Re: [RFC v2-fix-v2 2/2] x86/tdx: Ignore WBINVD instruction for TDX guest

[Andi Kleen]

 that.

> I thought we discussed that there are other considerations for wbinvd
> besides DMA? In any event this paragraph is actively misleading
> because it disregards ACPI and Persistent Memory secure-erase whose
> usages of wbinvd have nothing to do with DMA.


In this case they would be broken in KVM too.


> I would much prefer a
> patch to shutdown all the known wbinvd users as a precursor to this
> patch rather than assuming it's ok to simply ignore it. You have
> mentioned that TDX does not need to use those paths, but rather than
> assume they can't be used why not do the audit to explicitly disable
> them? Otherwise this statement seems to imply that the audit has not
> been done.

We're not assuming it. We know it because KVM does it since forever.

All we want to do is do the same as KVM.

-Andi