Re: [PATCH v11 18/20] x86: Handle TDX erratum to reset TDX private memory during kexec() and reboot

[Peter Zijlstra]

On Tue, Jun 20, 2023 at 10:42:32AM +0000, Huang, Kai wrote:
> On Tue, 2023-06-20 at 10:11 +0200, Peter Zijlstra wrote:
> > On Mon, Jun 12, 2023 at 03:06:48AM +0000, Huang, Kai wrote:
> > 
> > > +       __mb();
> > 
> > __mb() is not a valid interface to use.
> 
> Thanks for feedback!
> 
> May I ask why, for education purpose? :)

it's the raw MFENCE wrapper, not one of the *many* documented barriers.

Also, typicaly you do *not* want MFENCE, MFENCE bad.