36 files changed, 846 insertions, 67 deletions

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 00c1ff45a158..e089e622be79 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1862,6 +1862,12 @@ config CC_STACKPROTECTOR
           neutralized via a kernel panic.
           This feature requires gcc version 4.2 or above.
 
+config SWIOTLB
+        def_bool y
+
+config IOMMU_HELPER
+        def_bool SWIOTLB
+
 config XEN_DOM0
         def_bool y
         depends on XEN
@@ -1872,6 +1878,7 @@ config XEN
         depends on CPU_V7 && !CPU_V6
         depends on !GENERIC_ATOMIC64
         select ARM_PSCI
+        select SWIOTLB_XEN
         help
           Say Y if you want to run Linux in a Virtual Machine on Xen on ARM.
 
diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h
index 863cd84eb1a2..e701a4d9aa59 100644
--- a/arch/arm/include/asm/dma-mapping.h
+++ b/arch/arm/include/asm/dma-mapping.h
@@ -11,17 +11,28 @@
 #include <asm-generic/dma-coherent.h>
 #include <asm/memory.h>
 
+#include <xen/xen.h>
+#include <asm/xen/hypervisor.h>
+
 #define DMA_ERROR_CODE  (~0)
 extern struct dma_map_ops arm_dma_ops;
 extern struct dma_map_ops arm_coherent_dma_ops;
 
-static inline struct dma_map_ops *get_dma_ops(struct device *dev)
+static inline struct dma_map_ops *__generic_dma_ops(struct device *dev)
 {
         if (dev && dev->archdata.dma_ops)
                 return dev->archdata.dma_ops;
         return &arm_dma_ops;
 }
 
+static inline struct dma_map_ops *get_dma_ops(struct device *dev)
+{
+        if (xen_initial_domain())
+                return xen_dma_ops;
+        else
+                return __generic_dma_ops(dev);
+}
+
 static inline void set_dma_ops(struct device *dev, struct dma_map_ops *ops)
 {
         BUG_ON(!dev);
@@ -94,6 +105,39 @@ static inline unsigned long dma_max_pfn(struct device *dev)
 }
 #define dma_max_pfn(dev) dma_max_pfn(dev)
 
+static inline dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
+{
+        unsigned int offset = paddr & ~PAGE_MASK;
+        return pfn_to_dma(dev, __phys_to_pfn(paddr)) + offset;
+}
+
+static inline phys_addr_t dma_to_phys(struct device *dev, dma_addr_t dev_addr)
+{
+        unsigned int offset = dev_addr & ~PAGE_MASK;
+        return __pfn_to_phys(dma_to_pfn(dev, dev_addr)) + offset;
+}
+
+static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t size)
+{
+        u64 limit, mask;
+
+        if (!dev->dma_mask)
+                return 0;
+
+        mask = *dev->dma_mask;
+
+        limit = (mask + 1) & ~mask;
+        if (limit && size > limit)
+                return 0;
+
+        if ((addr | (addr + size - 1)) & ~mask)
+                return 0;
+
+        return 1;
+}
+
+static inline void dma_mark_clean(void *addr, size_t size) { }
+
 /*
  * DMA errors are defined by all-bits-set in the DMA address.
  */
diff --git a/arch/arm/include/asm/io.h b/arch/arm/include/asm/io.h
index d070741b2b37..3c597c222ef2 100644
--- a/arch/arm/include/asm/io.h
+++ b/arch/arm/include/asm/io.h
@@ -24,9 +24,11 @@
 #ifdef __KERNEL__
 
 #include <linux/types.h>
+#include <linux/blk_types.h>
 #include <asm/byteorder.h>
 #include <asm/memory.h>
 #include <asm-generic/pci_iomap.h>
+#include <xen/xen.h>
 
 /*
  * ISA I/O bus memory addresses are 1:1 with the physical address.
@@ -372,6 +374,13 @@ extern void pci_iounmap(struct pci_dev *dev, void __iomem *addr);
 #define BIOVEC_MERGEABLE(vec1, vec2)    \
         ((bvec_to_phys((vec1)) + (vec1)->bv_len) == bvec_to_phys((vec2)))
 
+struct bio_vec;
+extern bool xen_biovec_phys_mergeable(const struct bio_vec *vec1,
+                                      const struct bio_vec *vec2);
+#define BIOVEC_PHYS_MERGEABLE(vec1, vec2)                               \
+        (__BIOVEC_PHYS_MERGEABLE(vec1, vec2) &&                         \
+         (!xen_domain() || xen_biovec_phys_mergeable(vec1, vec2)))
+
 #ifdef CONFIG_MMU
 #define ARCH_HAS_VALID_PHYS_ADDR_RANGE
 extern int valid_phys_addr_range(phys_addr_t addr, size_t size);
diff --git a/arch/arm/include/asm/xen/hypervisor.h b/arch/arm/include/asm/xen/hypervisor.h
index d7ab99a0c9eb..1317ee40f4df 100644
--- a/arch/arm/include/asm/xen/hypervisor.h
+++ b/arch/arm/include/asm/xen/hypervisor.h
@@ -16,4 +16,6 @@ static inline enum