** Changed in: linux (Ubuntu Jammy)
Status: New => In Progress
** Changed in: linux (Ubuntu Noble)
Status: New => In Progress
** Changed in: ubuntu-z-systems
Status: New => In Progress
** Description changed:
+ SRU Justification:
+
+ [ Impact ]
+
+ * The CPU Measurement Facility (CPU MF) crypto counter set
+ is not listed in the device sysfs tree - it's not exported
+ in the sysfs directory /sys/devices/cpum_cf/events.
+
+ * The attribute files for each CPU-MF counter defined
+ in the crypto counter set is missing.
+
+ * This is caused by the counter second version number of CPU MF
+ hardware being incremented on new machines.
+
+ * This causes a sanity check to fail,
+ but the counters are supported by hardware.
+
+ * The solution is to remove the upper limit in counter second
+ version number check.
+
+ [ Fix ]
+
+ * f10933cbd2df f10933cbd2dfddf6273698a45f76db9bafd8150f "s390/cpum_cf:
+ make crypto counters upward compatible across machine types"
+
+ * The fix was upstream accepted with kernel v6.10(-rc1).
+
+ [ Test Plan ]
+
+ * Run the following commands on a new machine generation:
+ (hence only doable by IBM)
+ # ls -l /sys/devices/cpum_cf/events/ | grep AES
+
+ * If the output is empty than this patch is required.
+
+ * With a patched kernel the output should be like:
+ # ls /sys/devices/cpum_cf/events/ | grep AES
+ AES_BLOCKED_CYCLES
+ AES_BLOCKED_FUNCTIONS
+ AES_CYCLES
+ AES_FUNCTIONS
+
+ [ Where problems could occur ]
+
+ * This affects s390x only - CPU MF is s390-specific,
+ and only s390 specific code is modified.
+
+ * And it furthermore is limited to the crypto counter set
+ of CPU MF.
+
+ * So any impact is likely limited to hardware crypto counters
+ on s390x only.
+
+ * In s390/kernel/perf_cpum_cf.c the else if case got changed from
+ explicitly checking for 6 or 7 to >= 6 which seems to require
+ attention for future 8 and more cases.
+
+ * In s390/kernel/perf_cpum_cf_events.c the switch (ci.csvn) statement
+ was changed to an if / else if with similar logic.
+ Again attentioin for any potential future cases >= 8.
+
+ * It does not look like currently used cases (1..5 and 6..7)
+ are affected by the modification, just >7.
+
+ * Test build of patched jammy and noble s390x kernels were build
+ and are avaiable here:
+ https://launchpad.net/~fheimes/+archive/ubuntu/lp2074380
+
+ [ Other Info ]
+
+ * Since the code/fix was upstream accepted with kernel v6.10(-rc1)
+ it does not affect the current development release oracular.
+
+ * This SRU can also be seen under the umbrella of new
+ hardware enablement.
+
+ * Since it requires special hw, the verification needs to be
+ done by IBM.
+
+ __________
+
Description: kernel: s390/cpum_cf: make crypto counters upward
compatible
Symptom: The CPU Measurement facility crypto counter set is not
- listed in the device sysfs tree.
+ listed in the device sysfs tree.
Problem: The CPU Measurement facility crypto counter set is not
- exported in the sysfs directory
- /sys/devices/cpum_cf/events.
- The attribute files for each CPU-MF counter defined
- in the crypto counter set is missing. This is caused
- by the counter second version number of the CPU
- Measurement Facility hardware being incremented on
- new machines. This causes a sanity check to fail,
- but the counters are supported by hardware.
+ exported in the sysfs directory
+ /sys/devices/cpum_cf/events.
+ The attribute files for each CPU-MF counter defined
+ in the crypto counter set is missing. This is caused
+ by the counter second version number of the CPU
+ Measurement Facility hardware being incremented on
+ new machines. This causes a sanity check to fail,
+ but the counters are supported by hardware.
Solution: Remove upper limit in counter second version number
- check.
+ check.
Reproduction: Run command on a new machine generation:
- # ls -l /sys/devices/cpum_cf/events/ | grep AES
- #
- If the output is empty than this patch is required.
- The output should be:
- # ls /sys/devices/cpum_cf/events/ | grep AES
- AES_BLOCKED_CYCLES
- AES_BLOCKED_FUNCTIONS
- AES_CYCLES
- AES_FUNCTIONS
- #
+ # ls -l /sys/devices/cpum_cf/events/ | grep AES
+ #
+ If the output is empty than this patch is required.
+ The output should be:
+ # ls /sys/devices/cpum_cf/events/ | grep AES
+ AES_BLOCKED_CYCLES
+ AES_BLOCKED_FUNCTIONS
+ AES_CYCLES
+ AES_FUNCTIONS
+ #
Upstream-ID of fix: f10933cbd2dfddf6273698a45f76db9bafd8150f
** Changed in: linux (Ubuntu Jammy)
Assignee: (unassigned) => Frank Heimes (fheimes)
** Changed in: linux (Ubuntu Noble)
Assignee: (unassigned) => Frank Heimes (fheimes)
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https://bugs.launchpad.net/bugs/2074380
Title:
[UBUNTU 22.04] kernel: s390/cpum_cf: make crypto counters upward
compatible
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