[libvirt] [PATCH] qemu: process: Refresh data from qemu monitor after migration

[Peter Krempa]

Some values we read from the qemu monitor may be changed with the actual
state by the incomming migration. This means that we should refresh
certain things only after the migration has finished.

This is mostly visible in the cdrom tray state, which is by default
closed but may be opened by the guest OS. This would be refreshed before
qemu transferred the actual state and thus libvirt would think that the
tray is closed.

Note that this patch moves only a few obvious query commands. Other may
be moved later after individual assesment.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1463168
---
 src/qemu/qemu_process.c | 59 +++++++++++++++++++++++++++++++++++--------------
 1 file changed, 43 insertions(+), 16 deletions(-)

diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index c104985aa..2be82e958 100644
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -5787,14 +5787,6 @@ qemuProcessLaunch(virConnectPtr conn,
     if (qemuProcessSetLinkStates(driver, vm, asyncJob) < 0)
         goto cleanup;

-    VIR_DEBUG("Fetching list of active devices");
-    if (qemuDomainUpdateDeviceList(driver, vm, asyncJob) < 0)
-        goto cleanup;
-
-    VIR_DEBUG("Updating info of memory devices");
-    if (qemuDomainUpdateMemoryDeviceInfo(driver, vm, asyncJob) < 0)
-        goto cleanup;
-
     VIR_DEBUG("Setting initial memory amount");
     if (qemuProcessSetupBalloon(driver, vm, asyncJob) < 0)
         goto cleanup;
@@ -5806,14 +5798,6 @@ qemuProcessLaunch(virConnectPtr conn,
         qemuProcessRefreshBalloonState(driver, vm, asyncJob) < 0)
         goto cleanup;

-    VIR_DEBUG("Detecting actual memory size for video device");
-    if (qemuProcessUpdateVideoRamSize(driver, vm, asyncJob) < 0)
-        goto cleanup;
-
-    VIR_DEBUG("Updating disk data");
-    if (qemuProcessRefreshDisks(driver, vm, asyncJob) < 0)
-        goto cleanup;
-
     if (flags & VIR_QEMU_PROCESS_START_AUTODESTROY &&
         qemuProcessAutoDestroyAdd(driver, vm, conn) < 0)
         goto cleanup;
@@ -5831,6 +5815,46 @@ qemuProcessLaunch(virConnectPtr conn,
 }


+/**
+ * qemuProcessRefreshState:
+ * @driver: qemu driver data
+ * @vm: domain to refresh
+ * @asyncJob: async job type
+ *
+ * This function gathers calls to refresh qemu state after startup. This
+ * function is called after a deferred migration finishes so that we can update
+ * state influenced by the migration stream.
+ */
+static int
+qemuProcessRefreshState(virQEMUDriverPtr driver,
+                        virDomainObjPtr vm,
+                        qemuDomainAsyncJob asyncJob)
+{
+    int ret = -1;
+
+    VIR_DEBUG("Fetching list of active devices");
+    if (qemuDomainUpdateDeviceList(driver, vm, asyncJob) < 0)
+        goto cleanup;
+
+    VIR_DEBUG("Updating info of memory devices");
+    if (qemuDomainUpdateMemoryDeviceInfo(driver, vm, asyncJob) < 0)
+        goto cleanup;
+
+    VIR_DEBUG("Detecting actual memory size for video device");
+    if (qemuProcessUpdateVideoRamSize(driver, vm, asyncJob) < 0)
+        goto cleanup;
+
+    VIR_DEBUG("Updating disk data");
+    if (qemuProcessRefreshDisks(driver, vm, asyncJob) < 0)
+        goto cleanup;
+
+    ret = 0;
+
+ cleanup:
+    return ret;
+}
+
+
 /**
  * qemuProcessFinishStartup:
  *
@@ -5847,6 +5871,9 @@ 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,
-- 
2.14.1