| // 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/xen-ops.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(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(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; |
| } |
| |
| static 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); |