group.of.nepali.translators team mailing list archive

["Heitor R. Alves de Siqueira" <1822821@xxxxxxxxxxxxxxxxxx>]

** Changed in: linux (Ubuntu)
       Status: Incomplete => Fix Released

-- 
You received this bug notification because you are a member of नेपाली
भाषा समायोजकहरुको समूह, which is subscribed to Xenial.
Matching subscriptions: Ubuntu 16.04 Bugs
https://bugs.launchpad.net/bugs/1822821

Title:
  TSC clocksource not available in nested guests

Status in linux package in Ubuntu:
  Fix Released
Status in linux source package in Xenial:
  Confirmed
Status in linux source package in Bionic:
  Confirmed

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/devices/system/clocksource/clocksource0/available_clocksource

  [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://git.kernel.org/linus/47c95a46d0f
  [1] https://git.kernel.org/linus/e10f78050323

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1822821/+subscriptions