[PATCH] Document iommu=panic

Signed-off-by: Andi Kleen <ak@suse.de>

2 files changed, 2 insertions, 0 deletions

diff --git a/Documentation/x86_64/boot-options.txt b/Documentation/x86_64/boot-options.txt
index e97a4c8fe6ea..74b77f9e91bc 100644
--- a/Documentation/x86_64/boot-options.txt
+++ b/Documentation/x86_64/boot-options.txt
@@ -203,6 +203,7 @@ IOMMU
             When off all DMA over >4GB is forced through an IOMMU or bounce
             buffering.
    nodac    Forbid DMA >4GB
+   panic    Always panic when IOMMU overflows
 
   swiotlb=pages[,force]
 
diff --git a/arch/x86_64/kernel/pci-dma.c b/arch/x86_64/kernel/pci-dma.c
index 58be7929b4e2..f8d857453f8a 100644
--- a/arch/x86_64/kernel/pci-dma.c
+++ b/arch/x86_64/kernel/pci-dma.c
@@ -245,6 +245,7 @@ EXPORT_SYMBOL(dma_set_mask);
    noaperture Don't touch the aperture for AGP.
    allowdac Allow DMA >4GB
    nodac    Forbid DMA >4GB
+   panic    Force panic when IOMMU overflows
 */
 __init int iommu_setup(char *p)
 {