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Date:   Fri, 15 Apr 2022 16:37:39 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     Jason Gunthorpe <jgg@nvidia.com>
Cc:     Christoph Hellwig <hch@lst.de>,
        Alex Williamson <alex.williamson@redhat.com>,
        Cornelia Huck <cohuck@redhat.com>, kvm@vger.kernel.org,
        Paolo Bonzini <pbonzini@redhat.com>,
        Eric Auger <eric.auger@redhat.com>, Yi Liu <yi.l.liu@intel.com>
Subject: Re: [PATCH 05/10] vfio: Move vfio_external_user_iommu_id() to
 vfio_file_ops
Message-ID: <20220415143739.GC1958@lst.de>
References: <0-v1-33906a626da1+16b0-vfio_kvm_no_group_jgg@nvidia.com> <5-v1-33906a626da1+16b0-vfio_kvm_no_group_jgg@nvidia.com> <20220415073125.GC24824@lst.de> <20220415122510.GJ2120790@nvidia.com>
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On Fri, Apr 15, 2022 at 09:25:10AM -0300, Jason Gunthorpe wrote:
> The PPC specific iommu_table_group is PPC's "drvdata" for the common
> struct iommu_group - it is obtained trivially by group->iommu_data
> 
> I think using iommu_group as the handle for it in common code is the
> right thing to do.
> 
> What I don't entirely understand is what is 'tablefd' doing in all
> this, or why the lookup of the kvmppc_spapr_tce_table is so
> weird. PPC's unique iommu uapi is still a mystery to me.

Yeah.  So I guess we should go with something like this patch for now.
Eventually as part of the actual iommufd work we'll need to unwind
the PPC stuff anyway.