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Date: Fri, 17 May 2024 17:38:03 +0000
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Subject: [PATCH v3 2/2] doc: swiotlb: Document SWIOTLB areas parameter
From: "T.J. Mercier" <tjmercier@google.com>
To: tjmercier@google.com, Thomas Gleixner <tglx@linutronix.de>, 
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>, 
	Dave Hansen <dave.hansen@linux.intel.com>, x86@kernel.org, 
	"H. Peter Anvin" <hpa@zytor.com>, Jonathan Corbet <corbet@lwn.net>, Tianyu Lan <Tianyu.Lan@microsoft.com>
Cc: iommu@lists.linux.dev, isaacmanjarres@google.com, robin.murphy@arm.com, 
	will@kernel.org, joro@8bytes.org, Michael Kelley <mhklinux@outlook.com>, 
	linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org
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Commit 20347fca71a3 ("swiotlb: split up the global swiotlb lock") added
the ability to specify the number of SWIOTLB areas, but boot-options.rst
was not updated as part of that commit. Also adjust the swiotlb option
syntax to clarify that force and noforce are mutually exclusive.

Reported-by: Michael Kelley <mhklinux@outlook.com>
Fixes: 20347fca71a3 ("swiotlb: split up the global swiotlb lock")
Signed-off-by: T.J. Mercier <tjmercier@google.com>
---
 Documentation/arch/x86/x86_64/boot-options.rst | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/Documentation/arch/x86/x86_64/boot-options.rst b/Documentation/arch/x86/x86_64/boot-options.rst
index a37139d1752f..d54e636f91f7 100644
--- a/Documentation/arch/x86/x86_64/boot-options.rst
+++ b/Documentation/arch/x86/x86_64/boot-options.rst
@@ -287,9 +287,11 @@ iommu options only relevant to the AMD GART hardware IOMMU:
 iommu options only relevant to the software bounce buffering (SWIOTLB) IOMMU
 implementation:
 
-    swiotlb=<slots>[,force,noforce]
+    swiotlb=[<slots>][,<areas>][, [force] | [noforce] ]
       <slots>
         Prereserve that many 2K slots for the software IO bounce buffering.
+      <areas>
+        Number of SWIOTLB areas with their own lock. Must be a power of 2.
       force
         Force all IO through the software TLB.
         Hardware IOMMU implementations can use SWIOTLB bounce buffering in
-- 
2.45.0.rc1.225.g2a3ae87e7f-goog