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

[Sean Christopherson]

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.