Validated on linux 4.4.0-147.173 from xenial-proposed: ubuntu@xenial-l2:~$ uname -r 4.4.0-147-generic
ubuntu@xenial-l2:~$ cat /sys/devices/system/clocksource/clocksource0/available_clocksource kvm-clock tsc hpet acpi_pm ubuntu@xenial-l2:~$ dmesg | grep -i tsc [ 0.000000] tsc: Detected 1997.765 MHz processor [ 1.705310] clocksource: tsc: mask: 0xffffffffffffffff max_cycles: 0x3997de66ec2, max_idle_ns: 881590642279 ns ** Tags removed: verification-needed-xenial ** Tags added: verification-done-xenial -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. 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: Fix Committed Status in linux source package in Bionic: Fix Committed 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 -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
