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>
60 lines
1.6 KiB
C
60 lines
1.6 KiB
C
/* Glue code to lib/swiotlb.c */
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#include <linux/pci.h>
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#include <linux/cache.h>
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#include <linux/module.h>
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#include <linux/dma-mapping.h>
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#include <asm/swiotlb.h>
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#include <asm/dma.h>
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#include <asm/iommu.h>
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#include <asm/machvec.h>
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int swiotlb __read_mostly;
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EXPORT_SYMBOL(swiotlb);
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static void *ia64_swiotlb_alloc_coherent(struct device *dev, size_t size,
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dma_addr_t *dma_handle, gfp_t gfp)
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{
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if (dev->coherent_dma_mask != DMA_BIT_MASK(64))
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gfp |= GFP_DMA;
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return swiotlb_alloc_coherent(dev, size, dma_handle, gfp);
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}
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struct dma_map_ops swiotlb_dma_ops = {
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.alloc_coherent = ia64_swiotlb_alloc_coherent,
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.free_coherent = swiotlb_free_coherent,
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.map_page = swiotlb_map_page,
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.unmap_page = swiotlb_unmap_page,
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.map_sg = swiotlb_map_sg_attrs,
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.unmap_sg = swiotlb_unmap_sg_attrs,
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.sync_single_for_cpu = swiotlb_sync_single_for_cpu,
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.sync_single_for_device = swiotlb_sync_single_for_device,
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.sync_single_range_for_cpu = swiotlb_sync_single_range_for_cpu,
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.sync_single_range_for_device = swiotlb_sync_single_range_for_device,
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.sync_sg_for_cpu = swiotlb_sync_sg_for_cpu,
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.sync_sg_for_device = swiotlb_sync_sg_for_device,
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.dma_supported = swiotlb_dma_supported,
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.mapping_error = swiotlb_dma_mapping_error,
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};
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void __init swiotlb_dma_init(void)
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{
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dma_ops = &swiotlb_dma_ops;
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swiotlb_init();
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}
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void __init pci_swiotlb_init(void)
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{
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if (!iommu_detected || iommu_pass_through) {
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#ifdef CONFIG_IA64_GENERIC
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swiotlb = 1;
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printk(KERN_INFO "PCI-DMA: Re-initialize machine vector.\n");
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machvec_init("dig");
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swiotlb_init();
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dma_ops = &swiotlb_dma_ops;
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#else
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panic("Unable to find Intel IOMMU");
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#endif
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}
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}
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