[PATCH] xen/efi: boot fix duplicated index, offset calculate operation in the copy_mapping loop

[Paran Lee <p4ranlee@xxxxxxxxx>]

It doesn't seem necessary to do that
duplicated calculation of mfn to addr and l4 table index
in the copy_mapping loop.

Signed-off-by: Paran Lee <p4ranlee@xxxxxxxxx>
---
 xen/common/efi/boot.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/xen/common/efi/boot.c b/xen/common/efi/boot.c
index ac1b235372..7da4269c32 100644
--- a/xen/common/efi/boot.c
+++ b/xen/common/efi/boot.c
@@ -1470,7 +1470,9 @@ static __init void copy_mapping(unsigned long mfn, 
unsigned long end,
 
     for ( ; mfn < end; mfn = next )
     {
-        l4_pgentry_t l4e = efi_l4t[l4_table_offset(mfn << PAGE_SHIFT)];
+        unsigned long addr = mfn << PAGE_SHIFT;
+        unsigned long l4_table_idx = l4_table_offset(addr);
+        l4_pgentry_t l4e = efi_l4t[l4_table_idx];
         unsigned long va = (unsigned long)mfn_to_virt(mfn);
 
         if ( !(mfn & ((1UL << (L4_PAGETABLE_SHIFT - PAGE_SHIFT)) - 1)) )
@@ -1489,7 +1491,7 @@ static __init void copy_mapping(unsigned long mfn, 
unsigned long end,
 
             l3dst = alloc_mapped_pagetable(&l3mfn);
             BUG_ON(!l3dst);
-            efi_l4t[l4_table_offset(mfn << PAGE_SHIFT)] =
+            efi_l4t[l4_table_idx] =
                 l4e_from_mfn(l3mfn, __PAGE_HYPERVISOR);
         }
         else
@@ -1497,7 +1499,7 @@ static __init void copy_mapping(unsigned long mfn, 
unsigned long end,
 
         if ( !l3src )
             l3src = map_l3t_from_l4e(idle_pg_table[l4_table_offset(va)]);
-        l3dst[l3_table_offset(mfn << PAGE_SHIFT)] = l3src[l3_table_offset(va)];
+        l3dst[l3_table_offset(addr)] = l3src[l3_table_offset(va)];
     }
 
     unmap_domain_page(l3src);
-- 
2.25.1