exec: introduce qemu_ram_unset_idstr() to unset RAMBlock idstr

Signed-off-by: NHu Tao <hutao@cn.fujitsu.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

exec.c

@@ -1201,17 +1201,24 @@ static void qemu_ram_setup_dump(void *addr, ram_addr_t size)
     }
 }
 
-void qemu_ram_set_idstr(ram_addr_t addr, const char *name, DeviceState *dev)
+static RAMBlock *find_ram_block(ram_addr_t addr)
 {
-    RAMBlock *new_block, *block;
+    RAMBlock *block;
 
-    new_block = NULL;
     QTAILQ_FOREACH(block, &ram_list.blocks, next) {
         if (block->offset == addr) {
-            new_block = block;
-            break;
+            return block;
         }
     }
+
+    return NULL;
+}
+
+void qemu_ram_set_idstr(ram_addr_t addr, const char *name, DeviceState *dev)
+{
+    RAMBlock *new_block = find_ram_block(addr);
+    RAMBlock *block;
+
     assert(new_block);
     assert(!new_block->idstr[0]);
 
@@ -1236,6 +1243,15 @@ void qemu_ram_set_idstr(ram_addr_t addr, const char *name, DeviceState *dev)
     qemu_mutex_unlock_ramlist();
 }
 
+void qemu_ram_unset_idstr(ram_addr_t addr)
+{
+    RAMBlock *block = find_ram_block(addr);
+
+    if (block) {
+        memset(block->idstr, 0, sizeof(block->idstr));
+    }
+}
+
 static int memory_try_enable_merging(void *addr, size_t len)
 {
     if (!qemu_opt_get_bool(qemu_get_machine_opts(), "mem-merge", true)) {

include/exec/cpu-common.h

@@ -54,6 +54,7 @@ void qemu_ram_remap(ram_addr_t addr, ram_addr_t length);
 /* This should not be used by devices.  */
 MemoryRegion *qemu_ram_addr_from_host(void *ptr, ram_addr_t *ram_addr);
 void qemu_ram_set_idstr(ram_addr_t addr, const char *name, DeviceState *dev);
+void qemu_ram_unset_idstr(ram_addr_t addr);
 
 void cpu_physical_memory_rw(hwaddr addr, uint8_t *buf,
                             int len, int is_write);