[Qemu-devel] [PATCH COLO-Frame v12 09/38] COLO/migration: Create a new communication path from destination to source

[zhanghailiang]

This new communication path will be used for returning messages
from destination to source.

Signed-off-by: zhanghailiang <address@hidden>
Signed-off-by: Li Zhijian <address@hidden>
Reviewed-by: Dr. David Alan Gilbert <address@hidden>
---
v12:
- Add Reviewed-by tag
v11:
- Rebase master to use qemu_file_get_return_path() for opening return path
v10:
- fix the the error log (Dave's suggestion).

Signed-off-by: zhanghailiang <address@hidden>
---
 migration/colo.c | 39 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/migration/colo.c b/migration/colo.c
index 6880aa0..0ab9618 100644
--- a/migration/colo.c
+++ b/migration/colo.c
@@ -36,6 +36,15 @@ bool migration_incoming_in_colo_state(void)
 
 static void colo_process_checkpoint(MigrationState *s)
 {
+    int ret = 0;
+
+    s->rp_state.from_dst_file = qemu_file_get_return_path(s->to_dst_file);
+    if (!s->rp_state.from_dst_file) {
+        ret = -EINVAL;
+        error_report("Open QEMUFile from_dst_file failed");
+        goto out;
+    }
+
     qemu_mutex_lock_iothread();
     vm_start();
     qemu_mutex_unlock_iothread();
@@ -43,8 +52,16 @@ static void colo_process_checkpoint(MigrationState *s)
 
     /*TODO: COLO checkpoint savevm loop*/
 
+out:
+    if (ret < 0) {
+        error_report("%s: %s", __func__, strerror(-ret));
+    }
     migrate_set_state(&s->state, MIGRATION_STATUS_COLO,
                       MIGRATION_STATUS_COMPLETED);
+
+    if (s->rp_state.from_dst_file) {
+        qemu_fclose(s->rp_state.from_dst_file);
+    }
 }
 
 void migrate_start_colo_process(MigrationState *s)
@@ -59,12 +76,34 @@ void migrate_start_colo_process(MigrationState *s)
 void *colo_process_incoming_thread(void *opaque)
 {
     MigrationIncomingState *mis = opaque;
+    int ret = 0;
 
     migrate_set_state(&mis->state, MIGRATION_STATUS_ACTIVE,
                       MIGRATION_STATUS_COLO);
 
+    mis->to_src_file = qemu_file_get_return_path(mis->from_src_file);
+    if (!mis->to_src_file) {
+        ret = -EINVAL;
+        error_report("colo incoming thread: Open QEMUFile to_src_file failed");
+        goto out;
+    }
+    /* Note: We set the fd to unblocked in migration incoming coroutine,
+    *  But here we are in the colo incoming thread, so it is ok to set the
+    *  fd back to blocked.
+    */
+    qemu_set_block(qemu_get_fd(mis->from_src_file));
+
     /* TODO: COLO checkpoint restore loop */
 
+out:
+    if (ret < 0) {
+        error_report("colo incoming thread will exit, detect error: %s",
+                     strerror(-ret));
+    }
+
+    if (mis->to_src_file) {
+        qemu_fclose(mis->to_src_file);
+    }
     migration_incoming_exit_colo();
 
     return NULL;
-- 
1.8.3.1