Date: Mon, 1 Dec 2008 18:27:50 +0100
From: Joerg Roedel <joerg.roedel@amd.com>
To: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
CC: avi@redhat.com, kvm@vger.kernel.org, weidong.han@intel.com,
       linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
       mingo@redhat.com, amit.shah@redhat.com
Subject: Re: [PATCH 3/9] add frontend implementation for the IOMMU API
Message-ID: <20081201172750.GD12816@amd.com>
References: <20081201231852P.fujita.tomonori@lab.ntt.co.jp> <20081201142727.GL29705@8bytes.org> <4933F5A7.8020408@redhat.com> <20081202005830P.fujita.tomonori@lab.ntt.co.jp>
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On Tue, Dec 02, 2008 at 12:58:29AM +0900, FUJITA Tomonori wrote:
> On Mon, 01 Dec 2008 16:33:11 +0200
> Avi Kivity <avi@redhat.com> wrote:
> 
> > Joerg Roedel wrote:
> > > Hmm, is there any hardware IOMMU with which we can't emulate domains by
> > > partitioning the IO address space? This concept works for GART and
> > > Calgary.
> > >
> > >   
> > 
> > Is partitioning secure?  Domain X's user could program its hardware to 
> > dma to domain Y's addresses, zapping away Domain Y's user's memory.
> 
> It can't be secure. So what's the point to emulate the domain
> partitioning in many traditional hardware IOMMUs that doesn't support
> it.

Btw, if you use the k8-agp driver the GART space is already partitioned
today. So this concept is not entirely new.

Joerg

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