From: Kurt Garloff <garloff@xxxxxxx>
Subject: Use io_remap_page_range in DRM

When remapping non-RAM-backed pages, remap_pfn_range will crash
then domain under Xen. This happens when using the DRM drivers. 

Signed-off-by: Kurt Garloff <garloff@xxxxxxx>

Index: linux-2.6.11/drivers/char/drm/drm_vm.c
===================================================================
--- linux-2.6.11.orig/drivers/char/drm/drm_vm.c
+++ linux-2.6.11/drivers/char/drm/drm_vm.c
@@ -628,8 +628,14 @@ int drm_mmap(struct file *filp, struct v
 		if (io_remap_page_range(DRM_RPR_ARG(vma) vma->vm_start,
 					VM_OFFSET(vma) + offset,
 					vma->vm_end - vma->vm_start,
 					vma->vm_page_prot, 0))
+#elif defined(CONFIG_XEN)
+		if (io_remap_page_range(vma, vma->vm_start,
+					VM_OFFSET(vma) + offset,
+					vma->vm_end - vma->vm_start,
+					vma->vm_page_prot))
+			
 #else
 		if (remap_pfn_range(DRM_RPR_ARG(vma) vma->vm_start,
 				     (VM_OFFSET(vma) + offset) >> PAGE_SHIFT,
 				     vma->vm_end - vma->vm_start,