Re: [PATCH v2 1/1] x86/tdx: Handle MWAIT, MONITOR and WBINVD

[Kuppuswamy, Sathyanarayanan]

On 3/29/21 3:12 PM, Dave Hansen wrote:
> On 3/29/21 3:09 PM, Kuppuswamy, Sathyanarayanan wrote:
> > > > > > +    case EXIT_REASON_MWAIT_INSTRUCTION:
> > > > > > +        /* MWAIT is supressed, not supposed to reach here. */
> > > > > > +        WARN(1, "MWAIT unexpected #VE Exception\n");
> > > > > > +        return -EFAULT;
> > > > >
> > > > > How is MWAIT "supppressed"?
> > > > I am clearing the MWAIT feature flag in early init code. We should also
> > > > disable this feature in firmware.
> > > > setup_clear_cpu_cap(X86_FEATURE_MWAIT);
> > >
> > > I'd be more explicit about that.  Maybe even reference the code that
> > > clears the X86_FEATURE.
> > This change is part of the same patch.
>
> Right, but if someone goes and looks at the switch() statement in 10
> years is it going to be obvious how MWAIT was "suppressed"?
Ok. I can add a comment line for it.
>

--
Sathyanarayanan Kuppuswamy
Linux Kernel Developer