memory: Switch memory from using AddressSpace to FlatView

FlatView's will be shared between AddressSpace's and subpage_t
and MemoryRegionSection cannot store AS anymore, hence this change.

In particular, for:

 typedef struct subpage_t {
     MemoryRegion iomem;
-    AddressSpace *as;
+    FlatView *fv;
     hwaddr base;
     uint16_t sub_section[];
 } subpage_t;

  struct MemoryRegionSection {
     MemoryRegion *mr;
-    AddressSpace *address_space;
+    FlatView *fv;
     hwaddr offset_within_region;
     Int128 size;
     hwaddr offset_within_address_space;
     bool readonly;
 };

This should cause no behavioural change.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Message-Id: <20170921085110.25598-7-aik@ozlabs.ru>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

memory.c

diff --git a/memory.c b/memory.c
index 962e9b9..bf3728a 100644
--- a/memory.c
+++ b/memory.c
@@ -154,7 +154,8 @@
 /* No need to ref/unref .mr, the FlatRange keeps it alive.  */
 #define MEMORY_LISTENER_UPDATE_REGION(fr, as, dir, callback, _args...)  \
     do {                                                                \
-        MemoryRegionSection mrs = section_from_flat_range(fr, as);      \
+        MemoryRegionSection mrs = section_from_flat_range(fr,           \
+                address_space_to_flatview(as));                         \
         MEMORY_LISTENER_CALL(as, callback, dir, &mrs, ##_args);         \
     } while(0)
 
@@ -208,7 +209,6 @@
 }
 
 typedef struct FlatRange FlatRange;
-typedef struct FlatView FlatView;
 
 /* Range of memory in the global map.  Addresses are absolute. */
 struct FlatRange {
@@ -238,11 +238,11 @@
     for (var = (view)->ranges; var < (view)->ranges + (view)->nr; ++var)
 
 static inline MemoryRegionSection
-section_from_flat_range(FlatRange *fr, AddressSpace *as)
+section_from_flat_range(FlatRange *fr, FlatView *fv)
 {
     return (MemoryRegionSection) {
         .mr = fr->mr,
-        .address_space = as,
+        .fv = fv,
         .offset_within_region = fr->offset_in_region,
         .size = fr->addr.size,
         .offset_within_address_space = int128_get64(fr->addr.start),
@@ -312,7 +312,7 @@
     }
 }
 
-static FlatView *address_space_to_flatview(AddressSpace *as)
+FlatView *address_space_to_flatview(AddressSpace *as)
 {
     return atomic_rcu_read(&as->current_map);
 }
@@ -761,7 +761,7 @@
                                                   fds_new[inew]))) {
             fd = &fds_old[iold];
             section = (MemoryRegionSection) {
-                .address_space = as,
+                .fv = address_space_to_flatview(as),
                 .offset_within_address_space = int128_get64(fd->addr.start),
                 .size = fd->addr.size,
             };
@@ -774,7 +774,7 @@
                                                          fds_old[iold]))) {
             fd = &fds_new[inew];
             section = (MemoryRegionSection) {
-                .address_space = as,
+                .fv = address_space_to_flatview(as),
                 .offset_within_address_space = int128_get64(fd->addr.start),
                 .size = fd->addr.size,
             };
@@ -794,7 +794,7 @@
 
     rcu_read_lock();
     do {
-        view = atomic_rcu_read(&as->current_map);
+        view = address_space_to_flatview(as);
         /* If somebody has replaced as->current_map concurrently,
          * flatview_ref returns false.
          */
@@ -913,8 +913,8 @@
     new_view->dispatch = mem_begin(as);
     for (i = 0; i < new_view->nr; i++) {
         MemoryRegionSection mrs =
-            section_from_flat_range(&new_view->ranges[i], as);
-        mem_add(as, new_view, &mrs);
+            section_from_flat_range(&new_view->ranges[i], new_view);
+        mem_add(new_view, &mrs);
     }
     mem_commit(new_view->dispatch);
 
@@ -1870,7 +1870,7 @@
         view = address_space_get_flatview(as);
         FOR_EACH_FLAT_RANGE(fr, view) {
             if (fr->mr == mr) {
-                MemoryRegionSection mrs = section_from_flat_range(fr, as);
+                MemoryRegionSection mrs = section_from_flat_range(fr, view);
                 listener->log_sync(listener, &mrs);
             }
         }
@@ -1973,7 +1973,7 @@
     FOR_EACH_FLAT_RANGE(fr, view) {
         if (fr->mr == mr) {
             section = (MemoryRegionSection) {
-                .address_space = as,
+                .fv = view,
                 .offset_within_address_space = int128_get64(fr->addr.start),
                 .size = fr->addr.size,
             };
@@ -2324,7 +2324,7 @@
     }
     range = addrrange_make(int128_make64(addr), int128_make64(size));
 
-    view = atomic_rcu_read(&as->current_map);
+    view = address_space_to_flatview(as);
     fr = flatview_lookup(view, range);
     if (!fr) {
         return ret;
@@ -2335,7 +2335,7 @@
     }
 
     ret.mr = fr->mr;
-    ret.address_space = as;
+    ret.fv = view;
     range = addrrange_intersection(range, fr->addr);
     ret.offset_within_region = fr->offset_in_region;
     ret.offset_within_region += int128_get64(int128_sub(range.start,
@@ -2384,7 +2384,8 @@
         view = address_space_get_flatview(as);
         FOR_EACH_FLAT_RANGE(fr, view) {
             if (fr->dirty_log_mask) {
-                MemoryRegionSection mrs = section_from_flat_range(fr, as);
+                MemoryRegionSection mrs = section_from_flat_range(fr, view);
+
                 listener->log_sync(listener, &mrs);
             }
         }
@@ -2469,7 +2470,7 @@
     FOR_EACH_FLAT_RANGE(fr, view) {
         MemoryRegionSection section = {
             .mr = fr->mr,
-            .address_space = as,
+            .fv = view,
             .offset_within_region = fr->offset_in_region,
             .size = fr->addr.size,
             .offset_within_address_space = int128_get64(fr->addr.start),