From 5533b2e9bcd222e37ca6c2ff06e79adf9bf036bf Mon Sep 17 00:00:00 2001 From: Liang Li Date: Thu, 5 May 2016 15:32:52 +0800 Subject: [PATCH] migration: Fix a potential issue At the end of live migration and before vm_start() on the destination side, we should make sure all the decompression tasks are finished, if this can not be guaranteed, the VM may get the incorrect memory data, or the updated memory may be overwritten by the decompression thread. Add the code to fix this potential issue. Suggested-by: David Alan Gilbert Suggested-by: Juan Quintela Signed-off-by: Liang Li Message-Id: <1462433579-13691-3-git-send-email-liang.z.li@intel.com> Signed-off-by: Amit Shah --- migration/ram.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/migration/ram.c b/migration/ram.c index f3fe6c7aae..5ccc06840c 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -2223,6 +2223,24 @@ static void *do_data_decompress(void *opaque) return NULL; } +static void wait_for_decompress_done(void) +{ + int idx, thread_count; + + if (!migrate_use_compression()) { + return; + } + + thread_count = migrate_decompress_threads(); + qemu_mutex_lock(&decomp_done_lock); + for (idx = 0; idx < thread_count; idx++) { + while (!decomp_param[idx].done) { + qemu_cond_wait(&decomp_done_cond, &decomp_done_lock); + } + } + qemu_mutex_unlock(&decomp_done_lock); +} + void migrate_decompress_threads_create(void) { int i, thread_count; @@ -2557,6 +2575,7 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id) } } + wait_for_decompress_done(); rcu_read_unlock(); DPRINTF("Completed load of VM with exit code %d seq iteration " "%" PRIu64 "\n", ret, seq_iter);