Re: [PATCH 1 of 6 V6] amd iommu: Add 2 hypercalls for libxc

[Wei Wang <wei.wang2@amd.com>]

On 03/12/2012 12:25 PM, Ian Jackson wrote:
> Wei Wang writes ("Re: [PATCH 1 of 6 V6] amd iommu: Add 2 hypercalls for libxc"):
>> The former one will be used by qemu. But Ian said we would not add new
>> features into qemu traditional,,So I am waiting for pci passthru patches
>> for upstream qemu being accepted and then I coudl send out my qemu
>> patch. I also had a prove-of-concept patch that was based on the old
>> qemu. I could rebase and resend it if necessary.
>>
>> http://lists.xen.org/archives/html/xen-devel/2011-12/msg01269.html
>
> How confident are we that the new hypercall will be needed for
> whatever shape of passthough support ends up in upstream qemu ?
>
> Ian.
>

Hi Ian,
Well, the hypercall itself is very simple and straightforward. It just 
allow qemu to notify Xen guest iommu msi configurations. Except this, 
there is also a need in qemu of registering a virtual iommu device in 
qemu bus. Since we might not wait upstream qemu for 4.2 release, I would 
like to suggest that if we could take the qemu patch back to traditional 
qemu. This will give Xen 4.2 the complete support for iommuv2 no matter 
how upstream qemu looks like, and will also help Linux distros that will 
be based on Xen 4.2 to have full iommuv2 support. How do you think about it?

Thanks,
Wei