Add split lock detection for EMR
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
linux (Ubuntu) |
Invalid
|
Medium
|
Unassigned | ||
Jammy |
Fix Released
|
Undecided
|
Roxana Nicolescu |
Bug Description
SRU Justification
[Impact]
Intel has introduced support for their new Emerald Rapids CPU.
It was backported to Jammy in #lp2015372
The remaining feature needed to fully support EMR is the split lock detection mechanism.
So far, bit 5 in IA32_CORE_
With more and more CPU models, this becomes hard to maintain. Moreover, the December 2022 edition of the Intel Instruction Set Extensions manual defined that the split lock disable bit in the IA32_CORE_
“All processors that enumerate support for MSR_IA32_CORE_CAPS and set MSR_IA32_
Thus, commit d7ce15e1d4162ab
“ x86/split_lock: Enumerate architectural split lock disable bit” from linux-next removes the need of adding a new CPU model in that mapping.
This is needed to support split lock detection for the new EMR CPU and future models that don’t suffer architectural changes.
[Testing]
Kernel was built on cbd and boot tested on a VM.
Intel was asked to install and test the new kernel from this ppa https:/
[Regression potential]
Very low, it is a small refactor and in essence, it does the exact same thing for existing cpu models:
1. For Icelake which does not have IA32_CORE_
2. For the rest, it automatically checks bit 5 of IA32_CORE_
Changed in linux (Ubuntu): | |
status: | Incomplete → Confirmed |
Changed in linux (Ubuntu Jammy): | |
status: | Incomplete → Confirmed |
description: | updated |
Changed in linux (Ubuntu): | |
status: | Confirmed → In Progress |
Changed in linux (Ubuntu Jammy): | |
status: | Confirmed → Fix Committed |
Changed in linux (Ubuntu): | |
status: | In Progress → Fix Committed |
status: | Fix Committed → Invalid |
Changed in linux (Ubuntu Jammy): | |
assignee: | nobody → Roxana Nicolescu (roxanan) |
Changed in linux (Ubuntu): | |
assignee: | Roxana Nicolescu (roxanan) → nobody |
tags: |
added: verification-done-jammy removed: verification-needed-jammy |
tags: |
added: verification-done-focal removed: verification-needed-focal |
Waiting on intel response if these 2 commits
- b041b525dab95
- 727209376f499
are needed to support this as well.