Re: [RFC PATCH, x86]: Disable CPA cache flush for selfsnoop targets

[Andy Lutomirski]

On Mon, Jul 15, 2019 at 12:39 PM Andi Kleen <ak@xxxxxxxxxxxxxxx> wrote:
>
> > Right, we don't know where the PAT invocation comes from and whether they
> > are safe to omit flushing the cache. The module load code would be one
> > obvious candidate.
>
> Module load just changes the writable/executable status, right? That shouldn't
> need to flush in any case because it doesn't change the caching attributes.
>

Indeed.  module load should require a single TLB flush and no cache
flushes.  I don't think we're currently efficient enough to do it with
a single TLB flush, but we should be able to...