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authorIngo Molnar <mingo@elte.hu>2009-09-04 14:44:16 +0200
committerIngo Molnar <mingo@elte.hu>2009-09-04 14:44:16 +0200
commit695a461296e5df148c99ac087b9e1cb380f4db15 (patch)
tree951893036fdc0b7bae0e17bc739ac8ffe909781d /arch/x86/kernel/pci-dma.c
parentc7084b35eb1a4d3353a501508baf9d3d82822c93 (diff)
parent2b681fafcc50fea6304ed418667c9d04282acb73 (diff)
Merge branch 'amd-iommu/2.6.32' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/linux-2.6-iommu into core/iommu
Diffstat (limited to 'arch/x86/kernel/pci-dma.c')
-rw-r--r--arch/x86/kernel/pci-dma.c9
1 files changed, 8 insertions, 1 deletions
diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
index 3c945c0b350..8fb4ce35bea 100644
--- a/arch/x86/kernel/pci-dma.c
+++ b/arch/x86/kernel/pci-dma.c
@@ -32,7 +32,14 @@ int no_iommu __read_mostly;
/* Set this to 1 if there is a HW IOMMU in the system */
int iommu_detected __read_mostly = 0;
-int iommu_pass_through;
+/*
+ * This variable becomes 1 if iommu=pt is passed on the kernel command line.
+ * If this variable is 1, IOMMU implementations do no DMA ranslation for
+ * devices and allow every device to access to whole physical memory. This is
+ * useful if a user want to use an IOMMU only for KVM device assignment to
+ * guests and not for driver dma translation.
+ */
+int iommu_pass_through __read_mostly;
dma_addr_t bad_dma_address __read_mostly = 0;
EXPORT_SYMBOL(bad_dma_address);