| // SPDX-License-Identifier: GPL-2.0-only |
| #include <linux/cpu.h> |
| #include <linux/dma-mapping.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/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, unsigned long attrs) |
| { |
| if (is_device_dma_coherent(hwdev)) |
| return; |
| if (attrs & DMA_ATTR_SKIP_CPU_SYNC) |
| 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, |
| unsigned long attrs) |
| |
| { |
| if (is_device_dma_coherent(hwdev)) |
| return; |
| if (attrs & DMA_ATTR_SKIP_CPU_SYNC) |
| 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); |
| |
| const struct dma_map_ops *xen_dma_ops; |
| EXPORT_SYMBOL(xen_dma_ops); |
| |
| 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); |