[PATCH v2 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>
---
 xen/arch/x86/include/asm/page.h |  6 ++++++
 xen/arch/x86/mm.c               | 11 +++--------
 2 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/xen/arch/x86/include/asm/page.h b/xen/arch/x86/include/asm/page.h
index e01af28916b0..6970916d61d5 100644
--- a/xen/arch/x86/include/asm/page.h
+++ b/xen/arch/x86/include/asm/page.h
@@ -200,6 +200,12 @@ static inline l4_pgentry_t l4e_from_paddr(paddr_t pa, 
unsigned int flags)
 #define l4_table_offset(a)         \
     (((a) >> L4_PAGETABLE_SHIFT) & (L4_PAGETABLE_ENTRIES - 1))
 
+/* Check if an address is aligned for a given slot level. */
+#define SLOT_IS_ALIGNED(v, m, s) \
+    IS_ALIGNED(PFN_DOWN(v) | mfn_x(m), (1UL << ((s) - PAGE_SHIFT)) - 1)
+#define IS_L3E_ALIGNED(v, m) SLOT_IS_ALIGNED(v, m, L3_PAGETABLE_SHIFT)
+#define IS_L2E_ALIGNED(v, m) SLOT_IS_ALIGNED(v, m, L2_PAGETABLE_SHIFT)
+
 /* Convert a pointer to a page-table entry into pagetable slot index. */
 #define pgentry_ptr_to_slot(_p)    \
     (((unsigned long)(_p) & ~PAGE_MASK) / sizeof(*(_p)))
diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index d537a799bced..8f7c397a82d4 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -5249,9 +5249,7 @@ 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)) )
         {
@@ -5370,8 +5368,7 @@ 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)) )
         {
@@ -5541,9 +5538,7 @@ 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;
-- 
2.46.0