Re: [libvirt] [PATCH 08/24] 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(a)redhat.com&gt; --- src/qemu/qemu_capabilities.c | 3 +++ src/qemu/qemu_capabilities.h | 3 +++ src/qemu/qemu_migration.c | 36 ++++++++++++++++++++++++++++ src/qemu/qemu_migration.h | 5 ++++ src/qemu/qemu_process.c | 12 ++++++++++ src/qemu/qemu_process.h | 1 + tests/qemucapabilitiesdata/caps_2.4.0-1.caps | 1 + 7 files changed, 61 insertions(+)

diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c index 4d5b966..0c4c94a 100644 --- 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; +} + + diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c index f85e876..3f236d4 100644 --- a/src/qemu/qemu_process.c +++ b/src/qemu/qemu_process.c

@@ -4929,6 +4936,11 @@ 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 */