Re: [PATCH v3 3/4] KVM: x86: Virtualize AMD CPUID faulting

[Christian Ludloff]

> It appears it was a deliberate decision, due in part to the fact that the traditional flow of checking CPL exceptions before intercepts typically applies to using instructions in an illegal way, but the user is not doing anything illegal here by executing CPUID which is normally a legal instruction at CPL3.
>
> That said, clearly the behavior is different now between the vendors, however at this point the feedback I got is that our architects want to stick with the existing behavior unless there is a strong reason that it is a problem for SW.

What is a HV expected to do for such a CPUID guest exit?

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C.