diff options
author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
---|---|---|
committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
commit | 2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch) | |
tree | 848558de17fb3008cdf4d861b01ac7781903ce39 /arch/arm/xen/mm.c | |
parent | Initial commit. (diff) | |
download | linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip |
Adding upstream version 6.1.76.upstream/6.1.76upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | arch/arm/xen/mm.c | 143 |
1 files changed, 143 insertions, 0 deletions
diff --git a/arch/arm/xen/mm.c b/arch/arm/xen/mm.c new file mode 100644 index 000000000..3d826c0b5 --- /dev/null +++ b/arch/arm/xen/mm.c @@ -0,0 +1,143 @@ +// SPDX-License-Identifier: GPL-2.0-only +#include <linux/cpu.h> +#include <linux/dma-direct.h> +#include <linux/dma-map-ops.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> + +static gfp_t xen_swiotlb_gfp(void) +{ + phys_addr_t base; + u64 i; + + for_each_mem_range(i, &base, NULL) { + if (base < (phys_addr_t)0xffffffff) { + if (IS_ENABLED(CONFIG_ZONE_DMA32)) + return __GFP_DMA32; + return __GFP_DMA; + } + } + + return GFP_KERNEL; +} + +static bool hypercall_cflush = false; + +/* buffers in highmem or foreign pages cannot cross page boundaries */ +static void dma_cache_maint(struct device *dev, dma_addr_t handle, + size_t size, u32 op) +{ + struct gnttab_cache_flush cflush; + + cflush.offset = xen_offset_in_page(handle); + cflush.op = op; + handle &= XEN_PAGE_MASK; + + do { + cflush.a.dev_bus_addr = dma_to_phys(dev, handle); + + 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; + handle += 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, + size_t size, enum dma_data_direction dir) +{ + if (dir != DMA_TO_DEVICE) + dma_cache_maint(dev, handle, size, GNTTAB_CACHE_INVAL); +} + +void xen_dma_sync_for_device(struct device *dev, dma_addr_t handle, + size_t size, enum dma_data_direction dir) +{ + if (dir == DMA_FROM_DEVICE) + dma_cache_maint(dev, handle, size, GNTTAB_CACHE_INVAL); + else + dma_cache_maint(dev, 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(dma_to_phys(dev, 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)); +} + +static int __init xen_mm_init(void) +{ + struct gnttab_cache_flush cflush; + int rc; + + if (!xen_swiotlb_detect()) + return 0; + + /* we can work with the default swiotlb */ + if (!io_tlb_default_mem.nslabs) { + rc = swiotlb_init_late(swiotlb_size_or_default(), + xen_swiotlb_gfp(), NULL); + if (rc < 0) + return rc; + } + + 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); |