#include <linux/cpu.h> #include <linux/dma-mapping.h> #include <linux/bootmem.h> #include <linux/gfp.h> #include <linux/highmem.h> #include <linux/export.h> #include <linux/memblock.h> #include <linux/of_address.h> #include <linux/slab.h> #include <linux/types.h> #include <linux/dma-mapping.h> #include <linux/vmalloc.h> #include <linux/swiotlb.h> #include <xen/xen.h> #include <xen/interface/grant_table.h> #include <xen/interface/memory.h> #include <xen/page.h> #include <xen/swiotlb-xen.h> #include <asm/cacheflush.h> #include <asm/xen/hypercall.h> #include <asm/xen/interface.h> unsigned long xen_get_swiotlb_free_pages(unsigned int order) { struct memblock_region *reg; gfp_t flags = __GFP_NOWARN|__GFP_KSWAPD_RECLAIM; for_each_memblock(memory, reg) { if (reg->base < (phys_addr_t)0xffffffff) { flags |= __GFP_DMA; break; } } return __get_free_pages(flags, order); } enum dma_cache_op { DMA_UNMAP, DMA_MAP, }; static bool hypercall_cflush = false; /* functions called by SWIOTLB */ static void dma_cache_maint(dma_addr_t handle, unsigned long offset, size_t size, enum dma_data_direction dir, enum dma_cache_op op) { struct gnttab_cache_flush cflush; unsigned long xen_pfn; size_t left = size; xen_pfn = (handle >> XEN_PAGE_SHIFT) + offset / XEN_PAGE_SIZE; offset %= XEN_PAGE_SIZE; do { size_t len = left; /* buffers in highmem or foreign pages cannot cross page * boundaries */ if (len + offset > XEN_PAGE_SIZE) len = XEN_PAGE_SIZE - offset; cflush.op = 0; cflush.a.dev_bus_addr = xen_pfn << XEN_PAGE_SHIFT; cflush.offset = offset; cflush.length = len; if (op == DMA_UNMAP && dir != DMA_TO_DEVICE) cflush.op = GNTTAB_CACHE_INVAL; if (op == DMA_MAP) { if (dir == DMA_FROM_DEVICE) cflush.op = GNTTAB_CACHE_INVAL; else cflush.op = GNTTAB_CACHE_CLEAN; } if (cflush.op) HYPERVISOR_grant_table_op(GNTTABOP_cache_flush, &cflush, 1); offset = 0; xen_pfn++; left -= len; } while (left); } static void __xen_dma_page_dev_to_cpu(struct device *hwdev, dma_addr_t handle, size_t size, enum dma_data_direction dir) { dma_cache_maint(handle & PAGE_MASK, handle & ~PAGE_MASK, size, dir, DMA_UNMAP); } static void __xen_dma_page_cpu_to_dev(struct device *hwdev, dma_addr_t handle, size_t size, enum dma_data_direction dir) { dma_cache_maint(handle & PAGE_MASK, handle & ~PAGE_MASK, size, dir, DMA_MAP); } void __xen_dma_map_page(struct device *hwdev, struct page *page, dma_addr_t dev_addr, unsigned long offset, size_t size, enum dma_data_direction dir, struct dma_attrs *attrs) { if (is_device_dma_coherent(hwdev)) return; if (dma_get_attr(DMA_ATTR_SKIP_CPU_SYNC, attrs)) return; __xen_dma_page_cpu_to_dev(hwdev, dev_addr, size, dir); } void __xen_dma_unmap_page(struct device *hwdev, dma_addr_t handle, size_t size, enum dma_data_direction dir, struct dma_attrs *attrs) { if (is_device_dma_coherent(hwdev)) return; if (dma_get_attr(DMA_ATTR_SKIP_CPU_SYNC, attrs)) return; __xen_dma_page_dev_to_cpu(hwdev, handle, size, dir); } void __xen_dma_sync_single_for_cpu(struct device *hwdev, dma_addr_t handle, size_t size, enum dma_data_direction dir) { if (is_device_dma_coherent(hwdev)) return; __xen_dma_page_dev_to_cpu(hwdev, handle, size, dir); } void __xen_dma_sync_single_for_device(struct device *hwdev, dma_addr_t handle, size_t size, enum dma_data_direction dir) { if (is_device_dma_coherent(hwdev)) return; __xen_dma_page_cpu_to_dev(hwdev, handle, size, dir); } bool xen_arch_need_swiotlb(struct device *dev, phys_addr_t phys, dma_addr_t dev_addr) { unsigned int xen_pfn = XEN_PFN_DOWN(phys); unsigned int bfn = XEN_PFN_DOWN(dev_addr); /* * The swiotlb buffer should be used if * - Xen doesn't have the cache flush hypercall * - The Linux page refers to foreign memory * - The device doesn't support coherent DMA request * * The Linux page may be spanned acrros multiple Xen page, although * it's not possible to have a mix of local and foreign Xen page. * Furthermore, range_straddles_page_boundary is already checking * if buffer is physically contiguous in the host RAM. * * Therefore we only need to check the first Xen page to know if we * require a bounce buffer because the device doesn't support coherent * memory and we are not able to flush the cache. */ return (!hypercall_cflush && (xen_pfn != bfn) && !is_device_dma_coherent(dev)); } int xen_create_contiguous_region(phys_addr_t pstart, unsigned int order, unsigned int address_bits, dma_addr_t *dma_handle) { if (!xen_initial_domain()) return -EINVAL; /* we assume that dom0 is mapped 1:1 for now */ *dma_handle = pstart; return 0; } EXPORT_SYMBOL_GPL(xen_create_contiguous_region); void xen_destroy_contiguous_region(phys_addr_t pstart, unsigned int order) { return; } EXPORT_SYMBOL_GPL(xen_destroy_contiguous_region); struct dma_map_ops *xen_dma_ops; EXPORT_SYMBOL(xen_dma_ops); static struct dma_map_ops xen_swiotlb_dma_ops = { .mapping_error = xen_swiotlb_dma_mapping_error, .alloc = xen_swiotlb_alloc_coherent, .free = xen_swiotlb_free_coherent, .sync_single_for_cpu = xen_swiotlb_sync_single_for_cpu, .sync_single_for_device = xen_swiotlb_sync_single_for_device, .sync_sg_for_cpu = xen_swiotlb_sync_sg_for_cpu, .sync_sg_for_device = xen_swiotlb_sync_sg_for_device, .map_sg = xen_swiotlb_map_sg_attrs, .unmap_sg = xen_swiotlb_unmap_sg_attrs, .map_page = xen_swiotlb_map_page, .unmap_page = xen_swiotlb_unmap_page, .dma_supported = xen_swiotlb_dma_supported, .set_dma_mask = xen_swiotlb_set_dma_mask, }; int __init xen_mm_init(void) { struct gnttab_cache_flush cflush; if (!xen_initial_domain()) return 0; xen_swiotlb_init(1, false); xen_dma_ops = &xen_swiotlb_dma_ops; cflush.op = 0; cflush.a.dev_bus_addr = 0; cflush.offset = 0; cflush.length = 0; if (HYPERVISOR_grant_table_op(GNTTABOP_cache_flush, &cflush, 1) != -ENOSYS) hypercall_cflush = true; return 0; } arch_initcall(xen_mm_init);