On Tue, Nov 22, 2016 at 04:41:37PM +0100, Borislav Petkov wrote: > 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? Or even modify them. Guests generally trust devices since they assume they are under their control. > > 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. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>