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4ed0d3e6c6
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>
15 lines
364 B
C
15 lines
364 B
C
#ifndef _ASM_X86_IOMMU_H
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#define _ASM_X86_IOMMU_H
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extern void pci_iommu_shutdown(void);
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extern void no_iommu_init(void);
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extern struct dma_map_ops nommu_dma_ops;
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extern int force_iommu, no_iommu;
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extern int iommu_detected;
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extern int iommu_pass_through;
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/* 10 seconds */
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#define DMAR_OPERATION_TIMEOUT ((cycles_t) tsc_khz*10*1000)
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#endif /* _ASM_X86_IOMMU_H */
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