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RE: [Xen-devel] RE: information leaking between domains via granted page

To: "Keir Fraser" <keir.fraser@xxxxxxxxxxxxx>, "Santos, Jose Renato G" <joserenato.santos@xxxxxx>, <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: RE: [Xen-devel] RE: information leaking between domains via granted pages?
From: "James Harper" <james.harper@xxxxxxxxxxxxxxxx>
Date: Tue, 4 Mar 2008 19:53:09 +1100
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Thread-topic: [Xen-devel] RE: information leaking between domains via granted pages?
> > Maybe I'm mistaken about the way 'page flipping' on the rx path
works
> > then... care to enlighten me?
> 
> The flipping path is not high performance these days as we expect only
> very old domUs to use it. All skbuffs destined for a flipping
interface
> are laundered through netbk_copy_skb(). Note its judicious use of
> __GFP_ZERO.

Hmmm... I thought that flipping would be a high performance path?

So if we use rx-copy, does this mean that data is received from a
physical interface (or another domain) via DMA, and then actually copied
into the buffers for DomU? Do we consider the performance implications
of this too low to be worrying about?

Thanks

James


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