Messages in this thread | | | Date | Thu, 4 Mar 2021 13:26:23 +0100 | From | Joerg Roedel <> | Subject | Re: [PATCH 2/5] iommu/vt-d: Remove WO permissions on second-level paging entries |
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On Thu, Feb 25, 2021 at 02:26:51PM +0800, Lu Baolu wrote: > When the first level page table is used for IOVA translation, it only > supports Read-Only and Read-Write permissions. The Write-Only permission > is not supported as the PRESENT bit (implying Read permission) should > always set. When using second level, we still give separate permissions > that allows WriteOnly which seems inconsistent and awkward. There is no > use case we can think off, hence remove that configuration to make it > consistent.
No use-case for WriteOnly mappings? How about DMA_FROM_DEVICE mappings?
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