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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /arch/arm/xen/mm.c
parentInitial commit. (diff)
downloadlinux-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.c143
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);