[libvirt] [PATCH v2 3/5] qemu: Pass running reason to RESUME event handler

[Jiri Denemark]

Whenever we get the RESUME event from QEMU, we change the state of the
affected domain to VIR_DOMAIN_RUNNING with VIR_DOMAIN_RUNNING_UNPAUSED
reason. This is fine if the domain is resumed unexpectedly, but when we
sent "cont" to QEMU we usually have a better reason for the state
change. The better reason is used in qemuProcessStartCPUs which also
sets the domain state to running if qemuMonitorStartCPUs reports
success. Thus we may end up with two state updates in a row, but the
final reason is correct.

This patch is a preparation for dropping the state change done in
qemuMonitorStartCPUs for which we need to pass the actual running reason
to the RESUME event handler and use it there instead of
VIR_DOMAIN_RUNNING_UNPAUSED.

Signed-off-by: Jiri Denemark <jdenemar at redhat.com>
Reviewed-by: John Ferlan <jferlan at redhat.com>
---

Notes:
    Version 2:
    - no change

 src/qemu/qemu_domain.h  |  4 ++++
 src/qemu/qemu_process.c | 23 +++++++++++++++++------
 2 files changed, 21 insertions(+), 6 deletions(-)

diff --git a/src/qemu/qemu_domain.h b/src/qemu/qemu_domain.h
index ecbe2e8533..461859e37f 100644
--- a/src/qemu/qemu_domain.h
+++ b/src/qemu/qemu_domain.h
@@ -366,6 +366,10 @@ struct _qemuDomainObjPrivate {
 
     /* counter for generating node names for qemu disks */
     unsigned long long nodenameindex;
+
+    /* qemuProcessStartCPUs stores the reason for starting vCPUs here for the
+     * RESUME event handler to use it */
+    virDomainRunningReason runningReason;
 };
 
 # define QEMU_DOMAIN_PRIVATE(vm) \
diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index 417e47ec29..f79db1d4cf 100644
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -712,21 +712,28 @@ qemuProcessHandleResume(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
     virQEMUDriverPtr driver = opaque;
     virObjectEventPtr event = NULL;
     virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);
+    qemuDomainObjPrivatePtr priv;
+    virDomainRunningReason reason = VIR_DOMAIN_RUNNING_UNPAUSED;
 
     virObjectLock(vm);
-    if (virDomainObjGetState(vm, NULL) == VIR_DOMAIN_PAUSED) {
-        qemuDomainObjPrivatePtr priv = vm->privateData;
 
+    priv = vm->privateData;
+    if (priv->runningReason != VIR_DOMAIN_RUNNING_UNKNOWN) {
+        reason = priv->runningReason;
+        priv->runningReason = VIR_DOMAIN_RUNNING_UNKNOWN;
+    }
+
+    if (virDomainObjGetState(vm, NULL) == VIR_DOMAIN_PAUSED) {
         if (priv->gotShutdown) {
             VIR_DEBUG("Ignoring RESUME event after SHUTDOWN");
             goto unlock;
         }
 
-        VIR_DEBUG("Transitioned guest %s out of paused into resumed state",
-                  vm->def->name);
+        VIR_DEBUG("Transitioned guest %s out of paused into resumed state, "
+                  "reason '%s'",
+                  vm->def->name, virDomainRunningReasonTypeToString(reason));
 
-        virDomainObjSetState(vm, VIR_DOMAIN_RUNNING,
-                                 VIR_DOMAIN_RUNNING_UNPAUSED);
+        virDomainObjSetState(vm, VIR_DOMAIN_RUNNING, reason);
         event = virDomainEventLifecycleNewFromObj(vm,
                                          VIR_DOMAIN_EVENT_RESUMED,
                                          VIR_DOMAIN_EVENT_RESUMED_UNPAUSED);
@@ -3087,6 +3094,8 @@ qemuProcessStartCPUs(virQEMUDriverPtr driver, virDomainObjPtr vm,
     }
     VIR_FREE(priv->lockState);
 
+    priv->runningReason = reason;
+
     if (qemuDomainObjEnterMonitorAsync(driver, vm, asyncJob) < 0)
         goto release;
 
@@ -3104,6 +3113,7 @@ qemuProcessStartCPUs(virQEMUDriverPtr driver, virDomainObjPtr vm,
     return ret;
 
  release:
+    priv->runningReason = VIR_DOMAIN_RUNNING_UNKNOWN;
     if (virDomainLockProcessPause(driver->lockManager, vm, &priv->lockState) < 0)
         VIR_WARN("Unable to release lease on %s", vm->def->name);
     VIR_DEBUG("Preserving lock state '%s'", NULLSTR(priv->lockState));
@@ -5987,6 +5997,7 @@ qemuProcessPrepareDomain(virQEMUDriverPtr driver,
     priv->monError = false;
     priv->monStart = 0;
     priv->gotShutdown = false;
+    priv->runningReason = VIR_DOMAIN_RUNNING_UNKNOWN;
 
     VIR_DEBUG("Updating guest CPU definition");
     if (qemuProcessUpdateGuestCPU(vm->def, priv->qemuCaps, caps, flags) < 0)
-- 
2.19.0