[Qemu-devel] [PATCH 09/34] add a version number to ram_list

[Juan Quintela <quintela@redhat.com>]

From: Umesh Deshpande <udeshpan@redhat.com>

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 <pbonzini@redhat.com>
Signed-off-by: Umesh Deshpande <udeshpan@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

Reviewed-by: Orit Wasserman <owasserm@redhat.com>
---
 arch_init.c | 7 ++++++-
 cpu-all.h   | 1 +
 exec.c      | 4 ++++
 3 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/arch_init.c b/arch_init.c
index 8b5980f..136d0e8 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
  *
@@ -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);

diff --git a/cpu-all.h b/cpu-all.h
index cd61320..c69d602 100644
--- a/cpu-all.h
+++ b/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;

diff --git a/exec.c b/exec.c
index 5f501d4..4474d60 100644
--- a/exec.c
+++ b/exec.c
@@ -1055,6 +1055,8 @@ 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),
@@ -1083,6 +1085,7 @@ 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;
         }
@@ -1097,6 +1100,7 @@ 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) {
-- 
1.7.11.7