Re: [RFC PATCH 0/5] hw/arm/virt: Add support for user-creatable nested SMMUv3

[Nicolin Chen <nicolinc@nvidia.com>]

On Tue, Feb 04, 2025 at 06:49:15PM +0100, Eric Auger wrote:
> > In summary, we will have the following series:
> > 1) HWPT uAPI patches in backends/iommufd.c (Zhenzhong or Shameer)
> >    https://lore.kernel.org/qemu-devel/SJ0PR11MB6744943702EB5798EC9B3B9992E02@SJ0PR11MB6744.namprd11.prod.outlook.com/
> > 2) vIOMMU uAPI patches in backends/iommufd.c (I will rebase/send)

> for 1 and 2, are you taking about the "Add VIOMMU infrastructure support
> " series in Shameer's branch: private-smmuv3-nested-dev-rfc-v1.
> Sorry I may instead refer to NVidia or Intel's branch but I am not sure
> about the last ones.

That "vIOMMU infrastructure" is for 2, yes.

For 1, it's inside the Intel's series:
"cover-letter: intel_iommu: Enable stage-1 translation for passthrough device"

So, we need to extract them out and make it separately..

> > 3) vSMMUv3 patches for HW-acc/nesting (Hoping Don/you could take over)
> We can start sending it upstream assuming we have a decent test environment.
> 
> However in
> https://lore.kernel.org/all/329445b2f68a47269292aefb34584375@huawei.com/
> 
> Shameer suggested he may include it in his SMMU multi instance series.
> What do you both prefer?

Sure, I think it's good to include those patches, though I believe
we need to build a new shared branch as Shameer's branch might not
reflect the latest kernel uAPI header.

Here is a new branch on top of latest master tree (v9.2.50):
https://github.com/nicolinc/qemu/commits/wip/for_shameer_02042025

I took HWPT patches from Zhenzhong's series and rebased all related
changes from my tree. I did some sanity and it should work with RMR.

Shameer, would you please try this branch and then integrate your
series on top of the following series?
   cover-letter: Add HW accelerated nesting support for arm SMMUv3
   cover-letter: Add vIOMMU-based nesting infrastructure support
   cover-letter: Add HWPT-based nesting infrastructure support
Basically, just replace my old multi-instance series with yours, to
create a shared branch for all of us.

Eric, perhaps you can start to look at the these series. Even the
first two iommufd series are a bit of rough integrations :)

Thanks
Nicolin