Messages in this thread | | | From | Michael Shavit <> | Date | Mon, 21 Aug 2023 17:31:23 +0800 | Subject | Re: [RFC PATCH v1 3/8] iommu/arm-smmu-v3-sva: Allocate new ASID from installed_smmus |
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On Fri, Aug 18, 2023 at 2:38 AM Jason Gunthorpe <jgg@nvidia.com> wrote: > > On Fri, Aug 18, 2023 at 02:16:25AM +0800, Michael Shavit wrote: > > Pick an ASID that is within the supported range of all SMMUs that the > > domain is installed to. > > > > Signed-off-by: Michael Shavit <mshavit@google.com> > > --- > > This seems like a pretty niche scenario, maybe we should just keep a > global for the max ASID? > > Otherwise we need a code to change the ASID, even for non-SVA domains, > when the domain is installed in different devices if the current ASID > is over the instance max..
This RFC took the other easy way out for this problem by rejecting attaching a domain if its currently assigned ASID/VMID is out of range when attaching to a new SMMU. But I'm not sure which of the two options is the right trade-off. Especially if we move VMID to a global allocator (which I plan to add for v2), setting a global maximum for VMID of 256 sounds small.
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