add a version number to ram_list

This will be used to detect if last_block might have become invalid
across different calls to ram_save_live.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NUmesh Deshpande <udeshpan@redhat.com>
Signed-off-by: NJuan Quintela <quintela@redhat.com>
Reviewed-by: NOrit Wasserman <owasserm@redhat.com>

arch_init.c

@@ -336,6 +336,7 @@ static RAMBlock *last_block;
 static ram_addr_t last_offset;
 static unsigned long *migration_bitmap;
 static uint64_t migration_dirty_pages;
+static uint32_t last_version;
 
 static inline bool migration_bitmap_test_and_reset_dirty(MemoryRegion *mr,
                                                          ram_addr_t offset)
@@ -406,7 +407,6 @@ static void migration_bitmap_sync(void)
     }
 }
 
-
 /*
  * ram_save_block: Writes a page of memory to the stream f
  *
@@ -533,6 +533,7 @@ static void reset_ram_globals(void)
 {
     last_block = NULL;
     last_offset = 0;
+    last_version = ram_list.version;
 }
 
 #define MAX_WAIT 50 /* ms, half buffered_file limit */
@@ -587,6 +588,10 @@ static int ram_save_iterate(QEMUFile *f, void *opaque)
     uint64_t expected_downtime;
     MigrationState *s = migrate_get_current();
 
+    if (ram_list.version != last_version) {
+        reset_ram_globals();
+    }
+
     bytes_transferred_last = bytes_transferred;
     bwidth = qemu_get_clock_ns(rt_clock);
 

exec.c

@@ -1056,6 +1056,8 @@ ram_addr_t qemu_ram_alloc_from_ptr(ram_addr_t size, void *host,
     }
     ram_list.mru_block = NULL;
 
+    ram_list.version++;
+
     ram_list.phys_dirty = g_realloc(ram_list.phys_dirty,
                                        last_ram_offset() >> TARGET_PAGE_BITS);
     memset(ram_list.phys_dirty + (new_block->offset >> TARGET_PAGE_BITS),
@@ -1084,6 +1086,7 @@ void qemu_ram_free_from_ptr(ram_addr_t addr)
         if (addr == block->offset) {
             QTAILQ_REMOVE(&ram_list.blocks, block, next);
             ram_list.mru_block = NULL;
+            ram_list.version++;
             g_free(block);
             return;
         }
@@ -1098,6 +1101,7 @@ void qemu_ram_free(ram_addr_t addr)
         if (addr == block->offset) {
             QTAILQ_REMOVE(&ram_list.blocks, block, next);
             ram_list.mru_block = NULL;
+            ram_list.version++;
             if (block->flags & RAM_PREALLOC_MASK) {
                 ;
             } else if (mem_path) {

include/exec/cpu-all.h

@@ -497,6 +497,7 @@ typedef struct RAMList {
     uint8_t *phys_dirty;
     RAMBlock *mru_block;
     QTAILQ_HEAD(, RAMBlock) blocks;
+    uint32_t version;
 } RAMList;
 extern RAMList ram_list;