[libvirt-users] KVM guest incorrect CPU frequency

[xmbbb]

Hello,

I am facing an issue where the detected CPU frequencies in KVM guests are incorrect.

I am using the new Core i9 7900x with base clock 3.3GHz with "host-passthrough". Both Win10 and Linux guests incorrectly detect 3.45GHz for some reason.

The workaround I have found is to temporarily switch to use HPET clocksource in the HOST before starting the VM. This makes the VMs correctly detect a 3.3GHz CPU. Then I can safely switch back to TSC in the VM HOST.

This mostly does not impact much for day to day use. The only reproducible bug I can find with an incorrect CPU frequency is playing Bink videos that come with PC games. If I play any Bink video cut scene from the 2013 Tomb Raider game with the incorrect CPU frequency, the video plays a little slower than intended which results in audio cut out once in a while so that the video can "catch up" to the audio.

Anyone having experiences with similar issues?
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