[PATCH v4 5/5] qemu: Wait for migration events on domain condition

[Jiri Denemark <jdenemar@xxxxxxxxxx>]

Since we already support the MIGRATION event, we just need to make sure
the domain condition is signalled whenever a p2p connection drops or the
domain is paused due to IO error and we can avoid waking up every 50 ms
to check whether something happened.

Signed-off-by: Jiri Denemark <jdenemar@xxxxxxxxxx>
---

Notes:
    ACKed in version 2
    
    Version 4:
    - no change
    
    Version 3:
    - no change
    
    Version 2:
    - new patch

 src/qemu/qemu_domain.h    |  3 +++
 src/qemu/qemu_migration.c | 45 +++++++++++++++++++++++++++++++++++++++------
 src/qemu/qemu_process.c   |  3 +++
 3 files changed, 45 insertions(+), 6 deletions(-)

diff --git a/src/qemu/qemu_domain.h b/src/qemu/qemu_domain.h
index 66dbcf5..2af7c59 100644
--- a/src/qemu/qemu_domain.h
+++ b/src/qemu/qemu_domain.h
@@ -199,6 +199,9 @@ struct _qemuDomainObjPrivate {
     /* Bitmaps below hold data from the auto NUMA feature */
     virBitmapPtr autoNodeset;
     virBitmapPtr autoCpuset;
+
+    bool signalIOError; /* true if the domain condition should be signalled on
+                           I/O error */
 };
 
 # define QEMU_DOMAIN_DISK_PRIVATE(disk)	\
diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c
index 9a50923..fa8c7d2 100644
--- a/src/qemu/qemu_migration.c
+++ b/src/qemu/qemu_migration.c
@@ -2661,20 +2661,28 @@ qemuMigrationWaitForCompletion(virQEMUDriverPtr driver,
 {
     qemuDomainObjPrivatePtr priv = vm->privateData;
     qemuDomainJobInfoPtr jobInfo = priv->job.current;
+    bool events = virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_MIGRATION_EVENT);
     int rv;
 
     jobInfo->type = VIR_DOMAIN_JOB_UNBOUNDED;
     while ((rv = qemuMigrationCompleted(driver, vm, asyncJob, dconn,
                                         abort_on_error, storage)) != 1) {
-        /* Poll every 50ms for progress & to allow cancellation */
-        struct timespec ts = { .tv_sec = 0, .tv_nsec = 50 * 1000 * 1000ull };
-
         if (rv < 0)
             return rv;
 
-        virObjectUnlock(vm);
-        nanosleep(&ts, NULL);
-        virObjectLock(vm);
+        if (events) {
+            if (virDomainObjWait(vm) < 0) {
+                jobInfo->type = VIR_DOMAIN_JOB_FAILED;
+                return -2;
+            }
+        } else {
+            /* Poll every 50ms for progress & to allow cancellation */
+            struct timespec ts = { .tv_sec = 0, .tv_nsec = 50 * 1000 * 1000ull };
+
+            virObjectUnlock(vm);
+            nanosleep(&ts, NULL);
+            virObjectLock(vm);
+        }
     }
 
     qemuDomainJobInfoUpdateDowntime(jobInfo);
@@ -4148,6 +4156,7 @@ qemuMigrationRun(virQEMUDriverPtr driver,
     virErrorPtr orig_err = NULL;
     unsigned int cookieFlags = 0;
     bool abort_on_error = !!(flags & VIR_MIGRATE_ABORT_ON_ERROR);
+    bool events = virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_MIGRATION_EVENT);
     int rc;
 
     VIR_DEBUG("driver=%p, vm=%p, cookiein=%s, cookieinlen=%d, "
@@ -4178,6 +4187,9 @@ qemuMigrationRun(virQEMUDriverPtr driver,
         return -1;
     }
 
+    if (events)
+        priv->signalIOError = abort_on_error;
+
     mig = qemuMigrationEatCookie(driver, vm, cookiein, cookieinlen,
                                  cookieFlags | QEMU_MIGRATION_COOKIE_GRAPHICS);
     if (!mig)
@@ -4387,6 +4399,9 @@ qemuMigrationRun(virQEMUDriverPtr driver,
 
     qemuMigrationCookieFree(mig);
 
+    if (events)
+        priv->signalIOError = false;
+
     if (orig_err) {
         virSetError(orig_err);
         virFreeError(orig_err);
@@ -5029,6 +5044,18 @@ doPeer2PeerMigrate3(virQEMUDriverPtr driver,
 }
 
 
+static void
+qemuMigrationConnectionClosed(virConnectPtr conn,
+                              int reason,
+                              void *opaque)
+{
+    virDomainObjPtr vm = opaque;
+
+    VIR_DEBUG("conn=%p, reason=%d, vm=%s", conn, reason, vm->def->name);
+    virDomainObjSignal(vm);
+}
+
+
 static int virConnectCredType[] = {
     VIR_CRED_AUTHNAME,
     VIR_CRED_PASSPHRASE,
@@ -5104,6 +5131,11 @@ static int doPeer2PeerMigrate(virQEMUDriverPtr driver,
                                cfg->keepAliveCount) < 0)
         goto cleanup;
 
+    if (virConnectRegisterCloseCallback(dconn, qemuMigrationConnectionClosed,
+                                        vm, NULL) < 0) {
+        goto cleanup;
+    }
+
     qemuDomainObjEnterRemote(vm);
     p2p = VIR_DRV_SUPPORTS_FEATURE(dconn->driver, dconn,
                                    VIR_DRV_FEATURE_MIGRATION_P2P);
@@ -5169,6 +5201,7 @@ static int doPeer2PeerMigrate(virQEMUDriverPtr driver,
  cleanup:
     orig_err = virSaveLastError();
     qemuDomainObjEnterRemote(vm);
+    virConnectUnregisterCloseCallback(dconn, qemuMigrationConnectionClosed);
     virObjectUnref(dconn);
     qemuDomainObjExitRemote(vm);
     if (orig_err) {
diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index 2cd6a52..db44a44 100644
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -952,6 +952,9 @@ qemuProcessHandleIOError(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
         qemuDomainObjPrivatePtr priv = vm->privateData;
         VIR_DEBUG("Transitioned guest %s to paused state due to IO error", vm->def->name);
 
+        if (priv->signalIOError)
+            virDomainObjSignal(vm);
+
         virDomainObjSetState(vm, VIR_DOMAIN_PAUSED, VIR_DOMAIN_PAUSED_IOERROR);
         lifecycleEvent = virDomainEventLifecycleNewFromObj(vm,
                                                   VIR_DOMAIN_EVENT_SUSPENDED,
-- 
2.4.5

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