[PATCH v3 1/4] x86/mm: introduce helpers to detect super page alignment

[Roger Pau Monne <roger.pau@xxxxxxxxxx>]

Split the code that detects whether the physical and linear address of a
mapping request are suitable to be used in an L3 or L2 slot.

No functional change intended.

Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
---
Changes since v2:
 - Fix parenthesization of macro parameter.
 - Add another usage of IS_L2E_ALIGNED().

Changes since v1:
 - Make the macros local to map_pages_to_xen().
 - Some adjustments to macro logic.
---
 xen/arch/x86/mm.c | 25 ++++++++++++++-----------
 1 file changed, 14 insertions(+), 11 deletions(-)

diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index 11933321a3d5..ebb50a7836ac 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -5493,6 +5493,13 @@ int map_pages_to_xen(
     }                                          \
 } while (0)
 
+/* Check if a (virt, mfn) tuple is aligned for a given slot level. */
+#define IS_LnE_ALIGNED(v, m, n)                                 \
+    IS_ALIGNED(PFN_DOWN(v) | mfn_x(m),                          \
+               (1UL << (PAGETABLE_ORDER * ((n) - 1))) - 1)
+#define IS_L2E_ALIGNED(v, m) IS_LnE_ALIGNED(v, m, 2)
+#define IS_L3E_ALIGNED(v, m) IS_LnE_ALIGNED(v, m, 3)
+
     L3T_INIT(current_l3page);
 
     while ( nr_mfns != 0 )
@@ -5510,9 +5517,7 @@ int map_pages_to_xen(
         L3T_LOCK(current_l3page);
         ol3e = *pl3e;
 
-        if ( cpu_has_page1gb &&
-             !(((virt >> PAGE_SHIFT) | mfn_x(mfn)) &
-               ((1UL << (L3_PAGETABLE_SHIFT - PAGE_SHIFT)) - 1)) &&
+        if ( cpu_has_page1gb && IS_L3E_ALIGNED(virt, mfn) &&
              nr_mfns >= (1UL << (L3_PAGETABLE_SHIFT - PAGE_SHIFT)) &&
              !(flags & (_PAGE_PAT | MAP_SMALL_PAGES)) )
         {
@@ -5631,8 +5636,7 @@ int map_pages_to_xen(
         if ( !pl2e )
             goto out;
 
-        if ( ((((virt >> PAGE_SHIFT) | mfn_x(mfn)) &
-               ((1u << PAGETABLE_ORDER) - 1)) == 0) &&
+        if ( IS_L2E_ALIGNED(virt, mfn) &&
              (nr_mfns >= (1u << PAGETABLE_ORDER)) &&
              !(flags & (_PAGE_PAT|MAP_SMALL_PAGES)) )
         {
@@ -5749,9 +5753,7 @@ int map_pages_to_xen(
             nr_mfns -= 1UL;
 
             if ( (flags == PAGE_HYPERVISOR) &&
-                 ((nr_mfns == 0) ||
-                  ((((virt >> PAGE_SHIFT) | mfn_x(mfn)) &
-                    ((1u << PAGETABLE_ORDER) - 1)) == 0)) )
+                 ((nr_mfns == 0) || IS_L2E_ALIGNED(virt, mfn)) )
             {
                 unsigned long base_mfn;
                 const l1_pgentry_t *l1t;
@@ -5802,9 +5804,7 @@ int map_pages_to_xen(
  check_l3:
         if ( cpu_has_page1gb &&
              (flags == PAGE_HYPERVISOR) &&
-             ((nr_mfns == 0) ||
-              !(((virt >> PAGE_SHIFT) | mfn_x(mfn)) &
-                ((1UL << (L3_PAGETABLE_SHIFT - PAGE_SHIFT)) - 1))) )
+             ((nr_mfns == 0) || IS_L3E_ALIGNED(virt, mfn)) )
         {
             unsigned long base_mfn;
             const l2_pgentry_t *l2t;
@@ -5848,6 +5848,9 @@ int map_pages_to_xen(
         }
     }
 
+#undef IS_L3E_ALIGNED
+#undef IS_L2E_ALIGNED
+#undef IS_LnE_ALIGNED
 #undef flush_flags
 
     rc = 0;
-- 
2.46.0