Re: [RFC PATCH v3 13/20] x86: DMA support for memory encryption

[Borislav Petkov]

On Tue, Nov 22, 2016 at 05:22:38PM +0200, Michael S. Tsirkin wrote:
> The issue is it's a (potential) security hole, not a slowdown.

How? Because the bounce buffers will be unencrypted and someone might
intercept them?

> To disable unsecure things. If someone enables SEV one might have an
> expectation of security.  Might help push vendors to do the right thing
> as a side effect.

Ok, you're looking at the SEV-cloud-multiple-guests aspect. Right, that
makes sense.

I guess for SEV we should even flip the logic: disable such devices by
default and an opt-in option to enable them and issue a big fat warning.
I'd even want to let the guest users know that they're on a system which
cannot give them encrypted DMA to some devices...

-- 
Regards/Gruss,
    Boris.

Good mailing practices for 400: avoid top-posting and trim the reply.