[Xen-devel] [PATCH v4 1/2] swiotlb-xen: implement xen_swiotlb_dma_mmap callback

[Andrii Anisov <andrii.anisov@xxxxxxxxx>]

From: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>

This function creates userspace mapping for the DMA-coherent memory.

Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
Signed-off-by: Oleksandr Dmytryshyn <oleksandr.dmytryshyn@xxxxxxxxxxxxxxx>
Signed-off-by: Andrii Anisov <andrii_anisov@xxxxxxxx>
---
 arch/arm/xen/mm.c         |  1 +
 drivers/xen/swiotlb-xen.c | 19 +++++++++++++++++++
 include/xen/swiotlb-xen.h |  5 +++++
 3 files changed, 25 insertions(+)

diff --git a/arch/arm/xen/mm.c b/arch/arm/xen/mm.c
index bd62d94..cd1684e 100644
--- a/arch/arm/xen/mm.c
+++ b/arch/arm/xen/mm.c
@@ -198,6 +198,7 @@ static struct dma_map_ops xen_swiotlb_dma_ops = {
        .unmap_page = xen_swiotlb_unmap_page,
        .dma_supported = xen_swiotlb_dma_supported,
        .set_dma_mask = xen_swiotlb_set_dma_mask,
+       .mmap = xen_swiotlb_dma_mmap,
 };
 
 int __init xen_mm_init(void)
diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index f8afc6d..728d4e0 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -681,3 +681,22 @@ xen_swiotlb_set_dma_mask(struct device *dev, u64 dma_mask)
        return 0;
 }
 EXPORT_SYMBOL_GPL(xen_swiotlb_set_dma_mask);
+
+/*
+ * Create userspace mapping for the DMA-coherent memory.
+ * This function should be called with the pages from the current domain only,
+ * passing pages mapped from other domains would lead to memory corruption.
+ */
+int
+xen_swiotlb_dma_mmap(struct device *dev, struct vm_area_struct *vma,
+                    void *cpu_addr, dma_addr_t dma_addr, size_t size,
+                    unsigned long attrs)
+{
+#if defined(CONFIG_ARM) || defined(CONFIG_ARM64)
+       if (__generic_dma_ops(dev)->mmap)
+               return __generic_dma_ops(dev)->mmap(dev, vma, cpu_addr,
+                                                   dma_addr, size, attrs);
+#endif
+       return dma_common_mmap(dev, vma, cpu_addr, dma_addr, size);
+}
+EXPORT_SYMBOL_GPL(xen_swiotlb_dma_mmap);
diff --git a/include/xen/swiotlb-xen.h b/include/xen/swiotlb-xen.h
index a0083be..a315c87 100644
--- a/include/xen/swiotlb-xen.h
+++ b/include/xen/swiotlb-xen.h
@@ -55,4 +55,9 @@ xen_swiotlb_dma_supported(struct device *hwdev, u64 mask);
 
 extern int
 xen_swiotlb_set_dma_mask(struct device *dev, u64 dma_mask);
+
+extern int
+xen_swiotlb_dma_mmap(struct device *dev, struct vm_area_struct *vma,
+                    void *cpu_addr, dma_addr_t dma_addr, size_t size,
+                    unsigned long attrs);
 #endif /* __LINUX_SWIOTLB_XEN_H */
-- 
2.7.4


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