From: Robin Murphy <robin.murphy@arm.com>
To: joro@8bytes.org
Cc: will@kernel.org, john.garry@huawei.com,
iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org,
baolu.lu@linux.intel.com
Subject: [PATCH] iommu: Update "iommu.strict" documentation
Date: Mon, 14 Jun 2021 15:57:26 +0100 [thread overview]
Message-ID: <2c8c06e1b449d6b060c5bf9ad3b403cd142f405d.1623682646.git.robin.murphy@arm.com> (raw)
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: a250c23f15c2 ("iommu: remove DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE")
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
---
Documentation/admin-guide/kernel-parameters.txt | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index cb89dbdedc46..20a32de990ed 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -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.
--
2.25.1
next reply other threads:[~2021-06-14 14:57 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-14 14:57 Robin Murphy [this message]
2021-06-14 16:29 ` [PATCH] iommu: Update "iommu.strict" documentation John Garry
2021-06-15 7:05 ` Lu Baolu
2021-06-17 15:04 ` Joerg Roedel
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