From 26225bea1d84b090b378838a1797daec62d4ad0e Mon Sep 17 00:00:00 2001 From: Robin Murphy Date: Wed, 11 Aug 2021 13:21:35 +0100 Subject: iommu: Expose DMA domain strictness via sysfs The sysfs interface for default domain types exists primarily so users can choose the performance/security tradeoff relevant to their own workload. As such, the choice between the policies for DMA domains fits perfectly as an additional point on that scale - downgrading a particular device from a strict default to non-strict may be enough to let it reach the desired level of performance, while still retaining more peace of mind than with a wide-open identity domain. Now that we've abstracted non-strict mode as a distinct type of DMA domain, allow it to be chosen through the user interface as well. Reviewed-by: Lu Baolu Reviewed-by: John Garry Signed-off-by: Robin Murphy Link: https://lore.kernel.org/r/0e08da5ed4069fd3473cfbadda758ca983becdbf.1628682049.git.robin.murphy@arm.com Signed-off-by: Joerg Roedel --- Documentation/ABI/testing/sysfs-kernel-iommu_groups | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'Documentation/ABI/testing') diff --git a/Documentation/ABI/testing/sysfs-kernel-iommu_groups b/Documentation/ABI/testing/sysfs-kernel-iommu_groups index eae2f1c1e11e..b15af6a5bc08 100644 --- a/Documentation/ABI/testing/sysfs-kernel-iommu_groups +++ b/Documentation/ABI/testing/sysfs-kernel-iommu_groups @@ -42,8 +42,12 @@ Description: /sys/kernel/iommu_groups//type shows the type of default ======== ====================================================== DMA All the DMA transactions from the device in this group are translated by the iommu. + DMA-FQ As above, but using batched invalidation to lazily + remove translations after use. This may offer reduced + overhead at the cost of reduced memory protection. identity All the DMA transactions from the device in this group - are not translated by the iommu. + are not translated by the iommu. Maximum performance + but zero protection. auto Change to the type the device was booted with. ======== ====================================================== -- cgit v1.2.3