Add API to get memory mapping

Add API to get all virtual address and physical address mapping.
If the guest doesn't use paging, the virtual address is equal to the phyical
address. The virtual address and physical address mapping is for gdb's user, and
it does not include the memory that is not referenced by the page table. So if
you want to use crash to anaylze the vmcore, please do not specify -p option.
the reason why the -p option is not default explicitly: guest machine in a
catastrophic state can have corrupted memory, which we cannot trust.

Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>

memory_mapping.c

@@ -164,3 +164,50 @@ void memory_mapping_list_init(MemoryMappingList *list)
     list->last_mapping = NULL;
     QTAILQ_INIT(&list->head);
 }
+
+#if defined(CONFIG_HAVE_GET_MEMORY_MAPPING)
+
+static CPUArchState *find_paging_enabled_cpu(CPUArchState *start_cpu)
+{
+    CPUArchState *env;
+
+    for (env = start_cpu; env != NULL; env = env->next_cpu) {
+        if (cpu_paging_enabled(env)) {
+            return env;
+        }
+    }
+
+    return NULL;
+}
+
+int qemu_get_guest_memory_mapping(MemoryMappingList *list)
+{
+    CPUArchState *env, *first_paging_enabled_cpu;
+    RAMBlock *block;
+    ram_addr_t offset, length;
+    int ret;
+
+    first_paging_enabled_cpu = find_paging_enabled_cpu(first_cpu);
+    if (first_paging_enabled_cpu) {
+        for (env = first_paging_enabled_cpu; env != NULL; env = env->next_cpu) {
+            ret = cpu_get_memory_mapping(list, env);
+            if (ret < 0) {
+                return -1;
+            }
+        }
+        return 0;
+    }
+
+    /*
+     * If the guest doesn't use paging, the virtual address is equal to physical
+     * address.
+     */
+    QLIST_FOREACH(block, &ram_list.blocks, next) {
+        offset = block->offset;
+        length = block->length;
+        create_new_memory_mapping(list, offset, offset, length);
+    }
+
+    return 0;
+}
+#endif

memory_mapping.h

@@ -45,6 +45,21 @@ void memory_mapping_list_free(MemoryMappingList *list);
 
 void memory_mapping_list_init(MemoryMappingList *list);
 
+/*
+ * Return value:
+ *    0: success
+ *   -1: failed
+ *   -2: unsupported
+ */
+#if defined(CONFIG_HAVE_GET_MEMORY_MAPPING)
+int qemu_get_guest_memory_mapping(MemoryMappingList *list);
+#else
+static inline int qemu_get_guest_memory_mapping(MemoryMappingList *list)
+{
+    return -2;
+}
+#endif
+
 #else
 
 /* We use MemoryMappingList* in cpu-all.h */