On Thu, Aug 10, 2023 at 11:39 PM Jason Gunthorpe [off-list ref] wrote:

Actually, I don't think this even works as nothing on the PASID path
adds to the list that arm_smmu_write_ctx_desc_devices() iterates over ??

Then the remaining two calls:

arm_smmu_share_asid(struct mm_struct *mm, u16 asid)
        arm_smmu_write_ctx_desc_devices(smmu_domain, 0, cd);

        This is OK only if the sketchy assumption that the CD
        we extracted for a conflicting ASID is not asigned to a PASID.

static void arm_smmu_mm_release(struct mmu_notifier *mn, struct mm_struct *mm)
        arm_smmu_write_ctx_desc_devices(smmu_domain, mm->pasid, &quiet_cd);

        This doesn't work because we didn't add the master to the list
        during __arm_smmu_sva_bind and this path is expressly working
        on the PASID binds, not the RID binds.

Actually it is working on the RID attached domain (as returned by
iommu_get_domain_for_dev() at sva_bind time) not the SVA domain
here... The arm SVA implementation completely dismisses the SVA handle
(I also have a patch to fix this ;) .  Need to find the time to polish
and send out).

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