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Date: Thu, 15 Jul 2010 16:45:34 +0200
From: Joerg Roedel <joro@8bytes.org>
Subject: Re: [Qemu-devel] Re: [RFC PATCH 4/7] ide: IOMMU support
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To: Anthony Liguori <anthony@codemonkey.ws>
Cc: avi@redhat.com, Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>, Paul Brook <paul@codesourcery.com>, kvm@vger.kernel.org, qemu-devel@nongnu.org

On Thu, Jul 15, 2010 at 07:45:06AM -0500, Anthony Liguori wrote:
> On 07/15/2010 04:10 AM, Joerg Roedel wrote:

>> If this means a seperate interface for device dma accesses and not fold
>> that functionality into the cpu_physical_memory* interface I agree too :-)
>>
> No.  PCI devices should never call cpu_physical_memory*.

Fully agreed.

> PCI devices should call pci_memory*.
>
> ISA devices should call isa_memory*.

This is a seperate interface. I like the idea and as you stated below it
has clear advantages, so lets go this way.

> All device memory accesses should go through their respective buses.   
> There can be multiple IOMMUs at different levels of the device  
> hierarchy.  If you don't provide bus-level memory access functions that  
> chain through the hierarchy, it's extremely difficult to implement all  
> the necessary hooks to perform the translations at different places.


		Joerg