[v4][PATCH 6/9] xen:x86:: support xc_reserved_device_memory_map in compat case

[Tiejun Chen <tiejun.chen@intel.com>]

We also need to make sure xc_reserved_device_memory_map can
work in compat case.

Mostly refer to that complete xc_reserved_device_memory_map
hypercall definition, just work with struct
compat_reserved_device_memory_map and struct
compat_reserved_device_memory.

Signed-off-by: Tiejun Chen <tiejun.chen@intel.com>
---
 xen/arch/x86/x86_64/compat/mm.c | 62 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 62 insertions(+)

diff --git a/xen/arch/x86/x86_64/compat/mm.c b/xen/arch/x86/x86_64/compat/mm.c
index 69c6195..887a778 100644
--- a/xen/arch/x86/x86_64/compat/mm.c
+++ b/xen/arch/x86/x86_64/compat/mm.c
@@ -215,6 +215,68 @@ int compat_arch_memory_op(unsigned long cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
         break;
     }
 
+    case XENMEM_reserved_device_memory_map:
+    {
+        struct compat_reserved_device_memory_map map;
+        unsigned int i = 0;
+        static unsigned int nr_entries = 0;
+        static struct compat_reserved_device_memory *rmrr_map;
+        struct acpi_rmrr_unit *rmrr;
+
+        if ( copy_from_guest(&map, arg, 1) )
+            return -EFAULT;
+
+        if ( !nr_entries )
+            /* Currently we just need to cover RMRR. */
+            list_for_each_entry( rmrr, &acpi_rmrr_units, list )
+                nr_entries++;
+
+        if ( !nr_entries )
+            return -ENOENT;
+        else
+        {
+            if ( rmrr_map == NULL )
+            {
+                rmrr_map = xmalloc_array(compat_reserved_device_memory_t,
+                                         nr_entries);
+                if ( rmrr_map == NULL )
+                {
+                    return -ENOMEM;
+                }
+
+                list_for_each_entry( rmrr, &acpi_rmrr_units, list )
+                {
+                    rmrr_map[i].pfn = rmrr->base_address >> PAGE_SHIFT;
+                    rmrr_map[i].count = PAGE_ALIGN(rmrr->end_address -
+                                                   rmrr->base_address) /
+                                                   PAGE_SIZE;
+                    i++;
+                }
+            }
+        }
+
+        if ( map.nr_entries < nr_entries )
+        {
+            map.nr_entries =  nr_entries;
+            if ( copy_to_guest(arg, &map, 1) )
+                return -EFAULT;
+            return -ENOBUFS;
+        }
+
+        map.nr_entries = nr_entries;
+
+        for ( i = 0; i < map.nr_entries; ++i )
+        {
+            if ( copy_to_compat_offset(map.buffer, i, rmrr_map + i, 1) )
+                return -EFAULT;
+        }
+
+        if ( copy_to_guest(arg, &map, 1) )
+            return -EFAULT;
+
+        break;
+    }
+
     default:
         rc = -ENOSYS;
         break;
-- 
1.9.1