[V6,01/27] memory: qemu_check_ram_volatile

Commit Message

Steven Sistare Aug. 6, 2021, 9:43 p.m. UTC

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

Signed-off-by: Steve Sistare <[e-mail]>
---
 include/exec/memory.h |  8 ++++++++
 softmmu/memory.c      | 26 ++++++++++++++++++++++++++
 2 files changed, 34 insertions(+)

Patch

diff --git a/include/exec/memory.h b/include/exec/memory.h
index c3d417d..0e6d364 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -2925,6 +2925,14 @@  bool ram_block_discard_is_disabled(void);
  */
 bool ram_block_discard_is_required(void);
 
+/**
+ * qemu_ram_check_volatile: return 1 if any memory regions are writable and not
+ * backed by shared memory, else return 0.
+ *
+ * @errp: returned error message identifying the first volatile region found.
+ */
+int qemu_check_ram_volatile(Error **errp);
+
 #endif
 
 #endif
diff --git a/softmmu/memory.c b/softmmu/memory.c
index bfedaf9..e143692 100644
--- a/softmmu/memory.c
+++ b/softmmu/memory.c
@@ -2809,6 +2809,32 @@  void memory_global_dirty_log_stop(void)
     memory_global_dirty_log_do_stop();
 }
 
+static int check_volatile(RAMBlock *rb, void *opaque)
+{
+    MemoryRegion *mr = rb->mr;
+
+    if (mr &&
+        memory_region_is_ram(mr) &&
+        !memory_region_is_ram_device(mr) &&
+        !memory_region_is_rom(mr) &&
+        (rb->fd == -1 || !qemu_ram_is_shared(rb))) {
+        *(const char **)opaque = memory_region_name(mr);
+        return -1;
+    }
+    return 0;
+}
+
+int qemu_check_ram_volatile(Error **errp)
+{
+    char *name;
+
+    if (qemu_ram_foreach_block(check_volatile, &name)) {
+        error_setg(errp, "Memory region %s is volatile", name);
+        return -1;
+    }
+    return 0;
+}
+
 static void listener_add_address_space(MemoryListener *listener,
                                        AddressSpace *as)
 {