Merge tag 'iommu-updates-v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git...

[platform/kernel/linux-rpi.git] / Documentation / admin-guide / kernel-parameters.txt

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 1c0a3cf..02470ba 100644 (file)
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1877,13 +1877,6 @@
                        bypassed by not enabling DMAR with this option. In
                        this case, gfx device will use physical address for
                        DMA.
-               forcedac [X86-64]
-                       With this option iommu will not optimize to look
-                       for io virtual address below 32-bit forcing dual
-                       address cycle on pci bus for cards supporting greater
-                       than 32-bit addressing. The default is to look
-                       for translation below 32-bit and if not available
-                       then look in the higher range.
                strict [Default Off]
                        With this option on every unmap_single operation will
                        result in a hardware IOTLB flush operation as opposed
@@ -1972,6 +1965,14 @@
                nobypass        [PPC/POWERNV]
                        Disable IOMMU bypass, using IOMMU for PCI devices.
 
+       iommu.forcedac= [ARM64, X86] Control IOVA allocation for PCI devices.
+                       Format: { "0" | "1" }
+                       0 - Try to allocate a 32-bit DMA address first, before
+                         falling back to the full range if needed.
+                       1 - Allocate directly from the full usable range,
+                         forcing Dual Address Cycle for PCI cards supporting
+                         greater than 32-bit addressing.
+
        iommu.strict=   [ARM64] Configure TLB invalidation behaviour
                        Format: { "0" | "1" }
                        0 - Lazy mode.