[18/30] memory: add return value to address_space_rw/read/write

diff --git a/exec.c b/exec.c
index e5ee8ff..4cc5ecb 100644
--- a/exec.c
+++ b/exec.c
@@ -1901,7 +1901,7 @@  static void invalidate_and_set_dirty(hwaddr addr,
     xen_modified_memory(addr, length);
 }
 
-void address_space_rw(AddressSpace *as, hwaddr addr, uint8_t *buf,
+bool address_space_rw(AddressSpace *as, hwaddr addr, uint8_t *buf,
                       int len, bool is_write)
 {
     hwaddr l;
@@ -1909,10 +1909,12 @@  void address_space_rw(AddressSpace *as, hwaddr addr, uint8_t *buf,
     uint32_t val;
     hwaddr addr1;
     MemoryRegionSection *section;
+    bool error = false;
 
     while (len > 0) {
         l = len;
         section = address_space_translate(as, addr, &addr1, &l, is_write);
+        error |= (section == &phys_sections[phys_section_unassigned]);
 
         if (is_write) {
             if (!memory_region_is_ram(section->mr)) {
@@ -1971,31 +1973,26 @@  void address_space_rw(AddressSpace *as, hwaddr addr, uint8_t *buf,
         buf += l;
         addr += l;
     }
+
+    return error;
 }
 
-void address_space_write(AddressSpace *as, hwaddr addr,
+bool address_space_write(AddressSpace *as, hwaddr addr,
                          const uint8_t *buf, int len)
 {
-    address_space_rw(as, addr, (uint8_t *)buf, len, true);
+    return address_space_rw(as, addr, (uint8_t *)buf, len, true);
 }
 
-/**
- * address_space_read: read from an address space.
- *
- * @as: #AddressSpace to be accessed
- * @addr: address within that address space
- * @buf: buffer with the data transferred
- */
-void address_space_read(AddressSpace *as, hwaddr addr, uint8_t *buf, int len)
+bool address_space_read(AddressSpace *as, hwaddr addr, uint8_t *buf, int len)
 {
-    address_space_rw(as, addr, buf, len, false);
+    return address_space_rw(as, addr, buf, len, false);
 }
 
 
 void cpu_physical_memory_rw(hwaddr addr, uint8_t *buf,
                             int len, int is_write)
 {
-    return address_space_rw(&address_space_memory, addr, buf, len, is_write);
+    address_space_rw(&address_space_memory, addr, buf, len, is_write);
 }
 
 /* used for ROM loading : can write in RAM and ROM */
diff --git a/include/exec/memory.h b/include/exec/memory.h
index 809a958..94709d1 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -816,32 +816,38 @@  void address_space_destroy(AddressSpace *as);
 /**
  * address_space_rw: read from or write to an address space.
  *
+ * Return true if the operation hit any unassigned memory.
+ *
  * @as: #AddressSpace to be accessed
  * @addr: address within that address space
  * @buf: buffer with the data transferred
  * @is_write: indicates the transfer direction
  */
-void address_space_rw(AddressSpace *as, hwaddr addr, uint8_t *buf,
+bool address_space_rw(AddressSpace *as, hwaddr addr, uint8_t *buf,
                       int len, bool is_write);
 
 /**
  * address_space_write: write to address space.
  *
+ * Return true if the operation hit any unassigned memory.
+ *
  * @as: #AddressSpace to be accessed
  * @addr: address within that address space
  * @buf: buffer with the data transferred
  */
-void address_space_write(AddressSpace *as, hwaddr addr,
+bool address_space_write(AddressSpace *as, hwaddr addr,
                          const uint8_t *buf, int len);
 
 /**
  * address_space_read: read from an address space.
  *
+ * Return true if the operation hit any unassigned memory.
+ *
  * @as: #AddressSpace to be accessed
  * @addr: address within that address space
  * @buf: buffer with the data transferred
  */
-void address_space_read(AddressSpace *as, hwaddr addr, uint8_t *buf, int len);
+bool address_space_read(AddressSpace *as, hwaddr addr, uint8_t *buf, int len);
 
 /* address_space_translate: translate an address range into an address space
  * into a MemoryRegionSection and an address range into that section