Re: [Qemu-devel] [0/13] RFC: Guest visible IOMMU

[Wei Wang]

On 03/22/2012 03:14 AM, David Gibson wrote:
> Here's another version of my series implementing the nevessary
> framework for emulation of guest-visible IOMMUs.  I've incorporated
> the feedback from the last posting.  I'm fairly confident that
> preliminary patches 1-3 are ready to go in, the rest might still need
> more consideration.
>
> In particular, if anyone has thoughts on how to handle the case where
> an IOMMU mapping is invalidated by the guest where a qemu-side device
> currently has that piece of IOVA-space dma_memory_map()ed, I'd be
> interested to hear it.

Hi David,
I am Xen developer. Currently I am working on a hardware based iommu 
emulation for amd iommu v2 systems (we need this to enable iommuv2 
drivers in guest OS and therefore to passthroug gpgpu to hvm guest). In 
this work, only a virtual iommu device has to be registered on qemu bus 
and dma translations are still performed by iommu hardware. So I wonder 
if it is possible that I could integrate my work with yours. I had a 
proof-of-concept patch for qemu:

http://lists.xen.org/archives/html/xen-devel/2011-12/msg01269.html

my last post was:
http://lists.xen.org/archives/html/xen-devel/2012-03/msg00591.html

Thanks and looking forward to your thoughts
Wei