Re: [PATCH 2/2] KVM: x86: Forbid KVM_SET_CPUID{,2} after KVM_RUN

[Paolo Bonzini]

On 1/7/22 10:02, Vitaly Kuznetsov wrote:
> I'm again leaning towards an allowlist and currently I see only two
> candidates:
>
> CPUID.01H.EBX bits 31:24 (initial LAPIC id)
> CPUID.0BH.EDX (x2APIC id)
>
> Anything else I'm missing?

I would also ignore completely CPUID leaves 03H, 04H, 0BH, 80000005h, 
80000006h, 8000001Dh, 8000001Eh (cache and processor topology), just to 
err on the safe side.

We could change kvm_find_cpuid_entry to WARN if any of those leaves are 
passed.

Paolo