Re: [PATCH v3 1/1] x86/tdx: Handle MWAIT, MONITOR and WBINVD

[Andy Lutomirski]

On Mon, Mar 29, 2021 at 4:42 PM Sean Christopherson <seanjc@xxxxxxxxxx> wrote:
>
> On Mon, Mar 29, 2021, Kuppuswamy, Sathyanarayanan wrote:
> >
> >
> > On 3/29/21 4:23 PM, Andy Lutomirski wrote:
> > >
> > > > On Mar 29, 2021, at 4:17 PM, Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx> wrote:
> > > >
> > > > In non-root TDX guest mode, MWAIT, MONITOR and WBINVD instructions
> > > > are not supported. So handle #VE due to these instructions
> > > > appropriately.
> > >
> > > Is there something I missed elsewhere in the code that checks CPL?
> > We don't check for CPL explicitly. But if we are reaching here, then we
> > executing these instructions with wrong CPL.
>
> No, if these instructions take a #VE then they were executed at CPL=0.  MONITOR
> and MWAIT will #UD without VM-Exit->#VE.  Same for WBINVD, s/#UD/#GP.

Dare I ask about XSETBV?