[Qemu-devel] [PATCH v3 04/35] add a version number to ram_list

[Isaku Yamahata]

From: Umesh Deshpande <address@hidden>

From: Umesh Deshpande <address@hidden>

This will be used to detect if last_block might have become invalid
across different calls to ram_save_live.

Signed-off-by: Paolo Bonzini <address@hidden>
Signed-off-by: Umesh Deshpande <address@hidden>
---
 arch_init.c |    7 ++++++-
 cpu-all.h   |    1 +
 exec.c      |    5 ++++-
 3 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/arch_init.c b/arch_init.c
index d6162af..eb36a6a 100644
--- a/arch_init.c
+++ b/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
  *
@@ -558,6 +558,7 @@ static void reset_ram_globals(void)
 {
     last_block = NULL;
     last_offset = 0;
+    last_version = ram_list.version;
     sort_ram_list();
 }
 
@@ -613,6 +614,10 @@ 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);
 
diff --git a/cpu-all.h b/cpu-all.h
index ecbba12..84aea8b 100644
--- a/cpu-all.h
+++ b/cpu-all.h
@@ -500,6 +500,7 @@ typedef struct RAMBlock {
 
 typedef struct RAMList {
     uint8_t *phys_dirty;
+    uint32_t version;
     QLIST_HEAD(, RAMBlock) blocks_mru;
     QLIST_HEAD(, RAMBlock) blocks;
 } RAMList;
diff --git a/exec.c b/exec.c
index 489d924..f5a8aca 100644
--- a/exec.c
+++ b/exec.c
@@ -645,7 +645,6 @@ bool tcg_enabled(void)
 void cpu_exec_init_all(void)
 {
 #if !defined(CONFIG_USER_ONLY)
-    qemu_mutex_init(&ram_list.mutex);
     memory_map_init();
     io_mem_init();
 #endif
@@ -2570,6 +2569,8 @@ ram_addr_t qemu_ram_alloc_from_ptr(ram_addr_t size, void 
*host,
     QLIST_INSERT_HEAD(&ram_list.blocks, new_block, next);
     QLIST_INSERT_HEAD(&ram_list.blocks_mru, new_block, next_mru);
 
+    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),
@@ -2598,6 +2599,7 @@ void qemu_ram_free_from_ptr(ram_addr_t addr)
         if (addr == block->offset) {
             QLIST_REMOVE(block, next);
             QLIST_REMOVE(block, next_mru);
+            ram_list.version++;
             g_free(block);
             return;
         }
@@ -2612,6 +2614,7 @@ void qemu_ram_free(ram_addr_t addr)
         if (addr == block->offset) {
             QLIST_REMOVE(block, next);
             QLIST_REMOVE(block, next_mru);
+            ram_list.version++;
             if (block->flags & RAM_PREALLOC_MASK) {
                 ;
             } else if (mem_path) {
-- 
1.7.10.4