Re: [PATCH v6 00/10] iommufd: Add vIOMMU infrastructure (Part-2: vDEVICE)

[Nicolin Chen <nicolinc@nvidia.com>]

On Thu, Oct 31, 2024 at 02:28:12PM +0800, Zhangfei Gao wrote:
> On Thu, 31 Oct 2024 at 05:36, Nicolin Chen <nicolinc@nvidia.com> wrote:
> >
> > Following the previous vIOMMU series, this adds another vDEVICE structure,
> > representing the association from an iommufd_device to an iommufd_viommu.
> > This gives the whole architecture a new "v" layer:
> >   _______________________________________________________________________
> >  |                      iommufd (with vIOMMU/vDEVICE)                    |
> >  |                        _____________      _____________               |
> >  |                       |             |    |             |              |
> >  |      |----------------|    vIOMMU   |<---|   vDEVICE   |<------|      |
> >  |      |                |             |    |_____________|       |      |
> >  |      |     ______     |             |     _____________     ___|____  |
> >  |      |    |      |    |             |    |             |   |        | |
> >  |      |    | IOAS |<---|(HWPT_PAGING)|<---| HWPT_NESTED |<--| DEVICE | |
> >  |      |    |______|    |_____________|    |_____________|   |________| |
> >  |______|________|______________|__________________|_______________|_____|
> >         |        |              |                  |               |
> >   ______v_____   |        ______v_____       ______v_____       ___v__
> >  |   struct   |  |  PFN  |  (paging)  |     |  (nested)  |     |struct|
> >  |iommu_device|  |------>|iommu_domain|<----|iommu_domain|<----|device|
> >  |____________|   storage|____________|     |____________|     |______|
> >
> > This vDEVICE object is used to collect and store all vIOMMU-related device
> > information/attributes in a VM. As an initial series for vDEVICE, add only
> > the virt_id to the vDEVICE, which is a vIOMMU specific device ID in a VM:
> > e.g. vSID of ARM SMMUv3, vDeviceID of AMD IOMMU, and vRID of Intel VT-d to
> > a Context Table. This virt_id helps IOMMU drivers to link the vID to a pID
> > of the device against the physical IOMMU instance. This is essential for a
> > vIOMMU-based invalidation, where the request contains a device's vID for a
> > device cache flush, e.g. ATC invalidation.
> >
> > Therefore, with this vDEVICE object, support a vIOMMU-based invalidation,
> > by reusing IOMMUFD_CMD_HWPT_INVALIDATE for a vIOMMU object to flush cache
> > with a given driver data.
> >
> > As for the implementation of the series, add driver support in ARM SMMUv3
> > for a real world use case.
> >
> > This series is on Github:
> > https://github.com/nicolinc/iommufd/commits/iommufd_viommu_p2-v6
> > (QEMU branch for testing will be provided in Jason's nesting series)
> 
> Thanks Nico
> 
> I tested on aarch64, functions are OK.
> 
> But with some hacks
> https://github.com/Linaro/linux-kernel-uadk/commit/22f47d6f3a34a0867a187473bd5ba0e0ee3395d4

Though we will have some small changes to this two series (and
possibly a small change to SMMUv3 driver too for that flags in
the hacks), would you mind giving this two series a Tested-by?

Thanks!
Nicolin