Messages in this thread | | | Subject | Re: [PATCH v12 2/5] iommu: Enhance IOMMU default DMA mode build options | From | John Garry <> | Date | Mon, 14 Jun 2021 09:11:14 +0100 |
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On 12/06/2021 02:21, Lu Baolu wrote: > On 2021/6/11 20:20, John Garry wrote: >> +config IOMMU_DEFAULT_LAZY >> + bool "lazy" >> + help >> + Support lazy mode, where for every IOMMU DMA unmap operation, the >> + flush operation of IOTLB and the free operation of IOVA are >> deferred. >> + They are only guaranteed to be done before the related IOVA >> will be >> + reused. >> + >> + The isolation provided in this mode is not as secure as STRICT >> mode, >> + such that a vulnerable time window may be created between the DMA >> + unmap and the mapping finally being torn down in the IOMMU, >> where the >> + device can still access the system memory. However this mode may > > " ... and the mappings cached in the IOMMU IOTLB or device TLB finally > being invalidated, where the device probably can still access the memory > which has already been unmapped by the device driver."
ok, I can try to incorporate some of this wording.
As for this:
On 12/06/2021 03:12, Lu Baolu wrote: > On 2021/6/11 20:20, John Garry wrote: >> +choice >> + prompt "IOMMU default DMA mode" > > This is not explicit. > > How about > > "IOMMU DMA default cache invalidation policy" > > ? >
OK, but I'd rather use IOTLB, as that better matches the relevant iommu.c API name (iommu_ops.flush_iotlb_all).
Thanks, john
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