Messages in this thread | | | From | "Tian, Kevin" <> | Subject | RE: [RFC v16 1/9] iommu: Introduce attach/detach_pasid_table API | Date | Thu, 9 Dec 2021 03:59:57 +0000 |
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> From: Tian, Kevin > Sent: Thursday, December 9, 2021 10:58 AM > > For ARM it's SMMU's PASID table format. There is no step-2 since PASID > is already within the address space covered by the user PASID table. >
One correction here. 'no step-2' is definitely wrong here as it means more than user page table in your plan (e.g. dpdk).
To simplify it what I meant is:
iommufd reports how many 'user page tables' are supported given a device.
ARM always reports only one can be supported, and it must be created in PASID table format. tagged by RID.
Intel reports one in step1 (tagged by RID), and N in step2 (tagged by RID+PASID). A special flag in attach call allows the user to specify the additional PASID routing info for a 'user page table'.
Thanks Kevin
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