potential is very low.
+
+
+ ---
+
+ Description:
s390/topology: Use zero-based numbering
- Symptom:
+ Symptom:
Ids displayed by 'lscpu -ye' don't match HW Ids
- Problem:
+ Problem:
Hardware documentation, the Hardware Management Console and other tools like
zmemtopo use zero-based numbering for socket, book, drawer. But the linux
kernel displays one-based numbering in sysfs, procfs and lscpu.
- Reproduction:
+ Reproduction:
'lscpu -ye'
- Affected Distros:
+ Affected Distros:
Ubuntu 22.04, 24.04, 26.04
- Solution:
+ Solution:
Correct the indices the kernel gets from HW sysinfo.
- Upstream-ID:
+ Upstream-ID:
540f4a4f6ef806a28e794001bb4beac4840a6090
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https://bugs.launchpad.net/bugs/2164516
Title:
[UBUNTU 22.04] s390/topology: Use zero-based numbering
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