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b097186fd2
This patchset: PV guests under Xen are running in an non-contiguous memory architecture. When PCI pass-through is utilized, this necessitates an IOMMU for translating bus (DMA) to virtual and vice-versa and also providing a mechanism to have contiguous pages for device drivers operations (say DMA operations). Specifically, under Xen the Linux idea of pages is an illusion. It assumes that pages start at zero and go up to the available memory. To help with that, the Linux Xen MMU provides a lookup mechanism to translate the page frame numbers (PFN) to machine frame numbers (MFN) and vice-versa. The MFN are the "real" frame numbers. Furthermore memory is not contiguous. Xen hypervisor stitches memory for guests from different pools, which means there is no guarantee that PFN==MFN and PFN+1==MFN+1. Lastly with Xen 4.0, pages (in debug mode) are allocated in descending order (high to low), meaning the guest might never get any MFN's under the 4GB mark. Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Acked-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Cc: Albert Herranz <albert_herranz@yahoo.es> Cc: Ian Campbell <Ian.Campbell@citrix.com>
66 lines
2.0 KiB
C
66 lines
2.0 KiB
C
#ifndef __LINUX_SWIOTLB_XEN_H
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#define __LINUX_SWIOTLB_XEN_H
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#include <linux/swiotlb.h>
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extern void xen_swiotlb_init(int verbose);
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extern void
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*xen_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
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dma_addr_t *dma_handle, gfp_t flags);
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extern void
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xen_swiotlb_free_coherent(struct device *hwdev, size_t size,
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void *vaddr, dma_addr_t dma_handle);
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extern dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
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unsigned long offset, size_t size,
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enum dma_data_direction dir,
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struct dma_attrs *attrs);
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extern void xen_swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr,
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size_t size, enum dma_data_direction dir,
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struct dma_attrs *attrs);
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/*
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extern int
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xen_swiotlb_map_sg(struct device *hwdev, struct scatterlist *sg, int nents,
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enum dma_data_direction dir);
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extern void
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xen_swiotlb_unmap_sg(struct device *hwdev, struct scatterlist *sg, int nents,
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enum dma_data_direction dir);
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*/
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extern int
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xen_swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
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int nelems, enum dma_data_direction dir,
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struct dma_attrs *attrs);
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extern void
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xen_swiotlb_unmap_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
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int nelems, enum dma_data_direction dir,
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struct dma_attrs *attrs);
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extern void
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xen_swiotlb_sync_single_for_cpu(struct device *hwdev, dma_addr_t dev_addr,
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size_t size, enum dma_data_direction dir);
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extern void
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xen_swiotlb_sync_sg_for_cpu(struct device *hwdev, struct scatterlist *sg,
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int nelems, enum dma_data_direction dir);
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extern void
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xen_swiotlb_sync_single_for_device(struct device *hwdev, dma_addr_t dev_addr,
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size_t size, enum dma_data_direction dir);
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extern void
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xen_swiotlb_sync_sg_for_device(struct device *hwdev, struct scatterlist *sg,
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int nelems, enum dma_data_direction dir);
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extern int
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xen_swiotlb_dma_mapping_error(struct device *hwdev, dma_addr_t dma_addr);
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extern int
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xen_swiotlb_dma_supported(struct device *hwdev, u64 mask);
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#endif /* __LINUX_SWIOTLB_XEN_H */
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