Re: [PATCH] proc: added ept_ad flag to /proc/cpuinfo

From: Thomas Gleixner
Date: Fri Aug 03 2018 - 06:02:25 EST


On Thu, 2 Aug 2018, Peter Shier wrote:
> Thank you Thomas. I missed what I think is your fundamental point
> regarding duplication created by this patch between CPU feature bits
> and KVM's consumption of the IA32_VMX_EPT_VPID_CAP MSR.
> Should all the features in this MSR be exposed via CPU feature bits
> and should KVM consume only from there rather than reading the MSR
> directly? There are 16 feature bits in the MSR per SDM Vol 3d section
> A.10.

Uuurg. Probably not, unless they are important somehow for similar reasons
like the one you are exposing. I assume they are not, so using the MSR and
picking all bits directly from there is ok.

But thanks for taking a look as noew we at least know why it doesn't make
sense to convert VMX over as it has to read the MSR anyway.