From mboxrd@z Thu Jan  1 00:00:00 1970
From: Anthony Liguori <anthony@codemonkey.ws>
Subject: Re: [RFC] [VTD][patch 2/3] vt-d support for pci
 passthrough: kvm-vtd-user.patch
Date: Tue, 06 May 2008 19:39:50 -0500
Message-ID: <4820FA56.8000200@codemonkey.ws>
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	<482034C0.90808@qumranet.com>
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Cc: Chris Wright <chrisw@redhat.com>,
	kvm-devel@lists.sourceforge.net,
	"Kay,  Allen M" <allen.m.kay@intel.com>,
	Ben-Ami Yassour1 <benami@il.ibm.com>
To: Avi Kivity <avi@qumranet.com>
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Avi Kivity wrote:
> Kay, Allen M wrote:
>   
>> Still todo: move vt.d to kvm-intel.ko module.
>>   
>>     
>
> Not sure it's the right thing to do. If we get the iommus abstracted 
> properly, we can rename vtd.c to dma.c and move it to virt/kvm/.
>
> The code is certainly a lot more about managing memory than anything vmx 
> specific. It's hardly x86 specific, even.
>   

Really, an external interface to KVM that allowed someone to query the 
GPA => PA mapping would suffice.  It should not fault in pages that 
aren't present and we should provide notifications for when the mapping 
changes for a given reason.  Userspace can enforce the requirement that 
memory remains present via mlock().  This allows us to implement a PV 
API for DMA registration without the IOMMU code having any particular 
knowledge of it.

Regards,

Anthony Liguori


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