lkml.org 
[lkml]   [2019]   [Aug]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [RFC PATCH] virtio_ring: Use DMA API if guest memory is encrypted
On Sun, Aug 11, 2019 at 04:55:27AM -0400, Michael S. Tsirkin wrote:
> On Sun, Aug 11, 2019 at 07:56:07AM +0200, Christoph Hellwig wrote:
> > So we need a flag on the virtio device, exposed by the
> > hypervisor (or hardware for hw virtio devices) that says: hey, I'm real,
> > don't take a shortcut.
>
> The point here is that it's actually still not real. So we would still
> use a physical address. However Linux decides that it wants extra
> security by moving all data through the bounce buffer. The distinction
> made is that one can actually give device a physical address of the
> bounce buffer.

Sure. The problem is just that you keep piling hacks on top of hacks.
We need the per-device flag anyway to properly support hardware virtio
device in all circumstances. Instead of coming up with another ad-hoc
hack to force DMA uses implement that one proper bit and reuse it here.

\
 
 \ /
  Last update: 2019-08-12 14:16    [W:0.112 / U:17.944 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site