[PATCH 3/9] xen: add hooks for mapping phys<->bus addresses in swiotlb

[Jeremy Fitzhardinge]

From: Ian Campbell <ian.campbell@xxxxxxxxxx>

Impact: Xen support for DMA

Add hooks to allow Xen to do translation between pfn and mfns for the swiotlb
layer, so that dma actually ends up going to the proper machine pages.

Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@xxxxxxxxxx>
Reviewed-by: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: FUJITA Tomonori <fujita.tomonori@xxxxxxxxxxxxx>
---
 arch/x86/kernel/pci-swiotlb.c |   10 ----------
 arch/x86/xen/pci-swiotlb.c    |   18 ++++++++++++++++++
 drivers/pci/xen-iommu.c       |   11 +++++++++++
 include/xen/swiotlb.h         |    2 ++
 4 files changed, 31 insertions(+), 10 deletions(-)

diff --git a/arch/x86/kernel/pci-swiotlb.c b/arch/x86/kernel/pci-swiotlb.c
index bc09da7..3216674 100644
--- a/arch/x86/kernel/pci-swiotlb.c
+++ b/arch/x86/kernel/pci-swiotlb.c
@@ -13,16 +13,6 @@
 
 int swiotlb __read_mostly;
 
-dma_addr_t swiotlb_phys_to_bus(struct device *hwdev, phys_addr_t paddr)
-{
-	return paddr;
-}
-
-phys_addr_t swiotlb_bus_to_phys(dma_addr_t baddr)
-{
-	return baddr;
-}
-
 int __weak swiotlb_arch_range_needs_mapping(phys_addr_t paddr, size_t size)
 {
 	return 0;
diff --git a/arch/x86/xen/pci-swiotlb.c b/arch/x86/xen/pci-swiotlb.c
index 25f0365..1d43fde 100644
--- a/arch/x86/xen/pci-swiotlb.c
+++ b/arch/x86/xen/pci-swiotlb.c
@@ -1,5 +1,7 @@
 #include <linux/bootmem.h>
 #include <linux/gfp.h>
+#include <linux/dma-mapping.h>
+#include <linux/swiotlb.h>
 
 #include <xen/swiotlb.h>
 #include <asm/xen/hypervisor.h>
@@ -25,3 +27,19 @@ void *swiotlb_alloc(unsigned order, unsigned long nslabs)
 	WARN_ON(1);
 	return NULL;
 }
+
+dma_addr_t swiotlb_phys_to_bus(struct device *hwdev, phys_addr_t paddr)
+{
+	if (xen_pv_domain())
+		return xen_phys_to_bus(paddr);
+
+	return paddr;
+}
+
+phys_addr_t swiotlb_bus_to_phys(dma_addr_t baddr)
+{
+	if (xen_pv_domain())
+		return xen_bus_to_phys(baddr);
+
+	return baddr;
+}
diff --git a/drivers/pci/xen-iommu.c b/drivers/pci/xen-iommu.c
index b9b4620..e3d6ddb 100644
--- a/drivers/pci/xen-iommu.c
+++ b/drivers/pci/xen-iommu.c
@@ -59,6 +59,17 @@ void xen_swiotlb_fixup(void *buf, size_t size, unsigned long nslabs)
 			panic(KERN_ERR "xen_create_contiguous_region failed\n");
 	}
 }
+
+dma_addr_t xen_phys_to_bus(phys_addr_t paddr)
+{
+	return phys_to_machine(XPADDR(paddr)).maddr;
+}
+
+phys_addr_t xen_bus_to_phys(dma_addr_t daddr)
+{
+	return machine_to_phys(XMADDR(daddr)).paddr;
+}
+
 static inline int address_needs_mapping(struct device *hwdev,
 						dma_addr_t addr)
 {
diff --git a/include/xen/swiotlb.h b/include/xen/swiotlb.h
index 67b7b42..4229f27 100644
--- a/include/xen/swiotlb.h
+++ b/include/xen/swiotlb.h
@@ -2,5 +2,7 @@
 #define _XEN_SWIOTLB_H
 
 extern void xen_swiotlb_fixup(void *buf, size_t size, unsigned long nslabs);
+extern phys_addr_t xen_bus_to_phys(dma_addr_t daddr);
+extern dma_addr_t xen_phys_to_bus(phys_addr_t paddr);
 
 #endif /* _XEN_SWIOTLB_H */
-- 
1.6.0.6

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