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SubjectRe: [PATCH v5 4/5] KVM: VMX: Allow direct access to MSR_IA32_SPEC_CTRL
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On 31/01/2018 15:54, Jim Mattson wrote:
> You seem to be making the assumption that there is one L2. What if
> there are 100 L2s, and only one has write-access to IA32_SPEC_CTRL? Or
> what if there once was such an L2, but it's been gone for months? The
> current mechanism penalizes *all* L2s if any L2, ever, has
> write-access to IA32_SPEC_CTRL.

Yes, but how would moving the field into struct loaded_vmcs do anything?
Only vmon/vmoff would change anything in vmx->nested.vmcs02.

Even then, L1 vmexits will also be penalized because L1 has probably
done an RDMSR/WRMSR on L2->L1 vmexit. So I don't think it's an issue?

Paolo

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