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authorZhen Lei <thunder.leizhen@huawei.com>2021-07-12 19:12:17 +0800
committerJoerg Roedel <jroedel@suse.de>2021-07-26 13:27:38 +0200
commit712d8f205835c1d170e85d7811da3d9f36d8fab7 (patch)
tree1a3c0c3868e40bae3b9dd2bb62a1197f2f1c6cf0 /Documentation
parentd8577d2e331dc06f5871afa6b76035dd8b74c903 (diff)
downloadlinux-712d8f205835c1d170e85d7811da3d9f36d8fab7.tar.bz2
iommu: Enhance IOMMU default DMA mode build options
First, add build options IOMMU_DEFAULT_{LAZY|STRICT}, so that we have the opportunity to set {lazy|strict} mode as default at build time. Then put the two config options in an choice, as they are mutually exclusive. [jpg: Make choice between strict and lazy only (and not passthrough)] Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> Signed-off-by: John Garry <john.garry@huawei.com> Reviewed-by: Robin Murphy <robin.murphy@arm.com> Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com> Link: https://lore.kernel.org/r/1626088340-5838-4-git-send-email-john.garry@huawei.com Signed-off-by: Joerg Roedel <jroedel@suse.de>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/admin-guide/kernel-parameters.txt3
1 files changed, 2 insertions, 1 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index a04d2748c99a..90b525cf0ec2 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -2042,9 +2042,10 @@
throughput at the cost of reduced device isolation.
Will fall back to strict mode if not supported by
the relevant IOMMU driver.
- 1 - Strict mode (default).
+ 1 - Strict mode.
DMA unmap operations invalidate IOMMU hardware TLBs
synchronously.
+ unset - Use value of CONFIG_IOMMU_DEFAULT_{LAZY,STRICT}.
Note: on x86, the default behaviour depends on the
equivalent driver-specific parameters, but a strict
mode explicitly specified by either method takes