[PATCH v2 6/9] x86/shadow: re-work 4-level SHADOW_FOREACH_L2E()

[Jan Beulich <jbeulich@xxxxxxxx>]

First of all move the almost loop-invariant condition out of the loop;
transform it into an altered loop boundary. Since the new local variable
wants to be "unsigned int" and named without violating name space rules,
convert the loop induction variable accordingly.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
---
v2: New.

--- a/xen/arch/x86/mm/shadow/multi.c
+++ b/xen/arch/x86/mm/shadow/multi.c
@@ -863,23 +863,20 @@ do {
 /* 64-bit l2: touch all entries except for PAE compat guests. */
 #define SHADOW_FOREACH_L2E(_sl2mfn, _sl2e, _gl2p, _done, _dom, _code)       \
 do {                                                                        \
-    int _i;                                                                 \
-    int _xen = !shadow_mode_external(_dom);                                 \
+    unsigned int i_, end_ = SHADOW_L2_PAGETABLE_ENTRIES;                    \
     shadow_l2e_t *_sp = map_domain_page((_sl2mfn));                         \
     ASSERT_VALID_L2(mfn_to_page(_sl2mfn)->u.sh.type);                       \
-    for ( _i = 0; _i < SHADOW_L2_PAGETABLE_ENTRIES; _i++ )                  \
+    if ( !shadow_mode_external(_dom) &&                                     \
+         is_pv_32bit_domain(_dom) &&                                        \
+         mfn_to_page(_sl2mfn)->u.sh.type != SH_type_l2_64_shadow )          \
+        end_ = COMPAT_L2_PAGETABLE_FIRST_XEN_SLOT(_dom);                    \
+    for ( i_ = 0; i_ < end_; ++i_ )                                         \
     {                                                                       \
-        if ( (!(_xen))                                                      \
-             || !is_pv_32bit_domain(_dom)                                   \
-             || mfn_to_page(_sl2mfn)->u.sh.type == SH_type_l2_64_shadow     \
-             || (_i < COMPAT_L2_PAGETABLE_FIRST_XEN_SLOT(_dom)) )           \
-        {                                                                   \
-            (_sl2e) = _sp + _i;                                             \
-            if ( shadow_l2e_get_flags(*(_sl2e)) & _PAGE_PRESENT )           \
-                {_code}                                                     \
-            if ( _done ) break;                                             \
-            increment_ptr_to_guest_entry(_gl2p);                            \
-        }                                                                   \
+        (_sl2e) = _sp + i_;                                                 \
+        if ( shadow_l2e_get_flags(*(_sl2e)) & _PAGE_PRESENT )               \
+            { _code }                                                       \
+        if ( _done ) break;                                                 \
+        increment_ptr_to_guest_entry(_gl2p);                                \
     }                                                                       \
     unmap_domain_page(_sp);                                                 \
 } while (0)