RE: [PATCH v5 00/27] Update SMMUv3 to the modern iommu API (part 2/3)

[Shameerali Kolothum Thodi <shameerali.kolothum.thodi@huawei.com>]

> -----Original Message-----
> From: Jason Gunthorpe <jgg@nvidia.com>
> Sent: Monday, March 4, 2024 11:44 PM
> To: iommu@lists.linux.dev; Joerg Roedel <joro@8bytes.org>; linux-arm-
> kernel@lists.infradead.org; Robin Murphy <robin.murphy@arm.com>; Will
> Deacon <will@kernel.org>
> Cc: Eric Auger <eric.auger@redhat.com>; Jean-Philippe Brucker <jean-
> philippe@linaro.org>; Moritz Fischer <mdf@kernel.org>; Michael Shavit
> <mshavit@google.com>; Nicolin Chen <nicolinc@nvidia.com>;
> patches@lists.linux.dev; Shameerali Kolothum Thodi
> <shameerali.kolothum.thodi@huawei.com>
> Subject: [PATCH v5 00/27] Update SMMUv3 to the modern iommu API (part 2/3)
> 
> Continuing the work of part 1 this focuses on the CD, PASID and SVA
> components:
> 
>  - attach_dev failure does not change the HW configuration.
> 
>  - Full PASID API support including:
>     - S1/SVA domains attached to PASIDs
>     - IDENTITY/BLOCKED/S1 attached to RID
>     - Change of the RID domain while PASIDs are attached
> 
>  - Streamlined SVA support using the core infrastructure
> 
>  - Hitless, whenever possible, change between two domains
> 
> Making the CD programming work like the new STE programming allows
> untangling some of the confusing SVA flows. From there the focus is on
> building out the core infrastructure for dealing with PASID and CD
> entries, then keeping track of unique SSID's for ATS invalidation.
> 
> The ATS ordering is generalized so that the PASID flow can use it and put
> into a form where it is fully hitless, whenever possible. Care is taken to
> ensure that ATC flushes are present after any change in translation.
> 
> Finally we simply kill the entire outdated SVA mmu_notifier implementation
> in one shot and switch it over to the newly created generic PASID & CD
> code. This avoids the messy and confusing approach of trying to
> incrementally untangle this in place. The new code is small and simple
> enough this is much better than trying to figure out smaller steps.
> 
> Once SVA is resting on the right CD code it is straightforward to make the
> PASID interface functionally complete.
> 
> It achieves the same goals as the several series from Michael and the S1DSS
> series from Nicolin that were trying to improve portions of the API.
> 
> This is on github:
> https://github.com/jgunthorpe/linux/commits/smmuv3_newapi


Performed few tests with this series on a HiSilicon D06 board(SMMUv3).

-Host kernel: boot with translated and passthrough cases.
-Host kernel: ACC dev SVA test run with uadk/uadk_tool benchmark.

With Qemu branch:
https://github.com/nicolinc/qemu/commits/wip/iommufd_vsmmu-02292024/

-Guest with a n/w VF dev, legacy VFIO mode.
-Guest with a n/w VF dev, IOMMUFD mode.
-Hot plug(add/del) on both VFIO and IOMMUFD modes.

All works as expected.

FWIW:
Tested-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>

Thanks,
Shameer