Re: [PATCH v2 0/3] Remove iommu_group_remove_device() from fsl

On Tue, May 23, 2023 at 08:26:32AM +0200, Joerg Roedel wrote:

On Tue, May 16, 2023 at 09:35:25PM -0300, Jason Gunthorpe wrote:

quoted

With POWER SPAPR now having a real iommu driver and using the normal group
lifecycle stuff fixing FSL will leave only VFIO's no-iommu support as a
user for the iommu_group_add/remove_device() calls. This will help
simplify the understanding of what the core code should be doing for these
functions.

Fix FSL to not need to call iommu_group_remove_device() at all.

v2:
 - Change the approach to use driver_managed_dma
 - Really simplify fsl_pamu_device_group() and just put everything in one
   function
 - New patch to make missing OF properties a probe failure
v1: https://lore.kernel.org/r/0-v1-1421774b874b+167-ppc_device_group_jgg@nvidia.com (local)

Jason Gunthorpe (3):
  iommu/fsl: Always allocate a group for non-pci devices
  iommu/fsl: Move ENODEV to fsl_pamu_probe_device()
  iommu/fsl: Use driver_managed_dma to allow VFIO to work

 arch/powerpc/sysdev/fsl_pci.c   |   1 +
 drivers/iommu/fsl_pamu_domain.c | 123 +++++++++-----------------------
 2 files changed, 36 insertions(+), 88 deletions(-)

Any chance someone can test this on real hardware?

There isn't even a MAINTAINERS entry for this, and the git log looks
pretty dead for a long time. I tried to cc people who might care,
but I'm not so optimistic - unless Li says something.

I do feel good that if there is a problem and someone does come
forward it can be fixed up without a big trouble. Certainly without
going back to mis-using iommu_grou_add/remove_device..

Thanks,
Jason