qemu: Use -incoming defer for migrations

Traditionally, we pass incoming migration URI on QEMU command line,
which has some drawbacks. Depending on the URI QEMU may initialize its
migration state immediately without giving us a chance to set any
additional migration parameters (this applies mainly for fd: URIs). For
some URIs the monitor may be completely blocked from the beginning until
migration is finished, which means we may be stuck in qmp_capabilities
command without being able to send any QMP commands.

QEMU solved this by introducing "defer" parameter for -incoming command
line option. This will tell QEMU to prepare for an incoming migration
while the actual incoming URI is sent using migrate-incoming QMP
command. Before calling this command we can normally talk to the
monitor and even set any migration parameters which will be honored by
the incoming migration.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>

diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c
index 7475298357c15ce262d1207dc931d37d0c43663e..2813212c755be3d2e3e4b882c5e699970ed802f2 100644 (file)
--- a/src/qemu/qemu_capabilities.c
+++ b/src/qemu/qemu_capabilities.c
@@ -299,6 +299,8 @@ VIR_ENUM_IMPL(virQEMUCaps, QEMU_CAPS_LAST,
               "e1000",
               "virtio-net",
               "gic-version",
+
+              "incoming-defer", /* 200 */
     );
 
 
@@ -1458,6 +1460,7 @@ struct virQEMUCapsStringFlags virQEMUCapsCommands[] = {
     { "nbd-server-start", QEMU_CAPS_NBD_SERVER },
     { "change-backing-file", QEMU_CAPS_CHANGE_BACKING_FILE },
     { "rtc-reset-reinjection", QEMU_CAPS_RTC_RESET_REINJECTION },
+    { "migrate-incoming", QEMU_CAPS_INCOMING_DEFER },
 };
 
 struct virQEMUCapsStringFlags virQEMUCapsMigration[] = {

diff --git a/src/qemu/qemu_capabilities.h b/src/qemu/qemu_capabilities.h
index 14541f629eb0fb756c396b65bd46814196e3d6fe..e3e40e59543df0d2c49f1faa41b41fcc619bdd0f 100644 (file)
--- a/src/qemu/qemu_capabilities.h
+++ b/src/qemu/qemu_capabilities.h
@@ -325,6 +325,9 @@ typedef enum {
     QEMU_CAPS_DEVICE_VIRTIO_NET, /* -device virtio-net-* */
     QEMU_CAPS_MACH_VIRT_GIC_VERSION, /* -machine virt,gic-version */
 
+    /* 200 */
+    QEMU_CAPS_INCOMING_DEFER, /* -incoming defer and migrate_incoming */
+
     QEMU_CAPS_LAST /* this must always be the last item */
 } virQEMUCapsFlags;
 

diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c
index 4d5b966b2537a4871bbdbef5d9db0d00b60479a4..0c4c94aeea4271e9976269f758b87f6536cf3484 100644 (file)
--- a/src/qemu/qemu_migration.c
+++ b/src/qemu/qemu_migration.c
@@ -2951,6 +2951,42 @@ qemuMigrationIncomingURI(const char *migrateFrom,
 }
 
 
+int
+qemuMigrationRunIncoming(virQEMUDriverPtr driver,
+                         virDomainObjPtr vm,
+                         const char *uri,
+                         qemuDomainAsyncJob asyncJob)
+{
+    qemuDomainObjPrivatePtr priv = vm->privateData;
+    int ret = -1;
+    int rv;
+
+    VIR_DEBUG("Setting up incoming migration with URI %s", uri);
+
+    if (qemuDomainObjEnterMonitorAsync(driver, vm, asyncJob) < 0)
+        return -1;
+
+    rv = qemuMonitorMigrateIncoming(priv->mon, uri);
+
+    if (qemuDomainObjExitMonitor(driver, vm) < 0 || rv < 0)
+        goto cleanup;
+
+    if (asyncJob == QEMU_ASYNC_JOB_MIGRATION_IN) {
+        /* qemuMigrationWaitForDestCompletion is called from the Finish phase */
+        ret = 0;
+        goto cleanup;
+    }
+
+    if (qemuMigrationWaitForDestCompletion(driver, vm, asyncJob) < 0)
+        goto cleanup;
+
+    ret = 0;
+
+ cleanup:
+    return ret;
+}
+
+
 /* This is called for outgoing non-p2p migrations when a connection to the
  * client which initiated the migration was closed but we were waiting for it
  * to follow up with the next phase, that is, in between

diff --git a/src/qemu/qemu_migration.h b/src/qemu/qemu_migration.h
index ff4fe30b88f580e66d029a71db749543c3923b06..2445e13936333d3865017ff8bee786471d61142e 100644 (file)
--- a/src/qemu/qemu_migration.h
+++ b/src/qemu/qemu_migration.h
@@ -205,4 +205,9 @@ int qemuMigrationCheckIncoming(virQEMUCapsPtr qemuCaps,
 char *qemuMigrationIncomingURI(const char *migrateFrom,
                                int migrateFd);
 
+int qemuMigrationRunIncoming(virQEMUDriverPtr driver,
+                             virDomainObjPtr vm,
+                             const char *uri,
+                             qemuDomainAsyncJob asyncJob);
+
 #endif /* __QEMU_MIGRATION_H__ */

diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index 1b20f412f58d7360ffbb89169c4a0f84608c3901..82f914ac39ade65aa88a4968c7aba38880779892 100644 (file)
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -4168,6 +4168,7 @@ qemuProcessIncomingDefFree(qemuProcessIncomingDefPtr inc)
         return;
 
     VIR_FREE(inc->launchURI);
+    VIR_FREE(inc->deferredURI);
     VIR_FREE(inc);
 }
 
@@ -4195,6 +4196,12 @@ qemuProcessIncomingDefNew(virQEMUCapsPtr qemuCaps,
     if (!inc->launchURI)
         goto error;
 
+    if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_INCOMING_DEFER)) {
+        inc->deferredURI = inc->launchURI;
+        if (VIR_STRDUP(inc->launchURI, "defer") < 0)
+            goto error;
+    }
+
     inc->fd = fd;
     inc->path = path;
 
@@ -4940,6 +4947,11 @@ int qemuProcessStart(virConnectPtr conn,
     if (qemuProcessUpdateVideoRamSize(driver, vm, asyncJob) < 0)
         goto error;
 
+    if (incoming &&
+        incoming->deferredURI &&
+        qemuMigrationRunIncoming(driver, vm, incoming->deferredURI, asyncJob) < 0)
+        goto error;
+
     if (!(flags & VIR_QEMU_PROCESS_START_PAUSED)) {
         VIR_DEBUG("Starting domain CPUs");
         /* Allow the CPUS to start executing */

diff --git a/src/qemu/qemu_process.h b/src/qemu/qemu_process.h
index dcba72816210f6c64a0d89717a1970c905c30ea4..dcb7e2848e672e355db64c9a473d89744c819481 100644 (file)
--- a/src/qemu/qemu_process.h
+++ b/src/qemu/qemu_process.h
@@ -48,6 +48,7 @@ typedef struct _qemuProcessIncomingDef qemuProcessIncomingDef;
 typedef qemuProcessIncomingDef *qemuProcessIncomingDefPtr;
 struct _qemuProcessIncomingDef {
     char *launchURI; /* used as a parameter for -incoming command line option */
+    char *deferredURI; /* used when calling migrate-incoming QMP command */
     int fd; /* for fd:N URI */
     const char *path; /* path associated with fd */
 };

diff --git a/tests/qemucapabilitiesdata/caps_2.4.0-1.caps b/tests/qemucapabilitiesdata/caps_2.4.0-1.caps
index 0d1b1c0818ae3e9dcbab53cfae88e994895fca18..6694b7dbc1c1ee7c530617ddfd325880cb30b766 100644 (file)
--- a/tests/qemucapabilitiesdata/caps_2.4.0-1.caps
+++ b/tests/qemucapabilitiesdata/caps_2.4.0-1.caps
@@ -161,4 +161,5 @@
     <flag name='rtl8139'/>
     <flag name='e1000'/>
     <flag name='virtio-net'/>
+    <flag name='incoming-defer'/>
   </qemuCaps>