Re: [PATCH v2 1/7] KVM:VMX: Define CET VMCS fields and bits

[Jim Mattson]

On Tue, Jan 29, 2019 at 9:47 AM Jim Mattson <jmattson@xxxxxxxxxx> wrote:
>
> On Wed, Jan 23, 2019 at 6:06 AM Yang Weijiang <weijiang.yang@xxxxxxxxx> wrote:
> > Note: Although these VMCS fields are 64-bit, they don't have high fields.
>
> This statement directly contradicts the SDM, volume 3, appendix B.2:
>
> "A value of 1 in bits 14:13 of an encoding indicates a 64-bit field.
> There are 64-bit fields only for controls and for guest state. As
> noted in Section 24.11.2, every 64-bit field has two encodings, which
> differ on bit 0, the access type. Thus, each such field has an even
> encoding for full access and an odd encoding for high access."

Ah! They're not actually 64-bit fields. If you look at the encodings
(0x68XX and 0x6cxx), they're natural-width fields! Natural-width
fields don't have a high component.