Commit 531353e6 authored by Robin Murphy's avatar Robin Murphy Committed by Joerg Roedel
Browse files

iommu: Update "iommu.strict" documentation 



Consolidating the flush queue logic also meant that the "iommu.strict"
option started taking effect on x86 as well. Make sure we document that.

Fixes: a250c23f ("iommu: remove DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE")
Signed-off-by: default avatarRobin Murphy <robin.murphy@arm.com>
Reviewed-by: default avatarLu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: default avatarJohn Garry <john.garry@huawei.com>
Link: https://lore.kernel.org/r/2c8c06e1b449d6b060c5bf9ad3b403cd142f405d.1623682646.git.robin.murphy@arm.com


Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
parent e86b041f

Documentation/admin-guide/kernel-parameters.txt

+5 −1
Original line number Diff line number Diff line
@@ -1987,7 +1987,7 @@ 
			  forcing Dual Address Cycle for PCI cards supporting

			  greater than 32-bit addressing.



	iommu.strict=	[ARM64] Configure TLB invalidation behaviour

	iommu.strict=	[ARM64, X86] Configure TLB invalidation behaviour

			Format: { "0" | "1" }

			0 - Lazy mode.

			  Request that DMA unmap operations use deferred
@@ -1998,6 +1998,10 @@ 
			1 - Strict mode (default).

			  DMA unmap operations invalidate IOMMU hardware TLBs

			  synchronously.

			Note: on x86, the default behaviour depends on the

			equivalent driver-specific parameters, but a strict

			mode explicitly specified by either method takes

			precedence.



	iommu.passthrough=

			[ARM64, X86] Configure DMA to bypass the IOMMU by default.