diff --git a/xen/arch/x86/efi/efi-boot.h b/xen/arch/x86/efi/efi-boot.h
index 23712b2..d355115 100644
--- a/xen/arch/x86/efi/efi-boot.h
+++ b/xen/arch/x86/efi/efi-boot.h
@@ -130,3 +130,74 @@ static void __init place_string(u32 *addr, const char *s)
     }
     *addr = (long)alloc;
 }
+
+static void __init efi_arch_process_memory_map(EFI_SYSTEM_TABLE *SystemTable,
+                                               void *map,
+                                               UINTN map_size,
+                                               UINTN desc_size,
+                                               UINT32 desc_ver)
+{
+    struct e820entry *e;
+    unsigned int i;
+
+    /* Populate E820 table and check trampoline area availability. */
+    e = e820map - 1;
+    for ( i = 0; i < map_size; i += desc_size )
+    {
+        EFI_MEMORY_DESCRIPTOR *desc = map + i;
+        u64 len = desc->NumberOfPages << EFI_PAGE_SHIFT;
+        u32 type;
+
+        switch ( desc->Type )
+        {
+        default:
+            type = E820_RESERVED;
+            break;
+        case EfiConventionalMemory:
+        case EfiBootServicesCode:
+        case EfiBootServicesData:
+            if ( !trampoline_phys && desc->PhysicalStart + len <= 0x100000 &&
+                 len >= cfg.size && desc->PhysicalStart + len > cfg.addr )
+                cfg.addr = (desc->PhysicalStart + len - cfg.size) & PAGE_MASK;
+            /* fall through */
+        case EfiLoaderCode:
+        case EfiLoaderData:
+            if ( desc->Attribute & EFI_MEMORY_WB )
+                type = E820_RAM;
+            else
+        case EfiUnusableMemory:
+                type = E820_UNUSABLE;
+            break;
+        case EfiACPIReclaimMemory:
+            type = E820_ACPI;
+            break;
+        case EfiACPIMemoryNVS:
+            type = E820_NVS;
+            break;
+        }
+        if ( e820nr && type == e->type &&
+             desc->PhysicalStart == e->addr + e->size )
+            e->size += len;
+        else if ( !len || e820nr >= E820MAX )
+            continue;
+        else
+        {
+            ++e;
+            e->addr = desc->PhysicalStart;
+            e->size = len;
+            e->type = type;
+            ++e820nr;
+        }
+    }
+
+}
+
+static void *__init efi_arch_allocate_mmap_buffer(UINTN map_size)
+{
+    place_string(&mbi.mem_upper, NULL);
+    mbi.mem_upper -= map_size;
+    mbi.mem_upper &= -__alignof__(EFI_MEMORY_DESCRIPTOR);
+    if ( mbi.mem_upper < xen_phys_start )
+        return NULL;
+    return (void *)(long)mbi.mem_upper;
+}
diff --git a/xen/common/efi/boot.c b/xen/common/efi/boot.c
index 4d5e310..191a463 100644
--- a/xen/common/efi/boot.c
+++ b/xen/common/efi/boot.c
@@ -664,7 +664,6 @@ efi_start(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE *SystemTable)
     EFI_GRAPHICS_OUTPUT_MODE_INFORMATION *mode_info;
     EFI_FILE_HANDLE dir_handle;
     union string section = { NULL }, name;
-    struct e820entry *e;
     u64 efer;
     bool_t base_video = 0;
 
@@ -966,8 +965,6 @@ efi_start(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE *SystemTable)
     mbi.boot_loader_name = (long)"EFI";
     mbi.mods_addr = (long)mb_modules;
 
-    place_string(&mbi.mem_upper, NULL);
-
     /* Collect EDD info. */
     BUILD_BUG_ON(offsetof(struct edd_info, edd_device_params) != EDDEXTSIZE);
     BUILD_BUG_ON(sizeof(struct edd_device_params) != EDDPARMSIZE);
@@ -1264,65 +1261,18 @@ efi_start(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE *SystemTable)
 
     efi_bs->GetMemoryMap(&efi_memmap_size, NULL, &map_key,
                          &efi_mdesc_size, &mdesc_ver);
-    mbi.mem_upper -= efi_memmap_size;
-    mbi.mem_upper &= -__alignof__(EFI_MEMORY_DESCRIPTOR);
-    if ( mbi.mem_upper < xen_phys_start )
-        blexit(L"Out of static memory");
-    efi_memmap = (void *)(long)mbi.mem_upper;
+    efi_memmap = efi_arch_allocate_mmap_buffer(efi_memmap_size);
+    if ( !efi_memmap )
+        blexit(L"ERROR Unable to allocate memory for EFI memory map");
+
     status = efi_bs->GetMemoryMap(&efi_memmap_size, efi_memmap, &map_key,
                                   &efi_mdesc_size, &mdesc_ver);
     if ( EFI_ERROR(status) )
         PrintErrMesg(L"Cannot obtain memory map", status);
 
-    /* Populate E820 table and check trampoline area availability. */
-    e = e820map - 1;
-    for ( i = 0; i < efi_memmap_size; i += efi_mdesc_size )
-    {
-        EFI_MEMORY_DESCRIPTOR *desc = efi_memmap + i;
-        u64 len = desc->NumberOfPages << EFI_PAGE_SHIFT;
-        u32 type;
+    efi_arch_process_memory_map(SystemTable, efi_memmap, efi_memmap_size,
+                                efi_mdesc_size, mdesc_ver);
 
-        switch ( desc->Type )
-        {
-        default:
-            type = E820_RESERVED;
-            break;
-        case EfiConventionalMemory:
-        case EfiBootServicesCode:
-        case EfiBootServicesData:
-            if ( !trampoline_phys && desc->PhysicalStart + len <= 0x100000 &&
-                 len >= cfg.size && desc->PhysicalStart + len > cfg.addr )
-                cfg.addr = (desc->PhysicalStart + len - cfg.size) & PAGE_MASK;
-            /* fall through */
-        case EfiLoaderCode:
-        case EfiLoaderData:
-            if ( desc->Attribute & EFI_MEMORY_WB )
-                type = E820_RAM;
-            else
-        case EfiUnusableMemory:
-                type = E820_UNUSABLE;
-            break;
-        case EfiACPIReclaimMemory:
-            type = E820_ACPI;
-            break;
-        case EfiACPIMemoryNVS:
-            type = E820_NVS;
-            break;
-        }
-        if ( e820nr && type == e->type &&
-             desc->PhysicalStart == e->addr + e->size )
-            e->size += len;
-        else if ( !len || e820nr >= E820MAX )
-            continue;
-        else
-        {
-            ++e;
-            e->addr = desc->PhysicalStart;
-            e->size = len;
-            e->type = type;
-            ++e820nr;
-        }
-    }
     if ( !trampoline_phys )
     {
         if ( !cfg.addr )
