[Bug 205151] New: "user requested TSC rate below hardware speed" warning

[Bug 205151] New: "user requested TSC rate below hardware speed" warning

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=205151

            Bug ID: 205151
           Summary: "user requested TSC rate below hardware speed" warning
           Product: Virtualization
           Version: unspecified
    Kernel Version: 5.3
          Hardware: x86-64
                OS: Linux
              Tree: Mainline
            Status: NEW
          Severity: normal
          Priority: P1
         Component: kvm
          Assignee: virtualization_kvm@kernel-bugs.osdl.org
          Reporter: v.zubkov87@gmail.com
        Regression: Yes

5.3 seems to have broken TSC, at least for qemu/kvm VMs. After 5.3 upgrade
starting a VM gets me "user requested TSC rate below hardware speed" warnings
(1 per assigned core).

I'm not quite sure when kind of data I could provide, however after a short
while (several minutes) drift becomes quite noticable (severe audio/video
desync).

Relevant(?) dmesg entries from 5.3:
[Sun Oct  6 16:59:21 2019] tsc: Detected 4000.000 MHz processor
[Sun Oct  6 16:59:21 2019] tsc: Detected 3999.984 MHz TSC
[Sun Oct  6 16:59:22 2019] tsc: Refined TSC clocksource calibration: 4008.064
MHz
[Sun Oct  6 17:00:48 2019] user requested TSC rate below hardware speed
[Sun Oct  6 17:00:48 2019] user requested TSC rate below hardware speed

And 5.2:
[Thu Oct  3 21:56:01 2019] tsc: Detected 4000.000 MHz processor
[Thu Oct  3 21:56:01 2019] tsc: Detected 4008.000 MHz TSC
(no refined calibration here)

My CPU is Intel(R) Core(TM) i7-6700K CPU @ 4.00GHz (family: 0x6, model: 0x5e,
stepping: 0x3).

Revering commit 604dc9170f2435d27da5039a3efd757dceadc684 fixes the problem.

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