qemu: migration: Refresh device information after transferring state

In my first approach in 4b480d10768c I overlooked the comment in
qemuMigrationRunIncoming stating that during actual migration the
qemuMigrationRunIncoming does not wait until the migration is complete
but rather offloads that to the Finish phase of migration.

This means that during actual migration qemuProcessRefreshState was
called prior to qemu actually transferring the full state and thus the
queries did not get the correct information. The approach worked only
for restore, where we wait for the migration to finish during qemu
startup.

Fix the issue by calling qemuProcessRefreshState both from
qemuProcessStart if there's no incomming migration and from
qemuMigrationFinish so that the code actually works as expected.

diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c
index 1854900c9a088fcae20e5533c0dc71853b886cd6..ea8b275601516960695cc0ae5c0cdcad832a98d6 100644 (file)
--- a/src/qemu/qemu_migration.c
+++ b/src/qemu/qemu_migration.c
@@ -5373,6 +5373,15 @@ qemuMigrationFinish(virQEMUDriverPtr driver,
             goto endjob;
     }
 
+    /* Now that the state data was transferred we can refresh the actual state
+     * of the devices */
+    if (qemuProcessRefreshState(driver, vm, QEMU_ASYNC_JOB_MIGRATION_IN) < 0) {
+        /* Similarly to the case above v2 protocol will not be able to recover
+         * from this. Let's ignore this and perhaps stuff will not break. */
+        if (v3proto)
+            goto endjob;
+    }
+
     if (priv->job.current->status == QEMU_DOMAIN_JOB_STATUS_POSTCOPY)
         inPostCopy = true;
 

diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index bcd4ac8ad699f141b95e091d3063822eadd64863..fe12d94d37802e14b8a4007f4e0c7543651679ff 100644 (file)
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -6084,7 +6084,7 @@ qemuProcessLaunch(virConnectPtr conn,
  * function is called after a deferred migration finishes so that we can update
  * state influenced by the migration stream.
  */
-static int
+int
 qemuProcessRefreshState(virQEMUDriverPtr driver,
                         virDomainObjPtr vm,
                         qemuDomainAsyncJob asyncJob)
@@ -6125,9 +6125,6 @@ qemuProcessFinishStartup(virConnectPtr conn,
     virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);
     int ret = -1;
 
-    if (qemuProcessRefreshState(driver, vm, asyncJob) < 0)
-        goto cleanup;
-
     if (startCPUs) {
         VIR_DEBUG("Starting domain CPUs");
         if (qemuProcessStartCPUs(driver, vm, conn,
@@ -6231,11 +6228,17 @@ qemuProcessStart(virConnectPtr conn,
                                  VIR_DOMAIN_PAUSED_USER) < 0)
         goto stop;
 
-    /* Keep watching qemu log for errors during incoming migration, otherwise
-     * unset reporting errors from qemu log. */
-    if (!incoming)
+    if (!incoming) {
+        /* Keep watching qemu log for errors during incoming migration, otherwise
+         * unset reporting errors from qemu log. */
         qemuMonitorSetDomainLog(priv->mon, NULL, NULL, NULL);
 
+        /* Refresh state of devices from qemu. During migration this needs to
+         * happen after the state information is fully transferred. */
+        if (qemuProcessRefreshState(driver, vm, asyncJob) < 0)
+            goto stop;
+    }
+
     ret = 0;
 
  cleanup:

diff --git a/src/qemu/qemu_process.h b/src/qemu/qemu_process.h
index cd9a7203139d0f77d2c93ac2b8fec52592a3d12e..b383ff309bf4d849a5ef5c57d4c5a51c3c62d31f 100644 (file)
--- a/src/qemu/qemu_process.h
+++ b/src/qemu/qemu_process.h
@@ -129,6 +129,10 @@ int qemuProcessFinishStartup(virConnectPtr conn,
                              bool startCPUs,
                              virDomainPausedReason pausedReason);
 
+int qemuProcessRefreshState(virQEMUDriverPtr driver,
+                            virDomainObjPtr vm,
+                            qemuDomainAsyncJob asyncJob);
+
 typedef enum {
     VIR_QEMU_PROCESS_STOP_MIGRATED      = 1 << 0,
     VIR_QEMU_PROCESS_STOP_NO_RELABEL    = 1 << 1,