-config IOMMU_DEFAULT_PASSTHROUGH
- bool "IOMMU passthrough by default"
+choice
+ prompt "IOMMU default DMA mode"
depends on IOMMU_API
- help
- Enable passthrough by default, removing the need to pass in
- iommu.passthrough=on or iommu=pt through command line. If this
- is enabled, you can still disable with iommu.passthrough=off
- or iommu=nopt depending on the architecture.
+ default IOMMU_DEFAULT_STRICT
+ help
+ This option allows IOMMU DMA mode to be chose at build time, to
As before:
/s/chose/chosen/, /s/allows IOMMU/allows an IOMMU/
I'm sorry that the previous version was not modified.
+ override the default DMA mode of each ARCHs, removing the need to
Again, as before:
ARCHs should be singular
OK
+ pass in kernel parameters through command line. You can still use
+ ARCHs specific boot options to override this option again.
*
+
+config IOMMU_DEFAULT_PASSTHROUGH
+ bool "passthrough"
+ help
+ In this mode, the DMA access through IOMMU without any addresses
+ translation. That means, the wrong or illegal DMA access can not
+ be caught, no error information will be reported.
If unsure, say N here.
+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.
why no advisory on how to set if unsure?
Because the LAZY and STRICT have their own advantages and disadvantages.
Should I say: If unsure, keep the default。
Maybe. So you could put this in the help for the choice, * above, and
remove the advisory on IOMMU_DEFAULT_PASSTHROUGH.
However the maintainer may have a different view.
Thanks,
John
+
+config IOMMU_DEFAULT_STRICT
+ bool "strict"
+ help
+ For every IOMMU DMA unmap operation, the flush operation of IOTLB and
+ the free operation of IOVA are guaranteed to be done in the unmap
+ function.
+
+ This mode is safer than the two above, but it maybe slower in some
+ high performace scenarios.
and here?
