Re: [PATCH v4 1/1] x86/tdx: Handle MWAIT, MONITOR and WBINVD

[Kuppuswamy, Sathyanarayanan]

On 3/31/21 3:11 PM, Dave Hansen wrote:
> On 3/31/21 3:06 PM, Sean Christopherson wrote:
> > I've no objection to a nice message in the #VE handler.  What I'm objecting to
> > is sanity checking the CPUID model provided by the TDX module.  If we don't
> > trust the TDX module to honor the spec, then there are a huge pile of things
> > that are far higher priority than MONITOR/MWAIT.
>
> In other words:  Don't muck with CPUID or the X86_FEATURE at all.  Don't
> check it to comply with the spec.  If something doesn't comply, we'll
> get a #VE at *SOME* point.  We don't need to do belt-and-suspenders
> programming here.
>
> That sounds sane to me.
But I think there are cases (like MCE) where SEAM does not disable them because
there will be future support for it. We should at-least suppress such features
in kernel.
>

--
Sathyanarayanan Kuppuswamy
Linux Kernel Developer