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

[Nicolin Chen <nicolinc@nvidia.com>]

On Fri, Jan 31, 2025 at 05:54:56PM +0100, Eric Auger wrote:
> On 1/9/25 5:45 AM, Nicolin Chen wrote:
> > On Mon, Dec 16, 2024 at 10:01:29AM +0000, Shameerali Kolothum Thodi wrote:
> >> And patches prior to this commit adds that support: 
> >> 4ccdbe3: ("cover-letter: Add HW accelerated nesting support for arm
> >> SMMUv3")
> >>
> >> Nicolin is soon going to send out those for review. Or I can include
> >> those in this series so that it gives a complete picture. Nicolin?
> > Just found that I forgot to reply this one...sorry
> >
> > I asked Don/Eric to take over that vSMMU series:
> > https://lore.kernel.org/qemu-devel/Zy0jiPItu8A3wNTL@Asurada-Nvidia/
> > (The majority of my effort has been still on the kernel side:
> >  previously vIOMMU/vDEVICE, and now vEVENTQ/MSI/vCMDQ..)
> >
> > Don/Eric, is there any update from your side?
> To be honest we have not much progressed so far. On my end I can
> dedicate some cycles now. I currently try to understand how and what
> subset I can respin and which test setup can be used. I will come back
> to you next week.

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)
3) vSMMUv3 patches for HW-acc/nesting (Hoping Don/you could take over)
4) Shameer's work on "-device" in ARM virt.c
5) vEVENTQ for fault injection (if time is right, squash into 2/3)

Perhaps, 3/4 would come in a different order, or maybe 4 could split
into a few patches changing "-device" (sending before 3) and then a
few other patches adding multi-vSMMU support (sending after 3).

My latest QEMU branch for reference:
https://github.com/nicolinc/qemu/commits/wip/for_iommufd_veventq-v6
It hasn't integrated Shameer's and Nathan's work though..
For testing, use this kernel branch:
https://github.com/nicolinc/iommufd/commits/iommufd_veventq-v6-with-rmr

I think we'd need to build a shared branch by integrating the latest
series in the list above.

Thanks
Nicolin