[Xen-devel] [PATCH MM-PART3 v2 01/12] xen/arm: lpae: Add a macro to generate offsets from an address

[Julien Grall <julien.grall@xxxxxxx>]

There are few places requiring to generate offsets from an address.
Rather than open-coding everywhere, we can introduce a macro to do the
job for us.

Signed-off-by: Julien Grall <julien.grall@xxxxxxx>
Reviewed-by: Andrii Anisov <andrii_anisov@xxxxxxxx>

---
    Changes in v2:
        - Add Andrii's reviewed-by
---
 xen/arch/arm/p2m.c         | 23 +++--------------------
 xen/include/asm-arm/lpae.h |  9 +++++++++
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
index 92c2413f20..06fa342a8f 100644
--- a/xen/arch/arm/p2m.c
+++ b/xen/arch/arm/p2m.c
@@ -368,12 +368,7 @@ mfn_t p2m_get_entry(struct p2m_domain *p2m, gfn_t gfn,
     p2m_type_t _t;
 
     /* Convenience aliases */
-    const unsigned int offsets[4] = {
-        zeroeth_table_offset(addr),
-        first_table_offset(addr),
-        second_table_offset(addr),
-        third_table_offset(addr)
-    };
+    DECLARE_OFFSETS(offsets, addr);
 
     ASSERT(p2m_is_locked(p2m));
     BUILD_BUG_ON(THIRD_MASK != PAGE_MASK);
@@ -888,7 +883,6 @@ static int __p2m_set_entry(struct p2m_domain *p2m,
                            p2m_type_t t,
                            p2m_access_t a)
 {
-    paddr_t addr = gfn_to_gaddr(sgfn);
     unsigned int level = 0;
     unsigned int target = 3 - (page_order / LPAE_SHIFT);
     lpae_t *entry, *table, orig_pte;
@@ -897,12 +891,7 @@ static int __p2m_set_entry(struct p2m_domain *p2m,
     bool removing_mapping = mfn_eq(smfn, INVALID_MFN);
 
     /* Convenience aliases */
-    const unsigned int offsets[4] = {
-        zeroeth_table_offset(addr),
-        first_table_offset(addr),
-        second_table_offset(addr),
-        third_table_offset(addr)
-    };
+    DECLARE_OFFSETS(offsets, gfn_to_gaddr(sgfn));
 
     ASSERT(p2m_is_write_locked(p2m));
 
@@ -1199,15 +1188,9 @@ bool p2m_resolve_translation_fault(struct domain *d, 
gfn_t gfn)
     unsigned int level = 0;
     bool resolved = false;
     lpae_t entry, *table;
-    paddr_t addr = gfn_to_gaddr(gfn);
 
     /* Convenience aliases */
-    const unsigned int offsets[4] = {
-        zeroeth_table_offset(addr),
-        first_table_offset(addr),
-        second_table_offset(addr),
-        third_table_offset(addr)
-    };
+    DECLARE_OFFSETS(offsets, gfn_to_gaddr(gfn));
 
     p2m_write_lock(p2m);
 
diff --git a/xen/include/asm-arm/lpae.h b/xen/include/asm-arm/lpae.h
index 545b0c8f24..c22780f8f3 100644
--- a/xen/include/asm-arm/lpae.h
+++ b/xen/include/asm-arm/lpae.h
@@ -218,6 +218,15 @@ TABLE_OFFSET_HELPERS(64);
 #undef TABLE_OFFSET
 #undef TABLE_OFFSET_HELPERS
 
+/* Generate an array @var containing the offset for each level from @addr */
+#define DECLARE_OFFSETS(var, addr)          \
+    const unsigned int var[4] = {           \
+        zeroeth_table_offset(addr),         \
+        first_table_offset(addr),           \
+        second_table_offset(addr),          \
+        third_table_offset(addr)            \
+    }
+
 #endif /* __ASSEMBLY__ */
 
 /*
-- 
2.11.0


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