[PATCH v2 1/5] x86: convert set_gpfn_from_mfn() to a function

[Jan Beulich <jbeulich@xxxxxxxx>]

It is already a little too heavy for a macro, and more logic is about to
get added to it.

This also allows reducing the scope of compat_machine_to_phys_mapping.

Requested-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
---
v2: New.

--- a/xen/arch/x86/x86_64/mm.c
+++ b/xen/arch/x86/x86_64/mm.c
@@ -40,6 +40,8 @@ EMIT_FILE;
 #include <asm/mem_sharing.h>
 #include <public/memory.h>
 
+#define compat_machine_to_phys_mapping ((unsigned int 
*)RDWR_COMPAT_MPT_VIRT_START)
+
 unsigned int __read_mostly m2p_compat_vstart = __HYPERVISOR_COMPAT_VIRT_START;
 
 l2_pgentry_t *compat_idle_pg_table_l2;
@@ -1454,6 +1456,20 @@ destroy_frametable:
     return ret;
 }
 
+void set_gpfn_from_mfn(unsigned long mfn, unsigned long pfn)
+{
+    const struct domain *d = page_get_owner(mfn_to_page(_mfn(mfn)));
+    unsigned long entry = (d && (d == dom_cow)) ? SHARED_M2P_ENTRY : pfn;
+
+    if ( unlikely(!machine_to_phys_mapping_valid) )
+        return;
+
+    if ( mfn < (RDWR_COMPAT_MPT_VIRT_END - RDWR_COMPAT_MPT_VIRT_START) / 4 )
+        compat_machine_to_phys_mapping[mfn] = entry;
+
+    machine_to_phys_mapping[mfn] = entry;
+}
+
 #include "compat/mm.c"
 
 /*
--- a/xen/include/asm-x86/mm.h
+++ b/xen/include/asm-x86/mm.h
@@ -494,25 +494,13 @@ extern paddr_t mem_hotplug;
 #define SHARED_M2P_ENTRY         (~0UL - 1UL)
 #define SHARED_M2P(_e)           ((_e) == SHARED_M2P_ENTRY)
 
-#define compat_machine_to_phys_mapping ((unsigned int 
*)RDWR_COMPAT_MPT_VIRT_START)
-#define _set_gpfn_from_mfn(mfn, pfn) ({                        \
-    struct domain *d = page_get_owner(mfn_to_page(_mfn(mfn))); \
-    unsigned long entry = (d && (d == dom_cow)) ?              \
-        SHARED_M2P_ENTRY : (pfn);                              \
-    ((void)((mfn) >= (RDWR_COMPAT_MPT_VIRT_END - RDWR_COMPAT_MPT_VIRT_START) / 
4 || \
-            (compat_machine_to_phys_mapping[(mfn)] = (unsigned int)(entry))), \
-     machine_to_phys_mapping[(mfn)] = (entry));                \
-    })
-
 /*
  * Disable some users of set_gpfn_from_mfn() (e.g., free_heap_pages()) until
  * the machine_to_phys_mapping is actually set up.
  */
 extern bool machine_to_phys_mapping_valid;
-#define set_gpfn_from_mfn(mfn, pfn) do {        \
-    if ( machine_to_phys_mapping_valid )        \
-        _set_gpfn_from_mfn(mfn, pfn);           \
-} while (0)
+
+void set_gpfn_from_mfn(unsigned long mfn, unsigned long pfn);
 
 extern struct rangeset *mmio_ro_ranges;