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| author | Robin Murphy <robin.murphy@arm.com> | 2021-08-11 13:21:35 +0100 |
|---|---|---|
| committer | Joerg Roedel <jroedel@suse.de> | 2021-08-18 13:27:49 +0200 |
| commit | 26225bea1d84b090b378838a1797daec62d4ad0e (patch) | |
| tree | 5b3a07ac54b9c42482adf6bfca897240ac30037c | |
| parent | c208916fe6c7b84e3ec95cd91853039596eeb2cf (diff) | |
| download | linux-26225bea1d84b090b378838a1797daec62d4ad0e.tar.bz2 | |
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 <baolu.lu@linux.intel.com>
Reviewed-by: John Garry <john.garry@huawei.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/0e08da5ed4069fd3473cfbadda758ca983becdbf.1628682049.git.robin.murphy@arm.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
| -rw-r--r-- | Documentation/ABI/testing/sysfs-kernel-iommu_groups | 6 | ||||
| -rw-r--r-- | drivers/iommu/iommu.c | 2 |
2 files changed, 7 insertions, 1 deletions
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/<grp_id>/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. ======== ====================================================== diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index e09f0d433683..f653a70389ef 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -3268,6 +3268,8 @@ static ssize_t iommu_group_store_type(struct iommu_group *group, req_type = IOMMU_DOMAIN_IDENTITY; else if (sysfs_streq(buf, "DMA")) req_type = IOMMU_DOMAIN_DMA; + else if (sysfs_streq(buf, "DMA-FQ")) + req_type = IOMMU_DOMAIN_DMA_FQ; else if (sysfs_streq(buf, "auto")) req_type = 0; else |