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authorFenghua Yu <fenghua.yu@intel.com>2009-04-25 04:30:20 +0400
committerDavid Woodhouse <David.Woodhouse@intel.com>2009-04-29 09:54:34 +0400
commit4ed0d3e6c64cfd9ba4ceb2099b10d1cf8ece4320 (patch)
tree950bacfaf57040aafbcc2ea9b52eb171d35c23bd /arch/x86/include/asm/iommu.h
parent091069740304c979f957ceacec39c461d0192158 (diff)
downloadlinux-4ed0d3e6c64cfd9ba4ceb2099b10d1cf8ece4320.tar.xz
Intel IOMMU Pass Through Support
The patch adds kernel parameter intel_iommu=pt to set up pass through mode in context mapping entry. This disables DMAR in linux kernel; but KVM still runs on VT-d and interrupt remapping still works. In this mode, kernel uses swiotlb for DMA API functions but other VT-d functionalities are enabled for KVM. KVM always uses multi level translation page table in VT-d. By default, pass though mode is disabled in kernel. This is useful when people don't want to enable VT-d DMAR in kernel but still want to use KVM and interrupt remapping for reasons like DMAR performance concern or debug purpose. Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Acked-by: Weidong Han <weidong@intel.com> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Diffstat (limited to 'arch/x86/include/asm/iommu.h')
-rw-r--r--arch/x86/include/asm/iommu.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86/include/asm/iommu.h b/arch/x86/include/asm/iommu.h
index af326a2975b5..fd6d21bbee6c 100644
--- a/arch/x86/include/asm/iommu.h
+++ b/arch/x86/include/asm/iommu.h
@@ -6,6 +6,7 @@ extern void no_iommu_init(void);
extern struct dma_map_ops nommu_dma_ops;
extern int force_iommu, no_iommu;
extern int iommu_detected;
+extern int iommu_pass_through;
/* 10 seconds */
#define DMAR_OPERATION_TIMEOUT ((cycles_t) tsc_khz*10*1000)