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authorLi Zhijian <lizhijian@cn.fujitsu.com>2015-07-02 20:18:06 +0800
committerJuan Quintela <quintela@redhat.com>2015-07-07 14:54:56 +0200
commitdd63169766abd2b8dc33f4451dac5e778458a47c (patch)
tree6a79e5d05025fdd3f6b44ee7ade621ad66c4c878
parent2ff64038a59e8de2baa485806be0838f49f70b79 (diff)
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migration: extend migration_bitmap
Prevously, if we hotplug a device(e.g. device_add e1000) during migration is processing in source side, qemu will add a new ram block but migration_bitmap is not extended. In this case, migration_bitmap will overflow and lead qemu abort unexpectedly. Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com> Signed-off-by: Wen Congyang <wency@cn.fujitsu.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
-rw-r--r--exec.c5
-rw-r--r--include/exec/exec-all.h3
-rw-r--r--migration/ram.c28
3 files changed, 36 insertions, 0 deletions
diff --git a/exec.c b/exec.c
index 251dc79..b7f7f98 100644
--- a/exec.c
+++ b/exec.c
@@ -1414,6 +1414,11 @@ static ram_addr_t ram_block_add(RAMBlock *new_block, Error **errp)
}
}
+ new_ram_size = MAX(old_ram_size,
+ (new_block->offset + new_block->max_length) >> TARGET_PAGE_BITS);
+ if (new_ram_size > old_ram_size) {
+ migration_bitmap_extend(old_ram_size, new_ram_size);
+ }
/* Keep the list sorted from biggest to smallest block. Unlike QTAILQ,
* QLIST (which has an RCU-friendly variant) does not have insertion at
* tail, so save the last element in last_block.
diff --git a/include/exec/exec-all.h b/include/exec/exec-all.h
index d678114..2e74760 100644
--- a/include/exec/exec-all.h
+++ b/include/exec/exec-all.h
@@ -365,4 +365,7 @@ static inline bool cpu_can_do_io(CPUState *cpu)
return cpu->can_do_io != 0;
}
+#if !defined(CONFIG_USER_ONLY)
+void migration_bitmap_extend(ram_addr_t old, ram_addr_t new);
+#endif
#endif
diff --git a/migration/ram.c b/migration/ram.c
index 9c0bcfe..c696814 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -222,6 +222,7 @@ static RAMBlock *last_seen_block;
static RAMBlock *last_sent_block;
static ram_addr_t last_offset;
static unsigned long *migration_bitmap;
+static QemuMutex migration_bitmap_mutex;
static uint64_t migration_dirty_pages;
static uint32_t last_version;
static bool ram_bulk_stage;
@@ -569,11 +570,13 @@ static void migration_bitmap_sync(void)
trace_migration_bitmap_sync_start();
address_space_sync_dirty_bitmap(&address_space_memory);
+ qemu_mutex_lock(&migration_bitmap_mutex);
rcu_read_lock();
QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
migration_bitmap_sync_range(block->mr->ram_addr, block->used_length);
}
rcu_read_unlock();
+ qemu_mutex_unlock(&migration_bitmap_mutex);
trace_migration_bitmap_sync_end(migration_dirty_pages
- num_dirty_pages_init);
@@ -1062,6 +1065,30 @@ static void reset_ram_globals(void)
#define MAX_WAIT 50 /* ms, half buffered_file limit */
+void migration_bitmap_extend(ram_addr_t old, ram_addr_t new)
+{
+ /* called in qemu main thread, so there is
+ * no writing race against this migration_bitmap
+ */
+ if (migration_bitmap) {
+ unsigned long *old_bitmap = migration_bitmap, *bitmap;
+ bitmap = bitmap_new(new);
+
+ /* prevent migration_bitmap content from being set bit
+ * by migration_bitmap_sync_range() at the same time.
+ * it is safe to migration if migration_bitmap is cleared bit
+ * at the same time.
+ */
+ qemu_mutex_lock(&migration_bitmap_mutex);
+ bitmap_copy(bitmap, old_bitmap, old);
+ bitmap_set(bitmap, old, new - old);
+ atomic_rcu_set(&migration_bitmap, bitmap);
+ qemu_mutex_unlock(&migration_bitmap_mutex);
+ migration_dirty_pages += new - old;
+ synchronize_rcu();
+ g_free(old_bitmap);
+ }
+}
/* Each of ram_save_setup, ram_save_iterate and ram_save_complete has
* long-running RCU critical section. When rcu-reclaims in the code
@@ -1078,6 +1105,7 @@ static int ram_save_setup(QEMUFile *f, void *opaque)
dirty_rate_high_cnt = 0;
bitmap_sync_count = 0;
migration_bitmap_sync_init();
+ qemu_mutex_init(&migration_bitmap_mutex);
if (migrate_use_xbzrle()) {
XBZRLE_cache_lock();