memory: add a readonly attribute to MemoryRegionSection

.readonly cannot be obtained from the MemoryRegion, since it is
inherited from aliases (so you can have a MemoryRegion mapped RW
at one address and RO at another).  Record it in a MemoryRegionSection
for listeners.
Signed-off-by: NAvi Kivity <avi@redhat.com>
Reviewed-by: NRichard Henderson <rth@twiddle.net>

memory.c

@@ -112,6 +112,7 @@ enum ListenerDirection { Forward, Reverse };
         .offset_within_region = (fr)->offset_in_region,                 \
         .size = int128_get64((fr)->addr.size),                          \
         .offset_within_address_space = int128_get64((fr)->addr.start),  \
+        .readonly = (fr)->readonly,                                     \
                 })
 
 struct CoalescedMemoryRange {
@@ -342,6 +343,7 @@ static void as_memory_range_add(AddressSpace *as, FlatRange *fr)
         .offset_within_address_space = int128_get64(fr->addr.start),
         .offset_within_region = fr->offset_in_region,
         .size = int128_get64(fr->addr.size),
+        .readonly = fr->readonly,
     };
 
     cpu_register_physical_memory_log(&section, fr->readable, fr->readonly);
@@ -354,6 +356,7 @@ static void as_memory_range_del(AddressSpace *as, FlatRange *fr)
         .offset_within_address_space = int128_get64(fr->addr.start),
         .offset_within_region = int128_get64(fr->addr.start),
         .size = int128_get64(fr->addr.size),
+        .readonly = fr->readonly,
     };
 
     cpu_register_physical_memory_log(&section, true, false);
@@ -1437,6 +1440,7 @@ MemoryRegionSection memory_region_find(MemoryRegion *address_space,
                                                         fr->addr.start));
     ret.size = int128_get64(range.size);
     ret.offset_within_address_space = int128_get64(range.start);
+    ret.readonly = fr->readonly;
     return ret;
 }
 
@@ -1479,6 +1483,7 @@ static void listener_add_address_space(MemoryListener *listener,
             .offset_within_region = fr->offset_in_region,
             .size = int128_get64(fr->addr.size),
             .offset_within_address_space = int128_get64(fr->addr.start),
+            .readonly = fr->readonly,
         };
         listener->region_add(listener, &section);
     }

memory.h

@@ -160,6 +160,7 @@ typedef struct MemoryRegionSection MemoryRegionSection;
  * @size: the size of the section; will not exceed @mr's boundaries
  * @offset_within_address_space: the address of the first byte of the section
  *     relative to the region's address space
+ * @readonly: writes to this section are ignored
  */
 struct MemoryRegionSection {
     MemoryRegion *mr;
@@ -167,6 +168,7 @@ struct MemoryRegionSection {
     target_phys_addr_t offset_within_region;
     uint64_t size;
     target_phys_addr_t offset_within_address_space;
+    bool readonly;
 };
 
 typedef struct MemoryListener MemoryListener;