TSC clocksource not available in nested guests
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
linux (Ubuntu) |
Fix Released
|
Undecided
|
Unassigned | ||
Xenial |
Fix Released
|
Medium
|
Heitor Alves de Siqueira | ||
Bionic |
Fix Released
|
Medium
|
Heitor Alves de Siqueira |
Bug Description
[Impact]
* TSC clocksource not available in nested guests
[Test Case]
* Spin up a nested Xenial/Bionic guest and check for 'tsc' at
/sys/
[Regression Potential]
* The regression potential is low. Upstream code still maintains this
behaviour of skipping calibration on guests, and tsc code verifies if
the frequency is known before registering the clocksource
* Patches were verified against the above test case, and also tested
with stress-ng in both nested and non-nested guest scenarios
[Fix]
* By applying the upstream commits [0] [1], we skip refined calibration and
register TSC as a clocksource directly if its frequency is known (via
MSR or CPUID)
* Cosmic onwards (kernel 4.18+) are already fixed
[0] For Xenial only - https:/
[1] https:/
Changed in linux (Ubuntu Xenial): | |
status: | New → Confirmed |
Changed in linux (Ubuntu Bionic): | |
status: | New → Confirmed |
Changed in linux (Ubuntu Xenial): | |
importance: | Undecided → Medium |
Changed in linux (Ubuntu Bionic): | |
importance: | Undecided → Medium |
tags: | added: sts |
description: | updated |
Changed in linux (Ubuntu): | |
status: | Incomplete → Fix Released |
Changed in linux (Ubuntu Xenial): | |
assignee: | nobody → Heitor R. Alves de Siqueira (halves) |
Changed in linux (Ubuntu Bionic): | |
assignee: | nobody → Heitor R. Alves de Siqueira (halves) |
Changed in linux (Ubuntu Bionic): | |
status: | Confirmed → Fix Committed |
Changed in linux (Ubuntu Xenial): | |
status: | Confirmed → Fix Committed |
This bug is missing log files that will aid in diagnosing the problem. While running an Ubuntu kernel (not a mainline or third-party kernel) please enter the following command in a terminal window:
apport-collect 1822821
and then change the status of the bug to 'Confirmed'.
If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.
This change has been made by an automated script, maintained by the Ubuntu Kernel Team.