Messages in this thread | | | Date | Fri, 28 Jul 2023 09:25:23 -0300 | From | Jason Gunthorpe <> | Subject | Re: [PATCH v1 7/7] iommu/arm-smmu-v3: Move CD table to arm_smmu_master |
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On Fri, Jul 28, 2023 at 07:11:46PM +0800, Michael Shavit wrote: > On Fri, Jul 28, 2023 at 2:43 AM Jason Gunthorpe <jgg@nvidia.com> wrote: > > > Then you can put the free in a detach op once the CD table becomes > > empty and it behaves much like it already does. > > This turns out to be a bit tricky; the SMMU driver detaches the > currently attached domain whenever a new domain is attached with > attach_dev().
Oh, yeah, it is a bit quirky that way
> More generally, do we really want to be de-allocating > the table whenever we switch between an S1 domain and other domain > types that don't make use of the table (such as IDENTITY or NESTED)?
Probably.
> One solution is to defer the allocation to the first attach_op, but > only free when the master is freed (this patch's v1 behavior).
That seems reasonable, just don't allocate it at probe time since PASID is very rarely used.
Jason
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