Re: [PATCH v4 12/26] KVM: x86: Move TSC fixup logic to KVM arch resume callback

[Chao Gao]

On Thu, Sep 08, 2022 at 04:25:28PM -0700, isaku.yamahata@xxxxxxxxx wrote:
>From: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
>
>commit 0dd6a6edb012 ("KVM: Dont mark TSC unstable due to S4 suspend") made
>use of kvm_arch_hardware_enable() callback to detect that TSC goes backward
>due to S4 suspend.  It has to check it only when resuming from S4. Not
>every time virtualization hardware ennoblement.  Move the logic to
>kvm_arch_resume() callback.

IIUC, kvm_arch_resume() is called on the first CPU waking up from suspension.
But the detection was done on every CPU. Is it a problem (i.e., we fail to
detect TSC goes backward on some CPUs)?