Loading...
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 | // SPDX-License-Identifier: GPL-2.0-only #include <linux/cpu.h> #include <linux/dma-noncoherent.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) { if (IS_ENABLED(CONFIG_ZONE_DMA32)) flags |= __GFP_DMA32; else flags |= __GFP_DMA; break; } } return __get_free_pages(flags, order); } static bool hypercall_cflush = false; /* buffers in highmem or foreign pages cannot cross page boundaries */ static void dma_cache_maint(dma_addr_t handle, size_t size, u32 op) { struct gnttab_cache_flush cflush; cflush.a.dev_bus_addr = handle & XEN_PAGE_MASK; cflush.offset = xen_offset_in_page(handle); cflush.op = op; do { if (size + cflush.offset > XEN_PAGE_SIZE) cflush.length = XEN_PAGE_SIZE - cflush.offset; else cflush.length = size; HYPERVISOR_grant_table_op(GNTTABOP_cache_flush, &cflush, 1); cflush.offset = 0; cflush.a.dev_bus_addr += cflush.length; size -= cflush.length; } while (size); } /* * Dom0 is mapped 1:1, and while the Linux page can span across multiple Xen * pages, it is not possible for it to contain a mix of local and foreign Xen * pages. Calling pfn_valid on a foreign mfn will always return false, so if * pfn_valid returns true the pages is local and we can use the native * dma-direct functions, otherwise we call the Xen specific version. */ void xen_dma_sync_for_cpu(struct device *dev, dma_addr_t handle, phys_addr_t paddr, size_t size, enum dma_data_direction dir) { if (pfn_valid(PFN_DOWN(handle))) arch_sync_dma_for_cpu(dev, paddr, size, dir); else if (dir != DMA_TO_DEVICE) dma_cache_maint(handle, size, GNTTAB_CACHE_INVAL); } void xen_dma_sync_for_device(struct device *dev, dma_addr_t handle, phys_addr_t paddr, size_t size, enum dma_data_direction dir) { if (pfn_valid(PFN_DOWN(handle))) arch_sync_dma_for_device(dev, paddr, size, dir); else if (dir == DMA_FROM_DEVICE) dma_cache_maint(handle, size, GNTTAB_CACHE_INVAL); else dma_cache_maint(handle, size, GNTTAB_CACHE_CLEAN); } 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) && !dev_is_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; } void xen_destroy_contiguous_region(phys_addr_t pstart, unsigned int order) { return; } int __init xen_mm_init(void) { struct gnttab_cache_flush cflush; if (!xen_initial_domain()) return 0; xen_swiotlb_init(1, false); 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); |