> -----Original Message-----
> From: Duan, Zhenzhong <[email protected]>
> Sent: 08 December 2025 10:08
> To: Shameer Kolothum <[email protected]>; qemu-
> [email protected]; [email protected]
> Cc: [email protected]; [email protected]; Jason Gunthorpe
> <[email protected]>; Nicolin Chen <[email protected]>; [email protected];
> [email protected]; Nathan Chen <[email protected]>; Matt Ochs
> <[email protected]>; [email protected]; [email protected];
> [email protected]; [email protected];
> [email protected]; Liu, Yi L <[email protected]>; Krishnakant Jaju
> <[email protected]>
> Subject: RE: [PATCH v6 00/33] hw/arm/virt: Add support for user-creatable
> accelerated SMMUv3
> 
> External email: Use caution opening links or attachments
> 
> 
> Hi Shameer,
> 
> >-----Original Message-----
> >From: Shameer Kolothum <[email protected]>
> >Subject: [PATCH v6 00/33] hw/arm/virt: Add support for user-creatable
> >accelerated SMMUv3
> >
> >Hi,
> >
> >Changes from v5:
> >
> >https://lore.kernel.org/qemu-devel/20251031105005.24618-1-
> skolothumtho
> >@nvidia.com/
> >
> > - Addressed feedback from v5 and picked up R-by tags. Thanks to all!
> > - The previously split out _DSM fix mini-series is now accepted [0].
> > - Improved documentation about the rationale behind the design choice of
> >   returning an address space aliased to the system address space for
> >   vfio-pci endpoint devices (patch #10).
> > - Added error propagation support for smmuv3_cmdq_consume() (patch
> >#13).
> > - Updated vSTE based HWPT installation to check the SMMU enabled case
> >   (patch #14).
> > - Introduced an optional callback to PCIIOMMUOps to retrieve the MSI
> >   doorbell GPA directly, allowing us to avoid unsafe page table walks for
> >   MSI translation in accelerated SMMUv3 cases (patch #16).
> > - GBPA-based vSTE update depends on Nicolin's kernel patch [1].
> > - VFIO/IOMMUFD has dependency on Zhenzhong's patches: 4/5/8 from the
> >   pass-through support series [2].
> >
> >PATCH organization:
> > 1–26: Enables accelerated SMMUv3 with features based on default QEMU
> >SMMUv3,
> >       including IORT RMR based MSI support.
> > 27–29: Adds options for specifying RIL, ATS, and OAS features.
> > 30–33: Adds PASID support, including VFIO changes.
> >
> >Tests:
> >Performed basic sanity tests on an NVIDIA GRACE platform with GPU
> >device assignments. A CUDA test application was used to verify the SVA use
> case.
> >Further tests are always welcome.
> 
> I see PASID capability is exposed to guest but no pasid attachment in this
> series.
> Was the nested hwpt attached to SID instead of pasid?

In ARM world there is no specific PASID attachment. ARM uses a Context
Descriptor (CD) table indexed by PASID(substream in ARM) which is owned by
Guest. Hence, no specific PASID attach handling is required in QEMU.

How was page fault
> handled in stage1?

If you meant PRI CAP that is not supported yet.

However, Zhangfei is maintaining a branch to add support for devices that 
supports
SMMUv3 STALL feature and handles S1 page fault.
https://github.com/Linaro/qemu/commits/master-smmuv3-accel-v6/

Thanks,
Shameer

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