[V4,01/25] qemu_ram_volatile

Commit Message

Steven Sistare July 6, 2021, 4:45 p.m. UTC

Add a function that returns true if any ram_list block represents
volatile memory.

Signed-off-by: Steve Sistare <[e-mail]>
---
 include/exec/memory.h |  8 ++++++++
 softmmu/memory.c      | 30 ++++++++++++++++++++++++++++++
 2 files changed, 38 insertions(+)

Patch

diff --git a/include/exec/memory.h b/include/exec/memory.h
index 5728a68..e8b71d8 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -2629,6 +2629,14 @@  bool ram_block_discard_is_disabled(void);
  */
 bool ram_block_discard_is_required(void);
 
+/**
+ * qemu_ram_volatile: return true if any memory regions are writable and not
+ * backed by shared memory.
+ *
+ * @errp: returned error message identifying the bad region.
+ */
+bool qemu_ram_volatile(Error **errp);
+
 #endif
 
 #endif
diff --git a/softmmu/memory.c b/softmmu/memory.c
index d4493ef..7197559 100644
--- a/softmmu/memory.c
+++ b/softmmu/memory.c
@@ -2707,6 +2707,36 @@  void memory_global_dirty_log_stop(void)
     memory_global_dirty_log_do_stop();
 }
 
+/*
+ * Return true if any memory regions are writable and not backed by shared
+ * memory.
+ */
+bool qemu_ram_volatile(Error **errp)
+{
+    RAMBlock *block;
+    MemoryRegion *mr;
+    bool ret = false;
+
+    rcu_read_lock();
+    QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
+        mr = block->mr;
+        if (mr &&
+            memory_region_is_ram(mr) &&
+            !memory_region_is_ram_device(mr) &&
+            !memory_region_is_rom(mr) &&
+            (block->fd == -1 || !qemu_ram_is_shared(block))) {
+
+            error_setg(errp, "Memory region %s is volatile",
+                       memory_region_name(mr));
+            ret = true;
+            break;
+        }
+    }
+
+    rcu_read_unlock();
+    return ret;
+}
+
 static void listener_add_address_space(MemoryListener *listener,
                                        AddressSpace *as)
 {